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122 results on '"Zavagno, Annie"'

1. Compact and High Excitation Molecular Clumps in the Extended Ultraviolet Disk of M83

Author: Koda, Jin, Combes, Francoise, Rubio, Monica, Andersen, Morten, Bigiel, Frank, de Paz, Armando Gil, Junais, Lee, Amanda M, Meyer, Jennifer Donovan, Morokuma-Matsui, Kana, Yagi, Masafumi, and Zavagno, Annie
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The extended ultraviolet (XUV) disks of nearby galaxies show ongoing massive star formation, but their parental molecular clouds remain mostly undetected despite searches in CO(1-0) and CO(2-1). The recent detection of 23 clouds in the higher excitation transition CO(3-2) within the XUV disk of M83 requires an explanation. We test the hypothesis: the clouds in XUV disks have a clump-envelope structure similar to those in Galactic star-forming clouds, having star-forming dense clumps (or concentrations of multiple clumps) at their centers, which predominantly contribute to the CO(3-2) emission, surrounded by less-dense envelopes, where CO molecules are photo-dissociated due to the low-metallicity environment there. We utilize new high-resolution ALMA CO(3-2) observations of a subset (11) of the 23 clouds in the XUV disk. We confirm the compactness of the CO(3-2)-emitting dense clumps (or their concentrations), finding clump diameters below the spatial resolution of 6-9~pc. This is similar to the size of the dense gas region in the Orion A molecular cloud, the local star-forming cloud with massive star formation. The dense star-forming clumps are common between normal and XUV disks. This may also indicate that once the cloud structure is set, the process of star formation is governed by the cloud internal physics rather than by external triggers. This simple model explains the current observations of the clouds with ongoing massive star formation, although it may require some adjustment, e.g., including an effect of cloud evolution, for a general scenario of star formation in molecular clouds., Comment: A&A accepted; 15 pages, 8 figures - after proof
Published: 2024

2. From Bubbles and Filaments to Cores and Disks: Gas Gathering and Growth of Structure Leading to the Formation of Stellar Systems

Author: Pineda, Jaime E., Arzoumanian, Doris, André, Philippe, Friesen, Rachel K., Zavagno, Annie, Clarke, Seamus D., Inoue, Tsuyoshi, Chen, Che-Yu, Lee, Yueh-Ning, Soler, Juan D., and Kuffmