Author: "Pierre Gratier" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Pierre Gratier"' showing total 176 results

Start Over Author "Pierre Gratier"

176 results on '"Pierre Gratier"'

1. A Decade with VAMDC: Results and Ambitions

Author: Damien Albert, Bobby K. Antony, Yaye Awa Ba, Yuri L. Babikov, Philippe Bollard, Vincent Boudon, Franck Delahaye, Giulio Del Zanna, Milan S. Dimitrijević, Brian J. Drouin, Marie-Lise Dubernet, Felix Duensing, Masahiko Emoto, Christian P. Endres, Alexandr Z. Fazliev, Jean-Michel Glorian, Iouli E. Gordon, Pierre Gratier, Christian Hill, Darko Jevremović, Christine Joblin, Duck-Hee Kwon, Roman V. Kochanov, Erumathadathil Krishnakumar, Giuseppe Leto, Petr A. Loboda, Anastasiya A. Lukashevskaya, Oleg M. Lyulin, Bratislav P. Marinković, Andrew Markwick, Thomas Marquart, Nigel J. Mason, Claudio Mendoza, Tom J. Millar, Nicolas Moreau, Serguei V. Morozov, Thomas Möller, Holger S. P. Müller, Giacomo Mulas, Izumi Murakami, Yury Pakhomov, Patrick Palmeri, Julien Penguen, Valery I. Perevalov, Nikolai Piskunov, Johannes Postler, Alexei I. Privezentsev, Pascal Quinet, Yuri Ralchenko, Yong-Joo Rhee, Cyril Richard, Guy Rixon, Laurence S. Rothman, Evelyne Roueff, Tatiana Ryabchikova, Sylvie Sahal-Bréchot, Paul Scheier, Peter Schilke, Stephan Schlemmer, Ken W. Smith, Bernard Schmitt, Igor Yu. Skobelev, Vladimir A. Srecković, Eric Stempels, Serguey A. Tashkun, Jonathan Tennyson, Vladimir G. Tyuterev, Charlotte Vastel, Veljko Vujčić, Valentine Wakelam, Nicholas A. Walton, Claude Zeippen, and Carlo Maria Zwölf
Subjects: scientific databases, atomic and molecular data, interoperability, FAIR principles, open access, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract: This paper presents an overview of the current status of the Virtual Atomic and Molecular Data Centre (VAMDC) e-infrastructure, including the current status of the VAMDC-connected (or to be connected) databases, updates on the latest technological development within the infrastructure and a presentation of some application tools that make use of the VAMDC e-infrastructure. We analyse the past 10 years of VAMDC development and operation, and assess their impact both on the field of atomic and molecular (A&M) physics itself and on heterogeneous data management in international cooperation. The highly sophisticated VAMDC infrastructure and the related databases developed over this long term make them a perfect resource of sustainable data for future applications in many fields of research. However, we also discuss the current limitations that prevent VAMDC from becoming the main publishing platform and the main source of A&M data for user communities, and present possible solutions under investigation by the consortium. Several user application examples are presented, illustrating the benefits of VAMDC in current research applications, which often need the A&M data from more than one database. Finally, we present our vision for the future of VAMDC.
Published: 2020
Full Text: View/download PDF

2. Mixture of noises and sampling of non-log-concave posterior distributions.

Author: Pierre Palud, Pierre Chainais, Franck Le Petit, Emeric Bron, Pierre-Antoine Thouvenin, Maxime Vono, L. Einig, M. Garcia Santa-Maria, Mathilde Gaudel, Jan H. Orkisz, Victor de Souza Magalhaes, Sébastien Bardeau, Maryvonne Gerin, Javier R. Goicoechea, Pierre Gratier, Viviana V. Guzmán, Jouni Kainulainen, François Levrier, Nicolas Peretto, Jérome Pety, Antoine Roueff, and Albrecht Sievers
Published: 2022

3. A Fully Bayesian Approach For Inferring Physical Properties With Credibility Intervals From Noisy Astronomical Data.

Author: Maxime Vono, Javier R. Goicoechea, Pierre Gratier, Viviana V. Guzmán, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, François Levrier, Harvey S. Listz, Karin I. Oberg, Emeric Bron, Jan H. Orkisz, Nicolas Peretto, Jérome Pety, Antoine Roueff, èvelyne Roueff, Albrecht Sievers, Victor de Souza Magalhaes, Pascal Tremblin, Pierre Chainais, Franck Le Petit, Sébastien Bardeau, Sébastien Bourguignon, Jocelyn Chanussot, Mathilde Gaudel, and Maryvonne Gerin
Published: 2019
Full Text: View/download PDF

4. Methyl cyanide (CH3CN) and propyne (CH3CCH) in the low-mass protostar IRAS 16293–2422

Author: Inès Andron, Pierre Gratier, Liton Majumdar, Thomas H G Vidal, Audrey Coutens, Jean-Christophe Loison, and Valentine Wakelam
Published: 2018
Full Text: View/download PDF

5. Slip localization by cataclasis and fluid-rock interaction in seismogenic crustal faults (Gole Larghe Fault, Italy)

Author: Silvia Mittempergher, Giulio Di Toro, Stefano Aretusini, Jean-Pierre Gratier, Andrea Bistacchi, and Tommaso Giovanardi
Abstract: At nucleation depths of earthquakes in the continental crust (7-15 km), cataclastic processes and fluids interact in a complex way, affecting the mechanical properties, deformation mechanisms and fabric of fault rocks. In this study, we analyzed the effects of cumulative displacement, fault orientation and slip localization on the fabric of low-displacement cataclasite-pseudotachylyte-bearing faults in granodiorite and discuss the feedbacks between deformation mechanisms potentially controlling the transition to unstable slip.The samples were stem from a well-exposed outcrop of the Gole Larghe Fault Zone (Southern Alps, Italy), which was active 30 Ma ago as a dextral transpressive fault at depths of earthquake nucleation (9-11 km, 250-280°C). Faults and shear fractures were digitized from an orthorectified photomosaic over an area of about 65 m2 to quantify their spatial arrangement. Samples were stem from faults and shear fractures which accommodated increasing cumulative displacements from 0 to 4.8 m, with strikes ranging from N074 to N125. Samples were characterized by means of microstructural (field emission scanning electron microscope, optical cathodoluminescence), mineralogical (X-Ray powder diffraction), geochemical (Energy Dispersive X-Ray Spectroscopy, EMPA) and image analysis (clast size distribution and shape parameters) investigations.Although fractures are uniformly distributed in the analyzed outcrop, 69% of the total displacement is accommodated along two main pseudotachylyte-bearing fault strands. Cataclasites consist of fragments of the wall rock (quartz, plagioclase and K-feldspar), in a matrix of K-feldspar, chlorite and epidote. With increasing displacement, the average grain size of quartz and plagioclase clasts decreases, the fractal dimension of the clast size distribution increases (from 1.6 to 2.8 in two dimensions) and the faults develop multiple domains of foliated cataclasites and non-foliated, highly comminuted ultracataclasites. If ultracataclasites or pseudotachylytes are present in the fault rocks, an increase of the displacement/thickness ratio suggests strain localization. The boundaries of quartz and plagioclase clasts in cataclasites are generally jagged, and clasts with equivalent diameters of less than 5 μm are rare, suggesting partial corrosion of the clast’s boundaries and dissolution of the smallest fragments. Elongated clasts are often oriented at an acute angle with fault boundaries, forming foliated cataclasite domains. Their iso-orientation is more intense in faults having a higher resolved normal stress (assuming a constant far-field stress tensor), i.e., the P-shears. Foliation is associated with an incipient mineral segregation of the matrix minerals, with epidote and titanite aligned along the foliation surfaces and K-feldspar and chlorite in low-strain sites.In agreement with experimental results, once slip localizes along highly comminuted horizons, slip appears to be further localized along it, suggesting slip weakening behavior associated with cataclastic flow. Diffusive mass transfer processes enhanced by comminution and fluid ingression allow a residual part of the displacement to be accommodated by frictional-viscous mechanisms (creep), especially at high driving stresses.
Published: 2023

6. Pressure Solution Grain Boundary Sliding as a Large Strain Mechanism of Superplastic Flow in the Upper Crust

Author: Jean‐Pierre Gratier, Luca Menegon, and François Renard
Subjects: Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous)
Published: 2023

7. Gas kinematics around filamentary structures in the Orion B cloud

Author: Mathilde Gaudel, Jan H. Orkisz, Maryvonne Gerin, Jérôme Pety, Antoine Roueff, Antoine Marchal, François Levrier, Marc-Antoine Miville-Deschênes, Javier R. Goicoechea, Evelyne Roueff, Franck Le Petit, Victor de Souza Magalhaes, Pierre Palud, Miriam G. Santa-Maria, Maxime Vono, Sébastien Bardeau, Emeric Bron, Pierre Chainais, Jocelyn Chanussot, Pierre Gratier, Viviana Guzman, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, Harvey Liszt, Karin Öberg, Nicolas Peretto, Albrecht Sievers, Pascal Tremblin, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), l'Observatoire de Paris, Ministerio de Ciencia, Innovación y Universidades (España), Swedish Research Council, Orkisz, Jan H., Pety, Jérôme, Roueff, Antoine, Marchal, Antoine, Levrier, François, Miville-Deschênes, Marc-Antoine, Goicoechea, Javier R., Roueff, Evelyne, Santa-Maria, Miriam G., Bron, Emeric, Chainais, Pierre, Chanussot, Jocelyn, Gratier, Pierre, Guzman, Viviana, Le Bourlot,Jacques, and Liszt, Harvey
Subjects: ISM: kinematics and dynamics, HII regions, ISM: individual objects: Orion B, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Stars: formation, FOS: Physical sciences, Astronomy and Astrophysics, ISM: clouds, Astrophysics - Astrophysics of Galaxies, Radio lines: ISM
Abstract: 39 pags., 78 figs., 2 tabs. 6 apps., Understanding the initial properties of star-forming material and how they affect the star formation process is key. From an observational point of view, the feedback from young high-mass stars on future star formation properties is still poorly constrained. In the framework of the IRAM 30m ORION-B large program, we obtained observations of the translucent and moderately dense gas, which we used to analyze the kinematics over a field of 5 deg^2 around the filamentary structures. We used the ROHSA algorithm to decompose and de-noise the C18O(1-0) and 13CO(1-0) signals by taking the spatial coherence of the emission into account. We produced gas column density and mean velocity maps to estimate the relative orientation of their spatial gradients. We identified three cloud velocity layers at different systemic velocities and extracted the filaments in each velocity layer. The filaments are preferentially located in regions of low centroid velocity gradients. By comparing the relative orientation between the column density and velocity gradients of each layer from the ORION-B observations and synthetic observations from 3D kinematic toy models, we distinguish two types of behavior in the dynamics around filaments: (i) radial flows perpendicular to the filament axis that can be either inflows (increasing the filament mass) or outflows and (ii) longitudinal flows along the filament axis. The former case is seen in the Orion B data, while the latter is not identified. We have also identified asymmetrical flow patterns, usually associated with filaments located at the edge of an HII region. This is the first observational study to highlight feedback from HII regions on filament formation and, thus, on star formation in the Orion B cloud. This simple statistical method can be used for any molecular cloud to obtain coherent information on the kinematics., This work was supported in part by the French Agence Nationale de la Recherche through the DAOISM grant ANR21-CE31-0010 and by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. We thank “le centre Jules Jensen” from Observatoire de Paris for its hospitality during the workshops devoted to this project. This research has made use of data from the Herschel Gould Belt Survey (HGBS) project (http: //gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). J.R.G. and M.G.S.M. thank the Spanish MCIYU for funding support under grant PID2019-106110GB-I00. J.O. acknowledges funding from the Swedish Research Council, grant No. 2017-03864.
Published: 2023

8. Chemical compositions of five Planck cold clumps

Author: R. Le Gal, Liton Majumdar, Kevin M. Hickson, M. Ruaud, Pierre Gratier, Valentine Wakelam, Jean-Christophe Loison, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2020, Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center (ARC), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], Institut des Sciences Moléculaires (ISM), and Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: clouds, ISM: abundances, chemistry.chemical_compound, Planet, 0103 physical sciences, Radiative transfer, Molecule, 010303 astronomy & astrophysics, Chemical composition, Physics, Cyanopolyyne, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, astrochemistry, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Stars, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], methods: observational, Order of magnitude
Abstract: Aims: Interstellar molecules form early in the evolutionary sequence of interstellar material that eventually forms stars and planets. To understand this evolutionary sequence, it is important to characterize the chemical composition of its first steps. Methods: In this paper, we present the result of a 2 and 3 mm survey of five cold clumps identified by the Planck mission. We carried out a radiative transfer analysis on the detected lines in order to put some constraints on the physical conditions within the cores and on the molecular column densities. We also performed chemical models to reproduce the observed abundances in each source using the gas-grain model Nautilus. Results: Twelve molecules were detected: H2CO, CS, SO, NO, HNO, HCO+, HCN, HNC, CN, CCH, CH3OH, and CO. Here, CCH is the only carbon chain we detected in two sources. Radiative transfer analyses of HCN, SO, CS, and CO were performed to constrain the physical conditions of each cloud with limited success. The sources have a density larger than $10^4$ cm$^{-3}$ and a temperature lower than 15 K. The derived species column densities are not very sensitive to the uncertainties in the physical conditions, within a factor of 2. The different sources seem to present significant chemical differences with species abundances spreading over one order of magnitude. The chemical composition of these clumps is poorer than the one of Taurus Molecular Cloud 1 Cyanopolyyne Peak (TMC-1 CP) cold core. Our chemical model reproduces the observational abundances and upper limits for 79 to 83\% of the species in our sources. The "best" times for our sources seem to be smaller than those of TMC-1, indicating that our sources may be less evolved and explaining the smaller abundances and the numerous non-detections. Also, CS and HCN are always overestimated by our models., Accepted for publication in A&A
Published: 2021

9. Tracers of the ionization fraction in dense and translucent gas: I. Automated exploitation of massive astrochemical model grids

Author: Emeric Bron, Antoine Roueff, Nicolas Peretto, Franck Le Petit, Albrecht Sievers, Viviana V. Guzmán, François Levrier, David Languignon, Victor de Souza Magalhaes, Javier R. Goicoechea, E. Roueff, Annie Hughes, Pierre Chainais, Mathilde Gaudel, Karin I. Öberg, Sébastien Bardeau, Maryvonne Gerin, Jacques Le Bourlot, Jouni Kainulainen, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Jérôme Pety, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Ministerio de Ciencia, Innovación y Universidades (España), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], School of Physics and Astronomy [Cardiff], Cardiff University, Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), PhyTI (PhyTI), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Programme National 'Physique et Chimie du Milieu Interstel-laire' (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES, MIT Iinterdisciplinary programs, Paris Observatory through the AFAstrochimie program, Spanish MICI - grant AYA2017-85111-P, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Harvard University-Smithsonian Institution, Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Harvard University [Cambridge]-Smithsonian Institution
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Flux, Fraction (chemistry), Context (language use), Astrophysics, ISM: clouds, 7. Clean energy, 01 natural sciences, Ionization, TRACER, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Methods: statistical, 0105 earth and related environmental sciences, Physics, Methods: numerical, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, ISM: lines and bands, Interstellar medium, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: 28 pags., 15 figs., 12 tabs., Context. The ionization fraction in the neutral interstellar medium (ISM) plays a key role in the physics and chemistry of the ISM, from controlling the coupling of the gas to the magnetic field to allowing fast ion-neutral reactions that drive interstellar chemistry. Most estimations of the ionization fraction have relied on deuterated species such as DCO+, whose detection is limited to dense cores representing an extremely small fraction of the volume of the giant molecular clouds that they are part of. As large field-of-view hyperspectral maps become available, new tracers may be found. The growth of observational datasets is paralleled by the growth of massive modeling datasets and new methods need to be devised to exploit the wealth of information they contain. Aims. We search for the best observable tracers of the ionization fraction based on a grid of astrochemical models, with the broader aim of finding a general automated method applicable to searching for tracers of any unobservable quantity based on grids of models. Methods. We built grids of models that randomly sample a large range of physical conditions (unobservable quantities such as gas density, temperature, elemental abundances, etc.) and computed the corresponding observables (line intensities, column densities) and the ionization fraction. We estimated the predictive power of each potential tracer by training a random forest model to predict the ionization fraction from that tracer, based on these model grids. Results. In both translucent medium and cold dense medium conditions, we found several observable tracers with very good predictive power for the ionization fraction. Many tracers in cold dense medium conditions are found to be better and more widely applicable than the traditional DCO+/HCO+ ratio. We also provide simpler analytical fits for estimating the ionization fraction from the best tracers, and for estimating the associated uncertainties. We discuss the limitations of the present study and select a few recommended tracers in both types of conditions. Conclusions. The method presented here is very general and can be applied to the measurement of any other quantity of interest (cosmic ray flux, elemental abundances, etc.) from any type of model (PDR models, time-dependent chemical models, etc.)., This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. The authors also acknowledge funding by Paris Observatory through the AF Astrochimie program. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.
Published: 2020

10. C18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud

Author: Emeric Bron, Marc-Antoine Miville-Deschenes, Pierre Gratier, Jérôme Pety, Jan H. Orkisz, Nicolas Peretto, Maxime Vono, Evelyne Roueff, Antoine Roueff, Albrecht Sievers, Javier R. Goicoechea, Jacques Le Bourlot, Victor de Souza Magalhaes, Jouni Kainulainen, Annie Hughes, Franck Petit, Viviana V. Guzmán, Maryvonne Gerin, Harvey S. Liszt, François Levrier, Antoine Marchal, Jocelyn Chanussot, David Languignon, Sébastien Bardeau, M. Gaudel, Pierre Chainais, Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), European Space Agency, Centre National D'Etudes Spatiales (France), Agencia Estatal de Investigación (España), PhyTI (PhyTI), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Canadian Institute for Theoretical Astrophysics (CITA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Cardiff University, ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Onsala Space Observatory, Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Ecole Centrale de Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: statistical [Methods], Astrophysics, 7. Clean energy, 01 natural sciences, Molecular physics, ISM: clouds, Spectral line, Methods: data analysis, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Isotopologue, [INFO]Computer Science [cs], data analysis [Methods], 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, Methods: statistical, Line (formation), Physics, 010308 nuclear & particles physics, Molecular cloud, Estimator, Velocity dispersion, Astronomy and Astrophysics, ISM: molecules, 3. Good health, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM], Excitation
Abstract: 27 pags., 23 figs., 3 tabs., Context. CO isotopologue transitions are routinely observed in molecular clouds for the purpose of probing the column density of the gas and the elemental ratios of carbon and oxygen, in addition to tracing the kinematics of the environment. Aims. Our study is aimed at estimating the abundances, excitation temperatures, velocity field, and velocity dispersions of the three main CO isotopologues towards a subset of the Orion B molecular cloud, which includes IC 434, NGC 2023, and the Horsehead pillar. Methods. We used the Cramer Rao bound (CRB) technique to analyze and estimate the precision of the physical parameters in the framework of local-thermodynamic-equilibrium (LTE) excitation and radiative transfer with added white Gaussian noise. We propose a maximum likelihood estimator to infer the physical conditions from the 1-0 and 2-1 transitions of CO isotopologues. Simulations show that this estimator is unbiased and proves efficient for a common range of excitation temperatures and column densities (Tex > 6 K, N > 1014-1015 cm-2). Results. Contrary to general assumptions, the various CO isotopologues have distinct excitation temperatures and the line intensity ratios between different isotopologues do not accurately reflect the column density ratios. We find mean fractional abundances that are consistent with previous determinations towards other molecular clouds. However, significant local deviations are inferred, not only in regions exposed to the UV radiation field, but also in shielded regions. These deviations result from the competition between selective photodissociation, chemical fractionation, and depletion on grain surfaces. We observe that the velocity dispersion of the C18O emission is 10% smaller than that of 13CO. The substantial gain resulting from the simultaneous analysis of two different rotational transitions of the same species is rigorously quantified. Conclusions. The CRB technique is a promising avenue for analyzing the estimation of physical parameters from the fit of spectral lines. Future works will generalize its application to non-LTE excitation and radiative transfer methods., This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This project has received financial support from the CNRS through the MITI interdisciplinary programs. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. JRG thanks Spanish MICI for funding support under grant AYA2017- 85111-P. Finally, we thank the anonymous referee for helpful comments on the manuscript.
Published: 2020

11. A Decade with VAMDC: Results and Ambitions

Author: Carlo Maria Zwölf, A. J. Markwick, Anastasiya A. Lukashevskaya, Tom J. Millar, Patrick Palmeri, M. Emoto, Yuri Ralchenko, Thomas Marquart, Felix Duensing, Evelyne Roueff, Duck-Hee Kwon, Pascal Quinet, Johannes Postler, Julien Penguen, Izumi Murakami, Vincent Boudon, Bobby Antony, Paul Scheier, Milan S. Dimitrijević, Christine Joblin, Valery I. Perevalov, Vladimir G. Tyuterev, Jean-Michel Glorian, Tatiana Ryabchikova, Valentine Wakelam, E. Krishnakumar, Igor Y.-U. Skobelev, Philippe Bollard, Guy Rixon, Laurence S. Rothman, Sylvie Sahal-Bréchot, Giacomo Mulas, Damien Albert, Nicolas Moreau, Bernard Schmitt, Alexandr Z. Fazliev, Peter Schilke, Giulio Del Zanna, Stephan Schlemmer, Eric Stempels, Nicholas A. Walton, Bratislav P. Marinković, Serguey A. Tashkun, Charlotte Vastel, Yury Pakhomov, Claudio Mendoza, K. W. Smith, Thomas Möller, Oleg M. Lyulin, Brian J. Drouin, Roman V. Kochanov, Alexei I. Privezentsev, Vladimir A. Srećković, Darko Jevremović, Giuseppe Leto, Iouli E. Gordon, Serguei V. Morozov, Nigel J. Mason, C. J. Zeippen, Yong-Joo Rhee, Petr A. Loboda, Veljko Vujčić, Pierre Gratier, Jonathan Tennyson, Marie-Lise Dubernet, Cyril Richard, Franck Delahaye, Christian Hill, Yuri L. Babikov, Christian P. Endres, Holger S. P. Müller, Nikolai Piskunov, Yaye Awa Ba, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Department of Environmental, Earth, and Atmospheric Sciences [Lowell], University of Massachusetts [Lowell] (UMass Lowell), University of Massachusetts System (UMASS)-University of Massachusetts System (UMASS), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire Interdisciplinaire Carnot de Bourgogne [Dijon] (LICB), Université de Bourgogne (UB)-Université de Technologie de Belfort-Montbeliard (UTBM)-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, INAF - Osservatorio Astronomico di Cagliari (OAC), Istituto Nazionale di Astrofisica (INAF), Del Zanna, Giulio [0000-0002-4125-0204], Walton, Nicholas [0000-0003-3983-8778], Apollo - University of Cambridge Repository, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire Interdisciplinaire Carnot de Bourgogne (ICB), Université de Technologie de Belfort-Montbeliard (UTBM)-Université de Bourgogne (UB)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL)
Subjects: Nuclear and High Energy Physics, 010504 meteorology & atmospheric sciences, Data management, Atom and Molecular Physics and Optics, Interoperability, interoperability, 01 natural sciences, Field (computer science), Resource (project management), 0103 physical sciences, lcsh:Nuclear and particle physics. Atomic energy. Radioactivity, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, open access, [PHYS]Physics [physics], atomic and molecular data, scientific databases, FAIR principles, business.industry, Condensed Matter Physics, Data science, Atomic and Molecular Physics, and Optics, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, lcsh:QC770-798, Data center, Atom- och molekylfysik och optik, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This paper presents an overview of the current status of the Virtual Atomic and Molecular Data Centre (VAMDC) e-infrastructure, including the current status of the VAMDC-connected (or to be connected) databases, updates on the latest technological development within the infrastructure and a presentation of some application tools that make use of the VAMDC e-infrastructure. We analyse the past 10 years of VAMDC development and operation, and assess their impact both on the field of atomic and molecular (A&amp, M) physics itself and on heterogeneous data management in international cooperation. The highly sophisticated VAMDC infrastructure and the related databases developed over this long term make them a perfect resource of sustainable data for future applications in many fields of research. However, we also discuss the current limitations that prevent VAMDC from becoming the main publishing platform and the main source of A&amp, M data for user communities, and present possible solutions under investigation by the consortium. Several user application examples are presented, illustrating the benefits of VAMDC in current research applications, which often need the A&amp, M data from more than one database. Finally, we present our vision for the future of VAMDC.
Published: 2020

12. Gas-grain model of carbon fractionation in dense molecular clouds

Author: Jean-Christophe Loison, Pierre Gratier, Kevin M. Hickson, Valentine Wakelam, Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), AMOR 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, Astrochemistry, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Fractionation, 01 natural sciences, chemistry.chemical_compound, 0103 physical sciences, Molecule, Isotopologue, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Molecular cloud, Astronomy and Astrophysics, Hydrogen atom, Astrophysics - Astrophysics of Galaxies, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Atomic carbon, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Carbon containing molecules in cold molecular clouds show various levels of isotopic fractionation through multiple observations. To understand such effects, we have developed a new gas-grain chemical model with updated 13C fractionation reactions (also including the corresponding reactions for 15N, 18O and 34S). For chemical ages typical of dense clouds, our nominal model leads to two 13C reservoirs: CO and the species that derive from CO, mainly s-CO and s-CH3OH, as well as C3 in the gas phase. The nominal model leads to strong enrichment in C3, c-C3H2 and C2H in contradiction with observations. When C3 reacts with oxygen atoms the global agreement between the various observations and the simulations is rather good showing variable 13C fractionation levels which are specific to each species. Alternatively, hydrogen atom reactions lead to notable relative 13C fractionation effects for the two non-equivalent isotopologues of C2H, c-C3H2 and C2S. As there are several important fractionation reactions, some carbon bearing species are enriched in 13C, particularly CO, depleting atomic 13C in the gas phase. This induces a 13C depletion in CH4 formed on grain surfaces, an effect that is not observed in the CH4 in the solar system, in particular on Titan. This seems to indicate a transformation of matter between the collapse of the molecular clouds, leading to the formation of the protostellar disc, and the formation of the planets. Or it means that the atomic carbon sticking to the grains reacts with the species already on the grains giving very little CH4., Accepted in MNRAS. 33 pages, 15 figures
Published: 2020

13. Quantitative inference of the H2 column densities from 3 mm molecular emission: A case study towards Orion B

Author: Javier R. Goicoechea, M. Gaudel, Victor de Souza Magalhaes, François Levrier, David Languignon, Maryvonne Gerin, Franck Petit, Viviana V. Guzmán, Pierre Chainais, Annie Hughes, Albrecht Sievers, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Sébastien Bardeau, Nicolas Peretto, Jocelyn Chanussot, Jérôme Pety, Jacques Le Bourlot, Evelyne Roueff, Antoine Roueff, Jouni Kainulainen, Emeric Bron, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), PhyTI (PhyTI), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, CNRS through the MITI interdisciplinary programs, Spanish MICI under grant AYA2017-85111-P, ORION-B project, Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) - CNRS/INSU - INC/INP, co-funded by CEA and CNES, IRAM supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain), Data from the CEA Herschel Gould Belt survey (HGBS) project (http://gouldbelt-herschel.cea.fr), HGBS : Herschel Key Programme, SPIRE Specialist Astronomy Group 3 (SAG 3), PACS Consortium (CEA Saclay, INAF-IFSI Rome INAF-Arcetri,KU Leuven, MPIA Heidelberg), Herschel Science Center (HSC), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Chalmers University of Technology [Gothenburg, Sweden], Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Apprentissage de modèles à partir de données massives (Thoth), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), Université Paris-Saclay, Istituto Nazionale di Astrofisica, and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: statistical [Methods], Field (physics), Astro-ph.IM, FOS: Physical sciences, Context (language use), Astrophysics, 7. Clean energy, 01 natural sciences, Column (database), ISM: clouds, 0103 physical sciences, Angular resolution, [INFO]Computer Science [cs], 010303 astronomy & astrophysics, Stellar density, Instrumentation and Methods for Astrophysics (astro-ph.IM), molecules [ISM], Astrophysics::Galaxy Astrophysics, Line (formation), Physics, methods: statistical, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Millimeter, Astrophysics - Instrumentation and Methods for Astrophysics, Astro-ph.GA, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: 27 pags., 19 figs., 4 tabs., Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous trace molecules are effective from ground based telescopes, but the relationships between the emission of one molecular line and the H2 column density (NH2) is non-linear and sensitive to excitation conditions, optical depths, abundance variations due to the underlying physico-chemistry. We aim to use multi-molecule line emission to infer NH2 from radio observations. We propose a data-driven approach to determine NH2 from radio molecular line observations. We use supervised machine learning methods (Random Forests) on wide-field hyperspectral IRAM-30m observations of the Orion B molecular cloud to train a predictor of NH2, using a limited set of molecular lines as input, and the Herschel-based dust-derived NH2 as ground truth output. For conditions similar to the Orion B molecular cloud, we obtain predictions of NH2 within a typical factor of 1.2 from the Herschel-based estimates. An analysis of the contributions of the different lines to the predictions show that the most important lines are $^{13}$CO(1-0), $^{12}$CO(1-0), C$^{18}$O(1-0), and HCO$^+$(1-0). A detailed analysis distinguishing between diffuse, translucent, filamentary, and dense core conditions show that the importance of these four lines depends on the regime, and that it is recommended to add the N$_2$H$^+$(1-0) and CH$_3$OH(20-10) lines for the prediction of NH2 in dense core conditions. This article opens a promising avenue to directly infer important physical parameters from the molecular line emission in the millimeter domain. The next step will be to try to infer several parameters simultaneously (e.g., NH2 and far-UV illumination field) to further test the method. [Abridged], This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.
Published: 2020

14. Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM III. Elemental depletion and shortcomings of the current physico-chemical models

Author: Wasim Iqbal, M. Ruaud, Ian A. Bonnell, Pierre Gratier, J. P. Melisse, Valentine Wakelam, AMOR 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Research Council, and University of St Andrews. School of Physics and Astronomy
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, Abundance (chemistry), NDAS, Thermal desorption, FOS: Physical sciences, ISM: atoms, evolution [ISM], 01 natural sciences, ISM: abundances, Ion, ISM: evolution, Phase (matter), 0103 physical sciences, QB Astronomy, Molecule, QD, 010303 astronomy & astrophysics, QC, Astrophysics::Galaxy Astrophysics, QB, 0105 earth and related environmental sciences, abundances [ISM], Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], astrochemistry, Astronomy and Astrophysics, QD Chemistry, Astrophysics - Astrophysics of Galaxies, Interstellar medium, QC Physics, atoms [ISM], 13. Climate action, Space and Planetary Science, Chemisorption, Chemical physics, Astrophysics of Galaxies (astro-ph.GA)
Abstract: We present a study of the elemental depletion in the interstellar medium. We combined the results of a Galatic model describing the gas physical conditions during the formation of dense cores with a full-gas-grain chemical model. During the transition between diffuse and dense medium, the reservoirs of elements, initially atomic in the gas, are gradually depleted on dust grains (with a phase of neutralisation for those which are ions). This process becomes efficient when the density is larger than 100~cm$^{-3}$. If the dense material goes back into diffuse conditions, these elements are brought back in the gas-phase because of photo-dissociations of the molecules on the ices followed by thermal desorption from the grains. Nothing remains on the grains for densities below 10~cm$^{-3}$ or in the gas-phase in a molecular form. One exception is chlorine, which is efficiently converted at low density. Our current gas-grain chemical model is not able to reproduce the depletion of atoms observed in the diffuse medium except for Cl which gas abundance follows the observed one in medium with densities smaller than 10~cm$^{-3}$. This is an indication that crucial processes (involving maybe chemisorption and/or ice irradiation profoundly modifying the nature of the ices) are missing., Accepted for publication in MNRAS
Published: 2020

15. Learning from model grids: Tracers of the ionization fraction in the ISM

Author: Emeric Bron, Evelyne Roueff, Maryvonne Gerin, Jérôme Pety, Pierre Gratier, Franck Le Petit, Viviana Guzman, Jan Orkisz, Victor de Souza Magalhaes, Mathilde Gaudel, Pierre Palud, Lucas Einig, Sébastien Bardeau, Pierre Chainais, Jocelyn Chanussot, Javier Goicoechea, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, François Levrier, Darek Lis, Harvey Liszt, Karin Öberg, Nicolas Peretto, Antoine Roueff, Albrecht Sievers, Pierre-Antoine Thouvenin, and Pascal Tremblin
Abstract: The ionization fraction in neutral interstellar clouds is a key physical parameter controlling multiple physical and chemical processes, and varying by orders of magnitude from the UV irradiated surface of the cloud to its cosmic-ray dominated central regions. Traditional observational tracers of the ionization fraction, which mostly rely on deuteration ratios of molecules like HCO+, suffer from the fact that the deuterated molecules are only detected in a tiny fraction of a given Giant Molecular Cloud (GMC). In [1], we propose a machine learning-based, semi-automatic method to search in a large dataset of astrochemical model results for new tracers of the ionization fraction, and propose several new tracers relevant in different ranges of physical conditions.
Published: 2022

16. Experimental postseismic recovery of fractured rocks assisted by calcite sealing

Author: Mai-Linh Doan, Franciscus M. Aben, Jean-Pierre Gratier, and François Renard
Subjects: Calcite, 010504 meteorology & atmospheric sciences, Drop (liquid), 010502 geochemistry & geophysics, Microstructure, 01 natural sciences, chemistry.chemical_compound, Permeability (earth sciences), Geophysics, chemistry, Fluid chemistry, Fluid dynamics, General Earth and Planetary Sciences, Geotechnical engineering, Pressure solution, Petrology, Dissolution, Geology, 0105 earth and related environmental sciences
Abstract: Postseismic recovery within fault damage zones involves slow healing of coseismic fractures leading to permeability reduction and strength increase with time. To better understand this process, experiments were performed by long-term fluid percolation with calcite precipitation through predamaged quartz-monzonite samples subjected to upper crustal conditions of stress and temperature. This resulted in a P wave velocity recovery of 50% of its initial drop after 64 days. In contrast, the permeability remained more or less constant for the duration of the experiment. Microstructures, fluid chemistry, and X-ray microtomography demonstrate that incipient calcite sealing and asperity dissolution are responsible for the P wave velocity recovery. The permeability is unaffected because calcite precipitates outside of the main flow channels. The highly nonparallel evolution of strength recovery and permeability suggests that fluid conduits within fault damage zones can remain open fluid conduits after an earthquake for much longer durations than suggested by the seismic monitoring of fault healing.
Published: 2017

17. A study of singly deuterated cyclopropenylidene c-C3HD in the protostar IRAS 16293–2422

Author: Liton Majumdar, Pierre Gratier, Emmanuel Caux, Valentine Wakelam, Ines Andron, AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNRS INSU, UMR 5187, F-31028 Toulouse 4, France, UMR 5187 Toulouse, Univ Toulouse UPS, Ctr Etud Spatiale Rayonnements, F-31062 Toulouse 9, France, and Centre Etud Spatiale Rayonnements Toulouse
Subjects: Physics, Cyclopropenylidene, Astrochemistry, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, IRAM 30m telescope, Galaxy, chemistry.chemical_compound, Deuterium, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, Isotopologue, 010303 astronomy & astrophysics, Excitation
Abstract: Cyclic-C3HD (c-C3HD) is a singly deuterated isotopologue of c-C3H2, which is one of the most abundant and widespread molecules in our Galaxy. We observed IRAS 16293-2422 in the 3 mm band with a single frequency setup using the EMIR heterodyne 3 mm receiver of the IRAM 30m telescope. We observed seven lines of c-C3HD and three lines of c-C3H2. Observed abundances are compared with astrochemical simulations using the NAUTILUS gas-grain chemical model. Our results clearly show that c-C3HD can be used as an important supplement for studying chemistry and physical conditions for cold environments. Assuming that the size of the protostellar envelope is 3000 AU and same excitation temperatures for both c-C3H2 and c-C3HD, we obtain a deuterium fraction of $14_{-3}^{+4}\%$., Accepted for publication in MNRAS
Published: 2017

18. Revised mass-radius relationships for water-rich rocky planets more irradiated than the runaway greenhouse limit

Author: Franck Selsis, Nathan Hara, Pierre Gratier, David Ehrenreich, Martin Turbet, Emeline Bolmont, Christophe Lovis, Jérémy Leconte, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève (UNIGE), AMOR 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and ECLIPSE 2020
Subjects: Water mass, 010504 meteorology & atmospheric sciences, planets and satellites: individual: TRAPPIST-1, FOS: Physical sciences, Astrophysics, 01 natural sciences, Atmosphere, planets and satellites: terrestrial planets, Physics - Geophysics, Planet, 0103 physical sciences, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, 0105 earth and related environmental sciences, Physics, planets and satellites: atmospheres, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Planetary core, planets and satellites: composition, Astronomy and Astrophysics, Radius, Mass ratio, planets and satellites: interiors, Geophysics (physics.geo-ph), Physics - Atmospheric and Oceanic Physics, Orders of magnitude (time), 13. Climate action, Space and Planetary Science, Atmospheric and Oceanic Physics (physics.ao-ph), Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: Mass-radius relationships for water-rich rocky planets are usually calculated assuming most water is present in condensed (either liquid or solid) form. Planet density estimates are then compared to these mass-radius relationships, even when these planets are more irradiated than the runaway greenhouse irradiation limit (around 1.1~times the insolation at Earth for planets orbiting a Sun-like star), for which water has been shown to be unstable in condensed form and would instead form a thick H2O-dominated atmosphere. Here we use the LMD Generic numerical climate model to derive new mass-radius relationships appropriate for water-rich rocky planets that are more irradiated than the runaway greenhouse irradiation limit, meaning planets endowed with a steam, water-dominated atmosphere. For a given water-to-rock mass ratio, these new mass-radius relationships lead to planet bulk densities much lower than calculated when water is assumed to be in condensed form. In other words, using traditional mass-radius relationships for planets that are more irradiated than the runaway greenhouse irradiation limit tends to dramatically overestimate -- possibly by several orders of magnitude -- their bulk water content. In particular, this result applies to TRAPPIST-1 b, c, and d, which can accommodate a water mass fraction of at most 2, 0.3 and 0.08 %, respectively, assuming planetary core with a terrestrial composition. In addition, we show that significant changes of mass-radius relationships (between planets less and more irradiated than the runaway greenhouse limit) can be used to remove bulk composition degeneracies in multiplanetary systems such as TRAPPIST-1. Finally, we provide an empirical formula for the H2O steam atmosphere thickness which can be used to construct mass-radius relationships for any water-rich, rocky planet more irradiated than the runaway greenhouse irradiation threshold., Final version published in A&A. (small typos in Tables 1 and 2 have been corrected)
Published: 2019

19. A Fully Bayesian Approach For Inferring Physical Properties With Credibility Intervals From Noisy Astronomical Data

Author: Victor de Souza Magalhaes, Javier R. Goicoechea, Annie Hughes, Fracois Levrier, Viviana V. Guzmán, Pascal Tremblin, M. Gaudel, Karin I. Öberg, Evelyne Roueff, Antoine Roueff, Pierre Chainais, Maryvonne Gerin, Sébastien Bardeau, Jocelyn Chanussot, David Languignon, Albrecht Sievers, Franck Petit, Harvey S. Listz, Pierre Gratier, Maxime Vono, Jérôme Pety, Sébastien Bourguignon, Jan H. Orkisz, Nicolas Peretto, Emeric Bron, Jacques Le Bourlot, Jouni Kainulainen, Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Chalmers University of Technology [Göteborg], Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), Umeå University, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, Université Paul Cézanne - Aix-Marseille 3, Instituto de RadioAstronomía Milimétrica (IRAM), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Departement d'Astrophysique Extragalactique et de Cosmologie (DAEC), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire des Sciences du Numérique de Nantes (LS2N), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), Département Images et Signal (GIPSA-DIS), Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), National Radio Astronomy Observatory (NRAO)-European Southern Observatory (ESO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS-PSL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Nantes (ECN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Pointwise, [PHYS]Physics [physics], Computer science, Molecular cloud, Bayesian probability, Interstellar cloud, Estimator, 02 engineering and technology, 01 natural sciences, Physical conditions, Markov chain Monte Carlo, 13. Climate action, 0103 physical sciences, Radioastronomy, 0202 electrical engineering, electronic engineering, information engineering, Maximum a posteriori estimation, Probability distribution, 020201 artificial intelligence & image processing, Approximate Bayesian computation, [INFO]Computer Science [cs], Statistical physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: International audience; The atoms and molecules of interstellar clouds emit photons when passing from an excited state to a lower energy state. The resulting emission lines can be detected by telescopes in the different wavelength domains (radio, infrared, visible, UV...). Through the excitation and chemical conditions they reveal, these lines provide key constraints on the local physical conditions reigning in giant molecular clouds (GMCs), which constitute the birthplace of stars in galaxies. Inferring these physical conditions from observed maps of GMCs using complex astrophysical models of these regions remains a complicated challenge due to potentially degenerate solutions and widely varying signal-to-noise ratios over the map. We propose a Bayesian framework to infer the probability distributions associated to each of these physical parameters, taking a spatial smoothness prior into account to tackle the challenge of low signal-to-noise ratio regions of the observed maps. A numerical astrophysical model of the cloud is involved in the likelihood within an approximate Bayesian computation (ABC) method. This enables to both infer pointwise estimators (e.g., minimum mean square or maximum a posteriori) and quantify the uncertainty associated to the estimation process. The benefits of the proposed approach are illustrated based on noisy synthetic observation maps.
Published: 2019

20. Oxygen fractionation in dense molecular clouds

Author: Pablo Riviere-Marichalar, Pierre Gratier, Jérôme Pety, Valentine Wakelam, Asunción Fuente, Viviana V. Guzmán, Nuria Marcelino, Marcelino Agúndez, Kevin M. Hickson, E. Roueff, Jean-Christophe Loison, Javier R. Goicoechea, Aurore Bacmann, Maryvonne Gerin, José Cernicharo, Franck Le Petit, Centre National de la Recherche Scientifique (France), Université de Bordeaux, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Max Planck Society, Instituto Geográfico Nacional (España), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Departement d'Astrophysique Extragalactique et de Cosmologie (DAEC), Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], chemistry.chemical_element, FOS: Physical sciences, Fractionation, 7. Clean energy, 01 natural sciences, Oxygen, ISM: clouds, ISM: abundances, Article, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, abundances [ISM], Physics, [PHYS]Physics [physics], astrochemistry [Physical Data and Processes], 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Sulfur, Astrophysics - Astrophysics of Galaxies, Physical Data and Processes: astrochemistry, Oxygen atom, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: 22 pags., 5 figs., We have developed the first gas-grain chemical model for oxygen fractionation (also including sulphur fractionation) in dense molecular clouds, demonstrating that gas-phase chemistry generates variable oxygen fractionation levels, with a particularly strong effect for NO, SO, O, and SO. This large effect is due to the efficiency of the neutral O + NO, O + SO, and O + O exchange reactions. The modelling results were compared to new and existing observed isotopic ratios in a selection of cold cores. The good agreement between model and observations requires that the gas-phase abundance of neutral oxygen atoms is large in the observed regions. The SO/SO ratio is predicted to vary substantially over time, showing that it can be used as a sensitive chemical proxy for matter evolution in dense molecular clouds., This work was supported by the program “Physique et Chimie du Milieu Interstellaire” (PCMI) funded by CNRS and CNES. VW researches are funded by the ERC Starting Grant (3DICE, grant agreement 336474). Computer time was provided by the Pôle Modélisation HPC facilities of the Institut des Sciences Moléculaires UMR 5255 CNRS − Université de Bordeaux, co-funded by the Nouvelle Aquitaine region. M.A., N.M., J.C. and J.R.C. thank the Spanish MICIU for funding support under grants AYA2016-75066-C2-1-P and AYA2017-85111-P, and the European Research Council for support under grant ERC2013-Syg-610256-NANOCOSMOS. M.A. also acknowledges funding support from the Ramón y Cajal programme of Spanish MICIU (RyC-2014-16277). IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Published: 2019

21. Influence of galactic arm scale dynamics on the molecular composition of the cold and dense ISM – II. Molecular oxygen abundance

Author: Ian A. Bonnell, Pierre Gratier, M. Ruaud, Valentine Wakelam, AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and European Project: 336474,EC:FP7:ERC,ERC-2013-StG,3DICE(2013)
Subjects: Astrochemistry, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], chemistry.chemical_element, FOS: Physical sciences, Scale (descriptive set theory), Astrophysics, 7. Clean energy, 01 natural sciences, Oxygen, Smoothed-particle hydrodynamics, Abundance (ecology), 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, 010308 nuclear & particles physics, Dynamics (mechanics), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Molecular oxygen
Abstract: Molecular oxygen has been the subject of many observational searches as chemical models predicted it to be a reservoir of oxygen. Although it has been detected in two regions of the interstellar medium, its rarity is a challenge for astrochemical models. In this paper, we have combined the physical conditions computed with smoothed particle hydrodynamics (SPH) simulations with our full gas-grain chemical model Nautilus, to study the predicted O2 abundance in interstellar material forming cold cores. We thus follow the chemical evolution of gas and ices in parcels of material from the diffuse interstellar conditions to the cold dense cores. Most of our predicted O2 abundances are below 1e-8 (with respect to the total proton density) and the predicted column densities in simulated cold cores is at maximum a few 1e14 cm-2, in agreement with the non detection limits. This low O2 abundance can be explained by the fact that, in a large fraction of the interstellar material, the atomic oxygen is depleted onto the grain surface (and hydrogenated to form H2O) before O2 can be formed in the gas-phase and protected from UV photo-dissociations. We could achieve this result only because we took into account the full history of the evolution of the physical conditions from the diffuse medium to the cold cores., Accepted for publication in MNRAS
Published: 2019

22. A dynamically young, gravitationally stable network of filaments in Orion B

Author: François Levrier, Nicolas Peretto, David Languignon, Javier R. Goicoechea, Harvey S. Liszt, Pierre Gratier, Viviana V. Guzmán, Pascal Tremblin, Maryvonne Gerin, Franck Le Petit, Emeric Bron, Jan H. Orkisz, Karin I. Öberg, Albrecht Sievers, Sébastien Bardeau, Annie Hughes, Evelyne Roueff, Jérôme Pety, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, MIS, Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), Umeå University, Instituto de RadioAstronomía Milimétrica (IRAM), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Paris-Saclay, Istituto Nazionale di Astrofisica, European Commission, Ministerio de Economía y Competitividad (España), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Smithsonian Institution-Harvard University [Cambridge], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Harvard University [Cambridge]-Smithsonian Institution, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: ISM: individual objects: Orion B, media_common.quotation_subject, ISM: structure, Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: clouds, Protein filament, 0103 physical sciences, Gravitational collapse, Supersonic speed, data analysis [Methods], education, 010303 astronomy & astrophysics, media_common, Physics, ISM: kinematics and dynamics, education.field_of_study, radio lines: ISM, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, methods: data analysis, Astrophysics - Astrophysics of Galaxies, ISM [Radio lines], [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], individual objects: Orion B [ISM], kinematics and dynamics [ISM], Stars, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), structure [ISM], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: Context. Filaments are a key step on the path that leads from molecular clouds to star formation. However, their characteristics, for instance their width, are heavily debated and the exact processes that lead to their formation and fragmentation into dense cores still remain to be fully understood. Aims. We aim at characterising the mass, kinematics, and stability against gravitational collapse of a statistically significant sample of filaments in the Orion B molecular cloud, which is renown for its very low star formation efficiency. Methods. We characterised the gas column densities and kinematics over a field of 1.9 deg2 , using C18O (J = 1−0) data from the IRAM 30 m large programme ORION-B at angular and spectral resolutions of 23.5 00 and 49.5 kHz, respectively. Using two different Hessian-based filters, we extracted and compared two filamentary networks, each containing over 100 filaments. Results. Independent of the extraction method, the filament networks have consistent characteristics. The filaments have widths of ∼0.12 ± 0.04 pc and show a wide range of linear (∼1−100 M pc−1 ) and volume densities (∼2 × 103−2 × 105 cm−3 ). Compared to previous studies, the filament population is dominated by low-density, thermally sub-critical structures, suggesting that most of the identified filaments are not collapsing to form stars. In fact, only ∼1% of the Orion B cloud mass covered by our observations can be found in super-critical, star-forming filaments, explaining the low star formation efficiency of the region. The velocity profiles observed across the filaments show quiescence in the centre and coherency in the plane of the sky, even though these profiles are mostly supersonic. Conclusions. The filaments in Orion B apparently belong to a continuum which contains a few elements comparable to already studied star-forming filaments, for example in the IC 5146, Aquila or Taurus regions, as well as many lower density, gravitationally unbound structures. This comprehensive study of the Orion B filaments shows that the mass fraction in super-critical filaments is a key factor in determining star formation efficiency., 22 pags., 15 figs., 4 tabs., 2 apps., This research has made use of data from the Herschel Gould Belt Survey (HGBS) project (http://gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). This work was supported by the CNRS/CNES programme “Physique et Chimie du Milieu Interstellaire” (PCMI). We thank the CIAS for its hospitality during the three workshops devoted to this project. N.P. wishes to acknowledge support from STFC under grant number ST/N000706/1. P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. J.R.G. thanks the Spanish MINECO for funding support under grant AYA2017-85111-P.
Published: 2019

23. Small-scale physical and chemical structure of diffuse and translucent molecular clouds along the line of sight to Sgr B2

Author: A. Giannetti, Holger S. P. Müller, Robin T. Garrod, Arnaud Belloche, Dario Colombo, V. Thiel, Benjamin Winkel, Helmut Wiesemeyer, Karl M. Menten, Pierre Gratier, Geoscience Centre (GZG), Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max-Planck-Institut für Radioastronomie (MPIFR), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics, The Ohio State University, and Ohio State University [Columbus] (OSU)
Subjects: Physics, Astrochemistry, Line-of-sight, Spiral galaxy, Opacity, 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Submillimeter Array, Astrophysics - Astrophysics of Galaxies, Spectral line, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Isotopologue, 010303 astronomy & astrophysics
Abstract: The diffuse and translucent molecular clouds traced in absorption along the line of sight to strong background sources have so far been investigated mainly in the spectral domain because of limited angular resolution or small sizes of the background sources. We aim to resolve and investigate the spatial structure of molecular clouds traced by several molecules detected in absorption along the line of sight to SgrB2(N). We have used spectral line data from the EMoCA survey performed with ALMA, taking advantage of the high sensitivity and angular resolution. We identify, on the basis of the spectral analysis of c-C3H2 across the field of view, 15 main velocity components along the line of sight to SgrB2(N) and several components in the envelope of SgrB2. The c-C3H2 column densities reveal two categories of clouds. Clouds in Category I (3 kpc arm, 4 kpc arm, and some GC clouds) have smaller c-C3H2 column densities, smaller linewidths, and smaller widths of their column density PDFs than clouds in Category II (Scutum arm, Sgr arm, and other GC clouds). To investigate the spatial structure we derive opacity maps for the following molecules: c-C3H2, H13CO+, 13CO, HNC, HN13C, HC15N, CS, C34S, 13CS, SiO, SO, and CH3OH. These maps reveal that most molecules trace relatively homogeneous structures that are more extended than the field of view defined by the background continuum emission (about 15", that is 0.08-0.6pc depending on the distance). SO and SiO show more complex structures with smaller clumps of size ~5-8". Our analysis suggests that the driving of the turbulence is mainly solenoidal in the investigated clouds. On the basis of HCO+, we conclude that most line-of-sight clouds towards SgrB2 are translucent, including all clouds where complex organic molecules were recently detected. We also conclude that CCH and CH are good probes of H2 in both diffuse and translucent clouds., Accepted for publication in A&A, 83 pages, 106 figures
Published: 2019

24. Abundances of sulphur molecules in the Horsehead nebula. First NS+ detection in a photodissociation region

Author: R. Le Gal, Javier R. Goicoechea, Evelyne Roueff, Jérôme Pety, Viviana V. Guzmán, Maryvonne Gerin, Pablo Riviere-Marichalar, Pierre Gratier, Valentine Wakelam, Asunción Fuente, Jean-Christophe Loison, Observatorio Astronómico Nacional (OAN), oan, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ministerio de Economía y Competitividad (España), European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Ctr Astrobiol CSIC INTA, Lab Astofis Mol, Madrid 28850, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars: formation, FOS: Physical sciences, Context (language use), Astrophysics, Photodissociation region, 01 natural sciences, Article, ISM: abundances, Abundance (ecology), low-mass [Stars], 0103 physical sciences, Radiative transfer, Stars: low-mass, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), molecules [ISM], formation [Stars], 0105 earth and related environmental sciences, Line (formation), ISM: kinematics and dynamics, Physics, abundances [ISM], Nebula, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Abundance of the chemical elements, 3. Good health, kinematics and dynamics [ISM], Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: 15 pags., 5 figs., 5 tabs., 1 app., Context. Sulphur is one of the most abundant elements in the Universe (S/H ~ 1.3 × 10) and plays a crucial role in biological systems on Earth. The understanding of its chemistry is therefore of major importance. Aims. Our goal is to complete the inventory of S-bearing molecules and their abundances in the prototypical photodissociation region (PDR) the Horsehead nebula to gain insight into sulphur chemistry in UV irradiated regions. Based on the WHISPER (Wide-band High-resolution Iram-30 m Surveys at two positions with Emir Receivers) millimeter (mm) line survey, our goal is to provide an improved and more accurate description of sulphur species and their abundances towards the core and PDR positions in the Horsehead. Methods. The Monte Carlo Markov chain (MCMC) methodology and the molecular excitation and radiative transfer code RADEX were used to explore the parameter space and determine physical conditions and beam-averaged molecular abundances. Results. A total of 13 S-bearing species (CS, SO, SO, OCS, HCS-both ortho and para-HDCS, CS, HCS, SO, HS, SH, NS and NS) have been detected in the two targeted positions. This is the first detection of SO in the Horsehead and the first detection of NS in any PDR. We find a differentiated chemical behaviour between C-S and O-S bearing species within the nebula. The C-S bearing species CS and o-HCS present fractional abundances a factor of > two higher in the core than in the PDR. In contrast, the O-S bearing molecules SO, SO, and OCS present similar abundances towards both positions. A few molecules, SO, NS, and NS, are more abundant towards the PDR than towards the core, and could be considered as PDR tracers. Conclusions. This is the first complete study of S-bearing species towards a PDR. Our study shows that CS, SO, and HS are the most abundant S-bearing molecules in the PDR with abundances of approximately a few 10. We recall that SH, SH, S, and S are not observable at the wavelengths covered by the WHISPER survey. At the spatial scale of our observations, the total abundance of S atoms locked in the detected species is, We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, AYA2017-85111-P and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. J.R.G. thanks the Spanish MCIU for funding support under grant AYA2017-85111-P. This work was supported by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.
Published: 2019

25. Chemical nitrogen fractionation in dense molecular clouds

Author: Jean-Christophe Loison, Kevin M. Hickson, Pierre Gratier, Valentine Wakelam, Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Astrochemistry, 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Molecular cloud, Photodissociation, chemistry.chemical_element, FOS: Physical sciences, Astronomy and Astrophysics, Fractionation, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Nitrogen, Interstellar medium, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Atom, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Cosmic dust
Abstract: Nitrogen-bearing molecules display variable isotopic fractionation levels in different astronomical environments such as in the interstellar medium or in the Solar System. Models of interstellar chemistry are unable to induce nitrogen fraction in cold molecular clouds as exchange reactions for 15N are mostly inefficient. Here, we developed a new gas-grain model for nitrogen fractionation including a thorough search for new nitrogen fractionation reactions and a realistic description of atom depletion onto interstellar dust particles. We show that, while dense molecular cloud gas-phase chemistry alone leads to very low fractionation, 14N atoms are preferentially depleted from the gas-phase due to a mass dependent grain surface sticking rate for atomic nitrogen. However, assuming an elementary 14N/15N ratio of 441 (equal to the solar wind value), our model leads to only low 15N enrichment for all N-containing species synthesized in the gas-phase with predicted 14N/15N ratios in the range 360-400. Higher enrichment levels can neither be explained by this mechanism, nor through chemistry, with two possible explanations. (I) The elementary 14N/15N ratio in the local ISM is smaller, as suggested by the recent work of Romano et al, with an hypothetic 15NNH+ and 15NNH+ depletion due to variation of the electronic recombination rate constant variation with the isotopes. (II) N2 photodissociation leads to variable nitrogen fractionation in diffuse molecular clouds where photons play an important role, which is conserved during dense molecular cloud formation as suggested by the work of Furuya & Aikawa., 21 pages, 3 figures
Published: 2019

26. New constraints on the initial parameters of low-mass star formation from chemical modeling

Author: Audrey Coutens, Thomas H. G. Vidal, Valentine Wakelam, Pierre Gratier, Neil Vaytet, AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon), and École normale supérieure - Lyon (ENS Lyon)
Subjects: Physics, Work (thermodynamics), Astrochemistry, 010308 nuclear & particles physics, Star formation, Chemical process modeling, FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Chemical species, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Low Mass, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The complexity of physico-chemical models of star formation is increasing, with models that take into account new processes and more realistic setups. These models allow astrochemists to compute the evolution of chemical species throughout star formation. Hence, comparing the outputs of such models to observations allows to bring new constraints on star formation. The work presented in this paper is based on the recent public release of a database of radiation hydrodynamical low-mass star formation models. We used this database as physical parameters to compute the time dependent chemical composition of collapsing cores with a 3-phase gas-grain model. The results are analyzed to find chemical tracers of the initial physical parameters of collapse such as the mass, radius, temperature, density, and free-fall time. They are also compared to observed molecular abundances of Class 0 protostars. We find numerous tracers of the initial parameters of collapse, except for the initial mass. More particularly, we find that gas phase CH3CN, NS and OCS trace the initial temperature, while H2CS trace the initial density and free-fall time of the parent cloud. The comparison of our results with a sample of 12 Class 0 low mass protostars allows us to constrain the initial parameters of collapse of low-mass prestellar cores. We find that low-mass protostars are preferentially formed within large cores with radii greater than 20000 au, masses between 2 and 4 Msol, temperatures lower or equal to 15 K, and densities between 6e4 and 2.5e5 part.cm-3, corresponding to free-fall times between 100 and 200 kyrs., Accepted for publication in MNRAS
Published: 2019

27. Methyl cyanide (CH3CN) and propyne (CH3CCH) in the low-mass protostar IRAS 16293–2422

Author: Thomas H. G. Vidal, Valentine Wakelam, Jean-Christophe Loison, Liton Majumdar, Audrey Coutens, Ines Andron, Pierre Gratier, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), and Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Astrochemistry, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Cyanide, FOS: Physical sciences, Astrophysics, Propyne, 7. Clean energy, 01 natural sciences, Mantle (geology), law.invention, Telescope, chemistry.chemical_compound, law, 0103 physical sciences, Radiative transfer, Protostar, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Low Mass
Abstract: Methyl cyanide (CH3CN) and propyne (CH3CCH) are two molecules commonly used as gas thermometers for interstellar gas. They are detected in several astrophysical environments and in particular towards protostars. Using data of the low-mass protostar IRAS 16293-2422 obtained with the IRAM 30m single-dish telescope, we constrained the origin of these two molecules in the envelope of the source. The line shape comparison and the results of a radiative transfer analysis both indicate that the emission of CH3CN arises from a warmer and inner region of the envelope than the CH3CCH emission. We compare the observational results with the predictions of a gas-grain chemical model. Our model predicts a peak abundance of CH3CCH in the gas-phase in the outer part of the envelope, at around 2000 au from the central star, which is relatively close to the emission size derived from the observations. The predicted CH3CN abundance only rises at the radius where the grain mantle ices evaporate, with an abundance similar to the one derived from the observations.
Published: 2018

28. Dynamic fracturing by successive coseismic loadings leads to pulverization in active fault zones

Author: Thomas M. Mitchell, F. M. Aben, Thierry Reuschlé, François Renard, Renaud Toussaint, Michele Fondriest, Mai-Linh Doan, and Jean-Pierre Gratier
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Petrophysics, Active fault, Split-Hopkinson pressure bar, Fault (geology), Strain rate, 010502 geochemistry & geophysics, 01 natural sciences, Geophysics, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Perpendicular, Earthquake rupture, Geotechnical engineering, Elastic modulus, Geology, 0105 earth and related environmental sciences
Abstract: Previous studies show that pulverized rocks observed along large faults can be created by single high-strain rate loadings in the laboratory, provided that the strain rate is higher than a certain pulverization threshold. Such loadings are analogous to large seismic events. In reality, pulverized rocks have been subject to numerous seismic events rather than one single event. Therefore, the effect of successive “milder” high-strain rate loadings on the pulverization threshold is investigated by applying loading conditions below the initial pulverization threshold. Single and successive loading experiments were performed on quartz-monzonite using a Split Hopkinson Pressure Bar apparatus. Damage-dependent petrophysical properties and elastic moduli were monitored by applying incremental strains. Furthermore, it is shown that the pulverization threshold can be reduced by successive “milder” dynamic loadings from strain rates of ~180 s−1 to ~90 s−1. To do so, it is imperative that the rock experiences dynamic fracturing during the successive loadings prior to pulverization. Combined with loading conditions during an earthquake rupture event, the following generalized fault damage zone structure perpendicular to the fault will develop: furthest from the fault plane, there is a stationary outer boundary that bounds a zone of dynamically fractured rocks. Closer to the fault, a pulverization boundary delimits a band of pulverized rock. Consecutive seismic events will cause progressive broadening of the band of pulverized rocks, eventually creating a wider damage zone observed in mature faults.
Published: 2016

29. Stylolites: A review

Author: Jean-Pierre Gratier, Martin Ebner, François Renard, Patrick Baud, Renaud Toussaint, Einat Aharonov, Daniel Koehn, Alexandra Rolland, Institut de physique du globe de Strasbourg (IPGS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Tectonophysics, Institute of Geosciences, Johannes Gutenberg University, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Norges Forskningsråd, 262644, EU FP7 ITN FlowTrans network, CNRS INSU ALEAS, NEEDS MIPOR, University of Strasbourg IDEX, LIA France-Norway D-FFRACT, European Project: 316889,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,FLOWTRANS(2013), and Johannes Gutenberg - Universität Mainz (JGU)
Subjects: 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], review, [SDU.STU.PE]Sciences of the Universe [physics]/Earth Sciences/Petrography, FOS: Physical sciences, Condensed Matter - Soft Condensed Matter, structural geology, 010502 geochemistry & geophysics, 01 natural sciences, Physics - Geophysics, physico-chemistry, stress, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Anisotropy, Petrology, Scaling, 0105 earth and related environmental sciences, Stress concentration, marker, Condensed Matter - Materials Science, pressure-solution, stylolite, paleostress, Materials Science (cond-mat.mtrl-sci), Geology, modeling, experiments, Geophysics (physics.geo-ph), Tectonics, Stylolite, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Soft Condensed Matter (cond-mat.soft), Sedimentary rock, Pressure solution, Shear zone, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract: International audience; Highlights:. Stylolite formation depends on rock composition and structure, stress and fluids.. Stylolite geometry, fractal and self-affine properties, network structure, are investigated.. The experiments and physics-based numerical models for their formation are reviewed.. Stylolites can be used as markers of strain, paleostress orientation and magnitude.. Stylolites impact transport properties, as function of maturity and flow direction.AbstractStylolites are ubiquitous geo-patterns observed in rocks in the upper crust, from geological reservoirs in sedimentary rocks to deformation zones, in folds, faults, and shear zones. These rough surfaces play a major role in the dissolution of rocks around stressed contacts, the transport of dissolved material and the precipitation in surrounding pores. Consequently, they play an active role in the evolution of rock microstructures and rheological properties in the Earth’s crust. They are observed individually or in networks, in proximity to fractures and joints, and in numerous geological settings. This review article deals with their geometrical and compositional characteristics and the factors leading to their genesis. The main questions this review focuses on are the following: How do they form? How can they be used to measure strain and formation stress? How do they control fluid flow in the upper crust?Geometrically, stylolites have fractal roughness, with fractal geometrical properties exhibiting typically three scaling regimes: a self-affine scaling with Hurst exponent 1.1+/-0.1 at small scale (up to tens or hundreds of microns), another one with Hurst exponent around 0.5 to 0.6 at intermediate scale (up to millimeters or centimeters), and in the case of sedimentary stylolites, a flat scaling at large scale. More complicated anisotropic scaling (scaling laws depending of the direction of the profile considered) is found in the case of tectonic stylolites. We report models based on first principles from physical chemistry and statistical physics, including a mechanical component for the free-energy associated with stress concentrations, and a precise tracking of the influence of grain-scale heterogeneities and disorder on the resulting (micro)structures. Experimental efforts to reproduce stylolites in the laboratory are also reviewed. We show that although micrometer-size stylolite teeth are obtained in laboratory experiments, teeth deforming numerous grains have not yet been obtained experimentally, which is understandable given the very long formation time of such geometries. Finally, the applications of stylolites as strain and stress markers, to determine paleostress magnitude are reviewed. We show that the scalings in stylolite heights and the crossover scale between these scalings can be used to determine the stress magnitude (its scalar value) perpendicular to the stylolite surface during the stylolite formation, and that the stress anisotropy in the stylolite plane can be determined for the case of tectonic stylolites. We also show that the crossover between medium (millimetric) scales and large (pluricentimetric) scales, in the case of sedimentary stylolites, provides a good marker for the total amount of dissolution, which is still valid even when the largest teeth start to dissolve – which leads to the loss of information, since the total deformation is not anymore recorded in a single marker structure. We discuss the impact of the stylolites on the evolution of the transport properties of the hosting rock, and show that they promote a permeability increase parallel to the stylolites, whereas their effect on the permeability transverse to the stylolite can be negligible, or may reduce the permeability, depending on the development of the stylolite.
Published: 2018

30. Rotation of molecular clouds in M 51

Author: Sharon E. Meidt, Pierre Gratier, Dario Colombo, Erik Rosolowsky, Jonathan Braine, Eva Schinnerer, Annie Hughes, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and AMOR 2020
Subjects: galaxies: spiral, individual: M 51 [galaxies], [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astrophysics, Rotation, ISM: clouds, 01 natural sciences, Gravitational potential, 0103 physical sciences, 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, Galaxy rotation curve, Physics, stars: formation, formation [stars], Spiral galaxy, ISM [galaxies], 010308 nuclear & particles physics, Molecular cloud, Retrograde motion, Astronomy and Astrophysics, galaxies: individual: M 51, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Galaxy, Rotational energy, spiral [galaxies], Physics and Astronomy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), clouds [ISM], galaxies: ISM
Abstract: The grand-design spiral galaxy M~51 was observed at 40pc resolution in CO(1--0) by the PAWS project. A large number of molecular clouds were identified and we search for velocity gradients in two high signal-to-noise subsamples, containing 682 and 376 clouds. The velocity gradients are found to be systematically prograde oriented, as was previously found for the rather flocculent spiral M~33. This strongly supports the idea that the velocity gradients reflect cloud rotation, rather than more random dynamical forces, such as turbulence. Not only are the gradients prograde, but their $\frac{\partial v}{\partial x}$ and $\frac{\partial v}{\partial y}$ coefficients follow galactic shear in sign, although with a lower amplitude. No link is found between the orientation of the gradient and the orientation of the cloud. The values of the cloud angular momenta appear to be an extension of the values noted for galactic clouds despite the orders of magnitude difference in cloud mass. Roughly 30\% of the clouds show retrograde velocity gradients. For a strictly rising rotation curve, as in M~51, gravitational contraction would be expected to yield strictly prograde rotators within an axisymmetric potential. In M~51, the fraction of retrograde rotators is found to be higher in the spiral arms than in the disk as a whole. Along the leading edge of the spiral arms, a majority of the clouds are retrograde rotators. While this work should be continued on other nearby galaxies, the M~33 and M~51 studies have shown that clouds rotate and that they rotate mostly prograde, although the amplitudes are not such that rotational energy is a significant support mechanism against gravitation. In this work, we show that retrograde rotation is linked to the presence of a spiral gravitational potential., Comment: Accepted by Astronomy and Astrophysics
Published: 2019

31. First Detection of Interstellar S

Author: Asunción, Fuente, Javier R, Goicoechea, Jerome, Pety, Romane, Le Gal, Rafael, Martín-Doménech, Pierre, Gratier, Viviana, Guzmán, Evelyne, Roueff, Jean Christophe, Loison, Guillermo M, Muñoz Caro, Valentine, Wakelam, Maryvonne, Gerin, Pablo, Riviere-Marichalar, and Thomas, Vidal
Subjects: Article
Abstract: We present the first detection of gas phase S2H in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed S2H abundance is ~5×10−11, only a factor 4-6 lower than that of the widespread H2S molecule. H2S and S2H are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the H2S and S2H photodesorption yields. The obtained values are ~1.2×10−3 and
Published: 2018

32. Detection of HOCO+ in the protostar IRAS 16293-2422

Author: Emmanuel Caux, Pierre Gratier, Karen Willacy, Michael E. Ressler, Valentine Wakelam, Liton Majumdar, AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Heterodyne, Astrochemistry, 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, 7. Clean energy, Astrophysics - Astrophysics of Galaxies, IRAM 30m telescope, Methods statistical, Dipole, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Protostar, Millimeter, Emission spectrum, 010303 astronomy & astrophysics
Abstract: The protonated form of CO2, HOCO+, is assumed to be an indirect tracer of CO2 in the millimeter/submillimeter regime since CO2 lacks a permanent dipole moment. Here, we report the detection of two rotational emission lines (4 0,4-3 0,3) and (5 0,5-4 0,4) of HOCO+ in IRAS 16293-2422. For our observations, we have used EMIR heterodyne 3 mm receiver of the IRAM 30m telescope. The observed abundance of HOCO+ is compared with the simulations using the 3-phase NAUTILUS chemical model. Implications of the measured abundances of HOCO+ to study the chemistry of CO2 ices using JWST-MIRI and NIRSpec are discussed as well., Comment: Accepted for publication in MNRAS on March 13th, 7 pages, 3 figures, 2 tables
Published: 2018

33. Properties and rotation of molecular clouds in M 33

Author: Edvige Corbelli, Jonathan Braine, Karl Schuster, Pierre Gratier, Erik Rosolowsky, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), AMOR 2020, Institut de RadioAstronomie Millimétrique (IRAM), and Centre National de la Recherche Scientifique (CNRS)
Subjects: Rotation period, Metallicity, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Rotation, 01 natural sciences, ISM: clouds, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, stars: formation, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, Escape velocity, Astrophysics - Astrophysics of Galaxies, Galaxy, galaxies: individual: M 33, ISM: molecules, Rotational energy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Local Group, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], galaxies: ISM
Abstract: The sample of 566 molecular clouds identified in the CO(2--1) IRAM survey covering the disk of M~33 is explored in detail.The clouds were found using CPROPS and were subsequently catalogued in terms of their star-forming properties as non-star-forming (A), with embedded star formation (B), or with exposed star formation C.We find that the size-linewidth relation among the M~33 clouds is quite weak but, when comparing with clouds in other nearby galaxies, the linewidth scales with average metallicity.The linewidth and particularly the line brightness decrease with galactocentric distance.The large number of clouds makes it possible to calculate well-sampled cloud mass spectra and mass spectra of subsamples.As noted earlier, but considerably better defined here, the mass spectrum steepens (i.e. higher fraction of small clouds) with galactocentric distance.A new finding is that the mass spectrum of A clouds is much steeper than that of the star-forming clouds.Further dividing the sample, this difference is strong at both large and small galactocentric distances and the A vs C difference is a stronger effect than the inner/outer disk difference in mass spectra.Velocity gradients are identified in the clouds using standard techniques.The gradients are weak and are dominated by prograde rotation; the effect is stronger for the high signal-to-noise clouds.A discussion of the uncertainties is presented.The angular momenta are low but compatible with at least some simulations.The cloud and galactic gradients are similar; the cloud rotation periods are much longer than cloud lifetimes and comparable to the galactic rotation period.The rotational kinetic energy is 1-2\% of the gravitational potential energy and the cloud edge velocity is well below the escape velocity, such that cloud-scale rotation probably has little influence on the evolution of molecular clouds., Accepted for publication in Astronomy and Astrophysics, 11 pages
Published: 2018

34. Triggering the formation of the supergiant H II region NGC 604 in M33

Author: Kisetsu Tsuge, Kazuyuki Muraoka, Pierre Gratier, Kengo Tachihara, Hidetoshi Sano, Rie E. Miura, Yasuo Fukui, AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Very large array, Physics, H II region, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 010308 nuclear & particles physics, Molecular cloud, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Cluster (physics), Supergiant, 010303 astronomy & astrophysics, Line (formation)
Abstract: Formation mechanism of a supergiant H II region NGC 604 is discussed in terms of collision of H I clouds in M33. An analysis of the archival H I data obtained with the Very Large Array (VLA) reveals complex velocity distributions around NGC 604. The H I clouds are composed of two velocity components separated by ~ 20 km s^-1 for an extent of ~ 700 pc, beyond the size of the the H II region. Although the H I clouds are not easily separated in velocity with some mixed component represented by merged line profiles, the atomic gas mass amounts to 6 x 10^6 M_Sol and 9 x 10^6 M_Sol for each component. These characteristics of H I gas and the distributions of dense molecular gas in the overlapping regions of the two velocity components suggest that the formation of giant molecular clouds and the following massive cluster formation have been induced by the collision of H I clouds with different velocities. Referring to the existence of gas bridging feature connecting M33 with M31 reported by large-scale HI surveys, the disturbed atomic gas possibly represent the result of past tidal interaction between the two galaxies, which is analogous to the formation of the R136 cluster in the LMC., Comment: 10 pages, 11 figures, Accepted for publication in the Publications of the Astronomical Society of Japan
Published: 2018

35. Methyl isocyanate CH3NCO: An important missing organic in current astrochemical networks

Author: Pierre Gratier, Liton Majumdar, Audrey Coutens, Jean-Christophe Loison, M. Ruaud, Valentine Wakelam, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), NASA Ames Research Center Cooperative for Research in Earth Science in Technology (ARC-CREST), and NASA Ames Research Center (ARC)
Subjects: Astrochemistry, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Quantum chemical computations, Comet, FOS: Physical sciences, 02 engineering and technology, Astrophysics, Methyl isocyanate, 01 natural sciences, Organic molecules, Methods statistical, chemistry.chemical_compound, Phase (matter), 0103 physical sciences, Protostar, 010303 astronomy & astrophysics, Physics, Astronomy and Astrophysics, 021001 nanoscience & nanotechnology, Astrophysics - Astrophysics of Galaxies, 3. Good health, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0210 nano-technology
Abstract: Methyl isocyanate (CH3NCO) is one of the important complex organic molecules detected on the comet 67P/Churyumov-Gerasimenko by Rosetta's Philae lander. It was also detected in hot cores around high-mass protostars along with a recent detection in the solar-type protostar IRAS 16293-2422. We propose here a gas-grain chemical model to form CH3NCO after reviewing various formation pathways with quantum chemical computations. We have used NAUTILUS 3-phase gas-grain chemical model to compare observed abundances in the IRAS 16293-2422. Our chemical model clearly indicates the ice phase origin of CH3NCO., Accepted for publication in MNRAS Letters
Published: 2018

36. Experimental evidence for rock layering development by pressure solution

Author: François Renard, Jean-Pierre Gratier, and Catherine Noiriel
Subjects: Gypsum, Mass transfer, engineering, Mineralogy, Geology, Pressure solution, engineering.material, Layering, Microstructure, Dissolution, Volcanic ash, Diagenesis
Abstract: Natural deformation of rocks is commonly associated with development of mineralogical layering, leading to irreversible transformations of their microstructure. The mechanisms of such chemical differentiation processes during diagenesis, tectonics, metamorphism, or fault differentiation remain poorly understood, as they are difficult to reproduce experimentally due to the very slow kinetics involved. This paper shows that development of differentiated layering, similar to that observed in natural deformation, is stress driven and can be obtained from indenter experiments. Samples of (1) gypsum plaster mixed with clay, and (2) natural diatomite loosely interbedded with volcanic ash, saturated with aqueous solutions in equilibrium, were subjected to loading for several months at 40 °C and 150 °C, respectively. X-ray microtomography and scanning electron microscopy observations show that layering develops by a self-organized pressure solution process. Stress-driven dissolution of the soluble minerals (either gypsum or silica) is initiated in the areas initially richer in insoluble species (clay or volcanic ash), as diffusive mass transfer along the interface between soluble and insoluble minerals is much faster than along the healed boundaries of the soluble minerals. The passive concentration of the insoluble minerals amplifies the dissolution along layers oriented perpendicularly to the maximum compressive stress. Conversely, in areas with an initial low content of insoluble minerals and clustered soluble minerals, dissolution is slower. Consequently, these areas are less deformed; they host the re-deposition of the soluble species and act as rigid objects that concentrate both stress and dissolution near their boundaries, thus amplifying the differentiation and the development of layered microstructures.
Published: 2015

37. The interstellar chemistry of C

Author: Jean-Christophe, Loison, Marcelino, Agúndez, Valentine, Wakelam, Evelyne, Roueff, Pierre, Gratier, Núria, Marcelino, Dianailys, Nuñez Reyes, José, Cernicharo, and Maryvonne, Gerin
Subjects: Article
Abstract: We report the detection of linear and cyclic isomers of C3H and C3H2 towards various starless cores and review the corresponding chemical pathways involving neutral (C3Hx with x=1,2) and ionic (C3Hx+ with x = 1,2,3) isomers. We highlight the role of the branching ratio of electronic Dissociative Recombination (DR) reactions of C3H2+ and C3H3+ isomers showing that the statistical treatment of the relaxation of C3H* and C3H2* produced in these DR reactions may explain the relative c,l-C3H and c,l-C3H2 abundances. We have also introduced in the model the third isomer of C3H2 (HCCCH). The observed cyclic-to-linear C3H2 ratio vary from 110 ± 30 for molecular clouds with a total density around 1×104 molecules.cm-3 to 30 ± 10 for molecular clouds with a total density around 4×105 molecules.cm-3, a trend well reproduced with our updated model. The higher ratio for low molecular cloud densities is mainly determined by the importance of the H + l-C3H2 → H + c-C3H2 and H + t-C3H2 → H + c-C3H2 isomerization reactions.
Published: 2017

38. Clustering the Orion B giant molecular cloud based on its molecular emission

Author: Nicolas Peretto, Pierre Gratier, Javier R. Goicoechea, Karin I. Öberg, François Levrier, Sébastien Bardeau, Chloé Daudon, Harvey S. Liszt, Maryvonne Gerin, Emeric Bron, Jérôme Pety, Albrecht Sievers, Viviana V. Guzmán, Pascal Tremblin, Jan H. Orkisz, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), National Radio Astronomy Observatory (NRAO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], School of Physics and Astronomy [Cardiff], Cardiff University, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Grenoble Alpes (UGA), Harvard University-Smithsonian Institution, and European Project: 610256,EC:FP7:ERC,ERC-2013-SyG,NANOCOSMOS(2014)
Subjects: medicine.medical_specialty, ISM: individual objects: Orion B, Astrochemistry, ISM: structure, FOS: Physical sciences, Context (language use), 02 engineering and technology, Astrophysics, 01 natural sciences, ISM: clouds, Article, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, medicine, Radiative transfer, Cluster (physics), Cluster analysis, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, QB, Line (formation), Physics, methods: statistical, astrochemistry, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Spectral imaging, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 020201 artificial intelligence & image processing, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Previous attempts at segmenting molecular line maps of molecular clouds have focused on using position-position-velocity data cubes of a single line to separate the spatial components of the cloud. In contrast, wide field spectral imaging with large spectral bandwidth in the (sub)mm domain now allows to combine multiple molecular tracers to understand the different physical and chemical phases that constitute giant molecular clouds. We aim at using multiple tracers (sensitive to different physical processes) to segment a molecular cloud into physically/chemically similar regions (rather than spatially connected components). We use a machine learning clustering method (the Meanshift algorithm) to cluster pixels with similar molecular emission, ignoring spatial information. Simple radiative transfer models are used to interpret the astrophysical information uncovered by the clustering. A clustering analysis based only on the J=1-0 lines of 12CO, 13CO and C18O reveals distinct density/column density regimes (nH~100, 500, and >1000 cm-3), closely related to the usual definitions of diffuse, translucent and high-column-density regions. Adding two UV-sensitive tracers, the (1-0) lines of HCO+ and CN, allows us to distinguish two clearly distinct chemical regimes, characteristic of UV-illuminated and UV-shielded gas. The UV-illuminated regime shows overbright HCO+ and CN emission, which we relate to photochemical enrichment. We also find a tail of high CN/HCO+ intensity ratio in UV-illuminated regions. Finer distinctions in density classes (nH~7E3, and 4E4 cm-3) for the densest regions are also identified, likely related to the higher critical density of the CN and HCO+ (1-0) lines. The association of simultaneous multi-line, wide-field mapping and powerful machine learning methods such as the Meanshift algorithm reveals how to decode the complex information available in molecular tracers., Accepted for publication in A&A. 26 pages and 23 figures. The associated data products will soon be available at http://www.iram.fr/~pety/ORION-B
Published: 2017

39. Coseismic Damage Generation and Pulverization in Fault Zones

Author: Jean-Pierre Gratier, François Renard, Mai-Linh Doan, and Franciscus M. Aben
Subjects: 010504 meteorology & atmospheric sciences, business.industry, Geotechnical engineering, Split-Hopkinson pressure bar, Structural engineering, 010502 geochemistry & geophysics, business, 01 natural sciences, Geology, 0105 earth and related environmental sciences
Published: 2017

40. Geochemical transect through a travertine mount: A detailed record of CO 2 -enriched fluid leakage from Late Pleistocene to present-day – Little Grand Wash fault (Utah, USA)

Author: Dominique Blamart, Bruno Hamelin, Emanuelle Frery, Nadine Ellouz-Zimmerman, Jean-Pierre Gratier, Pierre Deschamps, Rudy Swennen, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF), IFP Energies nouvelles (IFPEN), Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Collège de France (CdF)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Institut National de la Recherche Agronomique (INRA), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Geology Section, Department of Earth and Environmental Sciences, K.U.Leuven (KU Leuven), Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Collège de France (CdF (institution))-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Paléocéanographie (PALEOCEAN), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Travertine, geography, Oxygen and carbon stable isotopes, geography.geographical_feature_category, Vein growth rate, 010504 meteorology & atmospheric sciences, Pleistocene, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Context (language use), Aquifer, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, CO2-enriched fluids, Paleontology, Meteoric water, Period (geology), Glacial period, Quaternary, Leakage, U/Th dating, [SDU.STU.AG]Sciences of the Universe [physics]/Earth Sciences/Applied geology, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: © 2016 Elsevier Ltd and INQUA Active and fossil endogenic travertine mounts scattered along the Little Grand Wash fault are studied as records of Quaternary CO2-enriched fluid leakage. This study focusses on a particular area where a fossil mount formed in a near-surface setting by successive circulation/sealing episodes from Late Pleistocene to Mid-Holocene and where a modern surface travertine is still being formed by a CO2-enriched fluid source. The fossil mount is composed of horizontal and vertical veins whereby the vertical veins recorded numerous cycles of circulation/sealing/dissolution events and were used as conduits for the CO2-enriched fluid circulation from the depth to the surface or along sub-horizontal fractures where successive precipitation events are recorded. The modern travertine is being built at the surface by successive eruption of Crystal Geyser, an anthropic geyser active since the 1930's. δ13C and δ18O signatures and U/Th datings, ranging from 11.5 ky till present-day allows calibrating in detail the CO2 enriched fluid leakage along a single fault segment and in a post glacial context, as last glaciations in the study area took place 15 ky ago. The dataset shows a high decrease of the oxygen stable isotope values till about 6 ky, then the variations reflect a constant range until present-day. This tends to restrain the period of local increase of the meteoric water input in the aquifer that is sourcing the CO2-enriched water. The fossil travertine represents a 7 ky-long record of CO2 leakage above a natural reservoir, from Late Pleistocene to Mid-Holocene. The flux of CO2 leakage through time and the total escaping volume have been computed and appears to be low in comparison with an anthropogenic leak provoked, for instance, by a non-sealed well. ispartof: Quaternary International vol:437 pages:98-106 status: published
Published: 2017

41. First records of syn-diagenetic non-tectonic folding in quaternary thermogene travertines caused by hydrothermal incremental veining

Author: Michele Soligo, Stefano M. Bernasconi, Andrea Billi, M Oruç Baykara, Sándor Kele, Luigi De Filippis, Gabriele Berardi, Gianluca Vignaroli, Jean-Pierre Gratier, Chuan-Chou Shen, Federico Rossetti, Billi, Andrea, Berardi, Gabriele, Gratier, Jean Pierre, Rossetti, Federico, Vignaroli, Gianluca, Oruç Baykara, M, Bernasconi, Stefano M, Kele, Sándor, Soligo, Michele, Filippis, Luigi De, Shen, Chuan Chou, Billi, A., Berardi, G., Gratier, J. P., Vignaroli, G., Oruc Baykara, M., Bernasconi, S., Kele, S., De Filippis, L., Shen, C. C., Gratier, Jean-Pierre, Baykara, M. Oruç, Bernasconi, Stefano M., De Filippis, Luigi, and Shen, Chuan-Chou
Subjects: folding, 010504 meteorology & atmospheric sciences, Geochronology, Geochemistry, Vein, Hydrothermal circulation, 010502 geochemistry & geophysics, 01 natural sciences, Sedimentary structures, Chronological sequences, Quaternary, Paleontology, Endocrinology, hydrothermal activity, travertine, Fold, buckling, Hydrothermalism, Paleoclimate oscillation, Sedimentology, Geophysic, 0105 earth and related environmental sciences, Earth-Surface Processes, Uranium alloys, Crystallization force, Crystal structure, Tectonics, deformation, Fold (geology), Binary alloys, Overprinting, Limestone, Thorium alloys, Diagenesis, Geophysics, Italy, vein (geology), Sedimentary rock, Deposits, Primary sedimentary structures, Vein (geology), Geology
Abstract: This study is the first documentation of syn-diagenetic non-tectonic contractional deformations observed in two Pleistocene thermogene travertine deposits from the late Miocene-Pleistocene Tuscan extensional-hydrothermal province (Italy). The deposits consist of primary porous beds hosting secondary bed-parallel carbonate veins. The porous beds are generally flat-lying, particularly in the upper section of the deposits, whereas the veined beds frequently form undulated structures. These structures are up to a few meters in wavelength, are mostly confined within the lower-middle section of the deposits, and are here mostly interpreted as folds. Field observations, U-Th geochronology, and stable isotope analyses are used to characterize the origin of veins and folds. Radiometrically-determined age inversions, structure overprinting relationships, downward growth of vein crystals, deformation of primary sedimentary structures, and downward increasing frequency of veins and folds show that the undulated travertine beds can be mainly interpreted as the product of syn-diagenetic hydrothermal rejuvenation causing non-tectonic veining and folding. The non-tectonic hypothesis is also supported by the absence of contractional deformation in the travertine-hosting sediments. The folds were generated by complex mechanisms including bending and buckling caused by laterally-confined volume expansion during syn-diagenetic circulation of mineralizing fluids and related incremental veining. Modeling some folds with the Biot-Ramberg's buckling equation shows a vein-to-host travertine viscosity ratio between 1.5 and 4, confirming the syn-diagenetic origin of folds. Veining and folding changed some original properties of travertines including rheology, fabric, porosity, and chronological sequence. The identification of these structures and related changes of rock properties (e.g., age rejuvenation) is relevant for the proper interpretation of thermogene travertines as recorders of many geological processes including paleoclimate oscillations, earthquake occurrences, hydrothermal circulations, and uplift or incision rates. Synthesizing, the studied thermogene travertines appear more like sedimentary-hydrothermal-hybrid zoned deposits rather than pure sedimentary systems uniquely responding to the superposition law. © 2017 Elsevier B.V.
Published: 2017

42. First detection of interstellar S2H

Author: E. Roueff, Jérôme Pety, Javier R. Goicoechea, Pablo Riviere-Marichalar, Thomas H. G. Vidal, Valentine Wakelam, Romane Le Gal, Guillermo M. Muñoz Caro, Maryvonne Gerin, Viviana V. Guzmán, Rafael Martín-Doménech, Asunción Fuente, Pierre Gratier, Jean-Christophe Loison, Observatorio Astronomico Nacional, Madrid, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), National Radio Astronomy Observatory (NRAO)-European Southern Observatory (ESO), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), European Research Council, Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Institut national des sciences de l'Univers (France), École normale supérieure - Paris (ENS-PSL), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: Astrochemistry, Abundance (chemistry), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Analytical chemistry, FOS: Physical sciences, 01 natural sciences, ISM: abundances, Ion, Desorption, 0103 physical sciences, Molecule, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), molecules [ISM], abundances [ISM], Physics, Nebula, 010304 chemical physics, ISM: individual objects (Horsehead), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Methods: laboratory: solid state, Photon-dominated region (PDR), Interstellar medium, laboratory: solid state [Methods], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Yield (chemistry), individual objects (Horsehead) [ISM]
Abstract: We present the first detection of gas-phase SH in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed SH abundance is ∼5 × 10, only a factor of 4-6 lower than that of the widespread HS molecule. HS and SH are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the HS and SH photodesorption yields. The obtained values are ∼1.2 × 10 and, V.W.'s research is funded by an ERC Starting Grant (3DICE, grant agreement 336474). We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, AYA2012-32032 and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. This work was supported by the Programme National >Physique et Chimie du Milieu Interstellaire> (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.
Published: 2017

43. Dissecting the molecular structure of the Orion B cloud: Insight from Principal Component Analysis

Author: Nicolas Peretto, Emeric Bron, Franck Le Petit, Karin I. Öberg, Evelyne Roueff, Viviana V. Guzmán, Pascal Tremblin, Sébastien Bardeau, Albrech Sievers, Javier R. Goicoechea, Jérôme Pety, Jan H. Orkisz, Maryvonne Gerin, Harvey S. Liszt, Pierre Gratier, AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Université Grenoble Alpes (UGA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Instituto de RadioAstronomía Milimétrica (IRAM), University of Exeter, Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), European Research Council, Institut national des sciences de l'Univers (France), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Smithsonian Institution-Harvard University [Cambridge], Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS-PSL), Harvard University-Smithsonian Institution, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Brightness, ISM: individual objects: Orion B, statistical [Methods], Astrochemistry, Field (physics), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, ISM: clouds, Spectral line, photon-dominated region (PDR), 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, QB, Physics, methods: statistical, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Interstellar medium, individual objects: Orion B [ISM], Photon-dominated region (PDR), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Principal component analysis, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: [Context] The combination of wideband receivers and spectrometers currently available in (sub-)millimeter observatories deliver wide-field hyperspectral imaging of the interstellar medium. Tens of spectral lines can be observed over degree wide fields in about 50 h. This wealth of data calls for restating the physical questions about the interstellar medium in statistical terms., [Aims] We aim to gain information on the physical structure of the interstellar medium from a statistical analysis of many lines from different species over a large field of view, without requiring detailed radiative transfer or astrochemical modeling., [Methods] We coupled a non-linear rescaling of the data with one of the simplest multivariate analysis methods, namely the principal component analysis, to decompose the observed signal into components that we interpret first qualitatively and then quantitatively based on our deep knowledge of the observed region and of the astrochemistry at play., [Results] We identify three principal components, linear compositions of line brightness temperatures, that are correlated at various levels with the column density, the volume density and the UV radiation field., [Conclusions] When sampling a sufficiently diverse mixture of physical parameters, it is possible to decompose the molecular emission in order to gain physical insight on the observed interstellar medium. This opens a new avenue for future studies of the interstellar medium., This work was supported by the French program Physique et Chimie du Milieu Interstellaire (PCMI) funded by the Conseil National de la Recherche Scientifique (CNRS) and Centre National d’Études Spatiales (CNES). P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. P.G.’s current postdoctoral position is funded by the INSU/CNRS.
Published: 2017

44. Turbulence and star formation efficiency in molecular clouds: solenoidal versus compressive motions in Orion B

Author: Javier R. Goicoechea, Nicolas Peretto, Maryvonne Gerin, Karin I. Öberg, Sébastien Bardeau, Viviana V. Guzmán, Pascal Tremblin, Evelyne Roueff, Harvey S. Liszt, Franck Le Petit, Pierre Gratier, François Levrier, Albrecht Sievers, Jan H. Orkisz, Jérôme Pety, Emeric Bron, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), University of Exeter, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Grenoble Alpes (UGA), Harvard University [Cambridge]-Smithsonian Institution, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS Paris), Smithsonian Institution-Harvard University [Cambridge], Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Science Foundation (US), Gobierno de Chile, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), European Research Council, and Institut national des sciences de l'Univers (France)
Subjects: ISM: individual objects: Orion B, statistical [Methods], [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astrophysics, ISM: clouds, 01 natural sciences, Momentum, symbols.namesake, 0103 physical sciences, Supersonic speed, 010306 general physics, 010303 astronomy & astrophysics, Methods: statistical, Radio lines: ISM, Equipartition theorem, Astrophysics::Galaxy Astrophysics, QB, ISM: kinematics and dynamics, Physics, Solenoidal vector field, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Turbulence, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM [Radio lines], individual objects: Orion B [ISM], kinematics and dynamics [ISM], Mach number, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), symbols, clouds [ISM]
Abstract: [Context] The nature of turbulence in molecular clouds is one of the key parameters that control star formation efficiency: compressive motions, as opposed to solenoidal motions, can trigger the collapse of cores, or mark the expansion of Hii regions., [Aims] We try to observationally derive the fractions of momentum density (ρv) contained in the solenoidal and compressive modes of turbulence in the Orion B molecular cloud and relate these fractions to the star formation efficiency in the cloud., [Methods] The implementation of a statistical method applied to a CO(J = 1-0) datacube obtained with the IRAM-30 m telescope, enables us to retrieve 3-dimensional quantities from the projected quantities provided by the observations, which yields an estimate of the compressive versus solenoidal ratio in various regions of the cloud., [Results] Despite the Orion B molecular cloud being highly supersonic (mean Mach number ~ 6), the fractions of motion in each mode diverge significantly from equipartition. The cloud's motions are, on average, mostly solenoidal (excess > 8% with respect to equipartition), which is consistent with its low star formation rate. On the other hand, the motions around the main star forming regions (NGC 2023 and NGC 2024) prove to be strongly compressive., [Conclusions] We have successfully applied to observational data a method that has so far only been tested on simulations, and we have shown that there can be a strong intra-cloud variability of the compressive and solenoidal fractions, these fractions being in turn related to the star formation efficiency. This opens a new possibility for star formation diagnostics in galactic molecular clouds., This work was supported by the CNRS/CNES program Physique et Chimie du Milieu Interstellaire (PCMI). V.V.G. thanks for support from the Chilean Government through the Becas Chile program. P.G.’s postdoctoral position was funded by the INSU/CNRS. P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. NRAO is operated by Associated Universities Inc. under contract with the National Science Foundation.
Published: 2017

45. High strain rate deformation of porous sandstone and the asymmetry of earthquake damage in shallow fault zones

Author: Mai-Linh Doan, François Renard, Jean-Pierre Gratier, F. M. Aben, Institut des Sciences de la Terre (ISTerre), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de recherche pour le développement [IRD] : UR219-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), European Project: 316889,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,FLOWTRANS(2013), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2)
Subjects: 010504 meteorology & atmospheric sciences, Bedding, Lithology, sandstone compaction bands, Compaction, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, earthquake rupture mechanisms, Fault (geology), 010502 geochemistry & geophysics, 01 natural sciences, rock pulverization, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Geotechnical engineering, Petrology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, fault zone damage, Strain rate, high strain rate experiments, Overburden pressure, Geophysics, Space and Planetary Science, coseismic damage, Sedimentary rock, Deformation (engineering), Geology
Abstract: In contrast to coseismic pulverization of crystalline rocks, observations of coseismic pulverization in porous sedimentary rocks in fault damage zones are scarce. Also, juxtaposition of stiff crystalline rocks and compliant porous rocks across a fault often yields an asymmetric damage zone geometry, with less damage in the more compliant side. In this study, we argue that such asymmetry near the sub-surface may occur because of a different response of lithology to similar transient loading conditions. Uniaxial unconfined high strain rate loadings with a split Hopkinson pressure bar were performed on dry and water saturated Rothbach sandstone core samples. Bedding anisotropy was taken into account by coring the samples parallel and perpendicular to the bedding. The results show that pervasive pulverization below the grain scale, such as observed in crystalline rock, does not occur in the sandstone samples for the explored strain rate range (60–150 s−1). Damage is mainly restricted to the scale of the grains, with intragranular deformation occurring only in weaker regions where compaction bands are formed. The presence of water and the bedding anisotropy mitigates the formation of compaction bands and motivates intergranular dilatation. The competition between inter- and intragranular damage during dynamic loading is explained with the geometric parameters of the rock in combination with two classic micromechanical models: the Hertzian contact model and the pore-emanated crack model. In conclusion, the observed microstructures can form in both quasi-static and dynamic loading regimes. Therefore caution is advised when interpreting the mechanism responsible for near-fault damage in sedimentary rock near the surface. Moreover, the results suggest that different responses of lithology to transient loading are responsible for sub-surface damage zone asymmetry.
Published: 2017

46. Microstructures Induced in Porous Limestone by Dynamic Loading, and Fracture Healing: An Experimental Approach

Author: Julie Richard, Mai-Linh Doan, François Renard, and Jean-Pierre Gratier
Subjects: geography, Materials science, geography.geographical_feature_category, Nucleation, Compaction, Split-Hopkinson pressure bar, Strain rate, Fault (geology), Permeability (earth sciences), Geophysics, Geochemistry and Petrology, Dynamic loading, Geotechnical engineering, Pressure solution
Abstract: Fracturing and healing are crucial processes inducing changes in the permeability and mechanical behavior of fault zones. Fracturing increases the permeability of fault rocks, creating flow-channels for fluid circulation and enhancing the kinetics of such fluid–rock processes as pressure solution or metamorphism. Conversely, healing processes reduce permeability by closing the fractures and lead to rock strengthening. Consequently, the timescales of these two processes are important in determining the strength of fault zones and their ability to rupture during earthquakes. This article reports observations of the microstructure of porous limestone samples subjected to rapid dynamic loading, and long-term healing as a result of fluid percolation. Dynamic loading was performed by impacting the samples with steel bars inside a split Hopkinson pressure bar apparatus. Healing was performed by leaving the samples for three months within a triaxial machine with percolation of supersaturated fluids for five weeks. Two kinds of fracture network were observed in samples damaged at high strain rate: a series of radial and circular macrofractures and an incipient pulverization zone at the center of the sample loaded at the highest strain rate. Fracture density determined microscopically from X-ray images correlates with dissipated energy computed from macro-mechanical data. X-ray images enable good quantification of the damaged state of the samples. Percolation experiments under stress with high-solubility fluid at room temperature show that the main healing processes promoting closure of the fractures in the sample are a combination of mechanical and chemical compaction. Microfracturing networks were found to heal faster than the largest fractures, leading to heterogeneous strengthening of the rock. This feature affects the processes of earthquake nucleation and rupture propagation.
Published: 2014

47. Rock and mineral transformations in a fault zone leading to permanent creep: Interactions between brittle and viscous mechanisms in the San Andreas Fault

Author: Mai-Linh Doan, François Renard, Julie Richard, Jean-Pierre Gratier, and Anne-Marie Boullier
Subjects: Metamorphic rock, Active fault, San Andreas Fault Observatory at Depth, Geophysics, Brittleness, Creep, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Cleavage (geology), Geotechnical engineering, Pressure solution, Shear zone, Petrology, Geology
Abstract: Creep processes may relax part of the tectonic stresses in active faults, either by continuous or episodic processes. The aim of this study is to obtain a better understanding of these creep mechanisms and the manner in which they change in time and space. Results are presented from microstructural studies of natural samples collected from San Andreas Fault Observatory at Depth borehole drilled through the San Andreas Fault, which reveal the chronology of the deformation within three domain types. (i) A relatively undeformed zone of the host rock reflects the first step of the deformation process with fracturing and grain indentations showing the coupling between fracturing and pressure solution. (ii) Shear deformation development that associates fracturing and solution cleavage processes leads to profound changes in rock composition and behavior with two types of development depending on the ratio between the amount of dissolution and deposition: abundant mineral precipitation strengthens some zones while pervasive dissolution weakens some others, (iii) zones with mainly dissolution trended toward the present-day creeping zones thanks to both the passive concentration of phyllosilicates and their metamorphic transformation into soft minerals such as saponite. This study shows how interactions between brittle and viscous mechanisms lead to widespread transformation of the rocks and how a shear zone may evolve from a zone prone to earthquakes and postseismic creep to a zone of steady state creep. In parallel, the authors discuss how the creeping mechanism, mainly controlled by the very low friction of the saponite in the first 3–4 km depth, may evolve with depth.
Published: 2014

48. Postseismic pressure solution creep: Evidence and time‐dependent change from dynamic indenting experiments

Author: François Renard, Jean-Pierre Gratier, and Benjamin Vial
Subjects: geography, geography.geographical_feature_category, Aseismic creep, Fault (geology), Power law, Geophysics, Creep, Space and Planetary Science, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Geotechnical engineering, Comminution, Pressure solution, Contact area, Displacement (fluid), Geology
Abstract: Active faults in the Earth's upper crust can slide either steadily by aseismic creep or abruptly causing earthquakes. Seismic and aseismic processes are closely related: earthquakes are often followed by transient afterslip creep. Postseismic displacement rates progressively decrease with time over a period of years or decades. So seismic fracturing activates the creep rate, and various healing processes progressively reduce it. This article presents pressure solution indenter experiments on halite, calcite, and plaster that show how fracturing and comminution processes induced by dynamic stress loading (applied by dropping steel balls) drastically accelerate the displacement rates accommodated by pressure solution creep by decreasing the dissolution contact area and the diffusive mass transfer distance along this contact. However, as fractures progressively heal and dissolution contacts flatten, these effects disappear, and the displacement rates slow down. The time-dependent change in indenter displacement after dynamic stress loading has been measured and is best fitted by power laws with exponents that change with time from 0.3 to 1 when healing is achieved. Natural postseismic (afterslip) displacement/time relationships have been analyzed and also show a power law change with a power law exponent in the range of 0.25–0.4. It is proposed that the variation in power law exponent with time is related to the change in morphology of the dissolution contact that is fractured or comminuted during the dynamic event and is then progressively healed and smoothed. In natural faults, monitoring the power law parameters could give access to the characteristic healing time in the fault.
Published: 2014

49. Geological control of the partitioning between seismic and aseismic sliding behaviours in active faults: Evidence from the Western Alps, France

Author: A. Tourette, François Renard, François Thouvenot, Mai-Linh Doan, L. Jenatton, and Jean-Pierre Gratier
Subjects: geography, geography.geographical_feature_category, Subduction, Aseismic creep, Active fault, Fault (geology), Tectonics, Geophysics, Creep, Earthquake rupture, Pressure solution, Geology, Seismology, Earth-Surface Processes
Abstract: Given that active faults can slide either continuously by aseismic creep or episodically during earthquakes, and that the same fault zone may evolve laterally from seismic to aseismic deformation, an important issue is to know whether seismic to aseismic transition can be geologically controlled. This article presents examples of contrasted mechanical behaviour along active faults that cross cut limestone and marl units within the sedimentary cover of the French Alps. By matching seismic events along strike-slip and normal faults with the nature and structure of the rocks, it is demonstrated that the partition between seismic and aseismic sliding at depth is geologically controlled: earthquakes nucleate in the strongest rocks, mainly limestones, whereas marls accommodate at least part of the tectonic loading by aseismic creep. By looking at exhumed rocks deformed in the same context it is possible to identify the mechanism of creep, which is shown to be pressure solution creep either as a permanent or post-seismic creep. As earthquakes slip are seen to propagate through the whole upper crust, creep processes do not necessarily prevent an earthquake rupture from propagating through creeping units. However, creep relaxes stress and consequently reduces the available elastic potential energy at the origin of earthquakes in such creeping zones. The key parameters of pressure solution creep laws are presented and discussed. Using these laws, it is possible to infer why marl may creep more easily than limestone or why highly fractured limestone may creep more easily than intact rock. This approach also identifies other rocks that could creep by pressure solution in subduction zones and indicates how creeping zones may act as barriers for earthquake rupture propagation. Finally, the criteria possibly revealing geological control of the transition between seismic and aseismic sliding at depth are discussed with respect to subduction zones.
Published: 2013

50. Inferring asymmetric limb cloudiness on exoplanets from transit light curves

Author: Franck Selsis, Pascal Borde, Jérémy Leconte, P. von Paris, Pierre Gratier, ECLIPSE 2016, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and AMOR 2016
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, 010504 meteorology & atmospheric sciences, business.industry, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Cloud cover, FOS: Physical sciences, Astronomy and Astrophysics, Cloud computing, Astrophysics, Phase curve, Ephemeris, Light curve, 01 natural sciences, Exoplanet, Stars, Space and Planetary Science, Planet, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, business, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences
Abstract: Clouds have been shown to be present in many exoplanetary atmospheres. Cloud formation modeling predicts considerable inhomogeneities of cloud cover, consistent with optical phase curve observations. However, optical phase curves cannot resolve some existing degeneracies between cloud location and cloud optical properties. We present a conceptually simple technique to detect inhomogeneous cloud cover on exoplanets. Such an inhomogeneous cloud cover produces an asymmetric primary transit of the planet in front of the host star. Asymmetric transits produce characteristic residuals compared to a standard symmetric model. Furthermore, bisector spans can be used to determine asymmetries in the transit light curve. We apply a model of asymmetric transits to the light curves of HAT-P-7b, Kepler-7b and HD209458b and search for possible cloud signatures. The nearly uninterrupted Kepler photometry is particularly well-suited for this method since it allows for a very high time resolution. We do not find any statistically sound cloud signature in the data of the considered planets. For HAT-P-7b, a tentative detection of an asymmetric cloud cover is found, consistent with analysis of the optical phase curve. Based on Bayesian probability arguments, a symmetric model with an offset in the transit ephemeris remains, however, the most viable model. Still, this work demonstrates that for suitable targets, namely low-gravity planets around bright stars, the method can be used to constrain cloud cover characteristics and is thus a helpful additional tool to study exoplanetary atmospheres., accepted for publication in Astronomy&Astrophysics on Feb. 12th, 11 pages, 20 figures, 2 tables, + Appendix
Published: 2016

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Publication Type

Journal

Database

Publisher

176 results on '"Pierre Gratier"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources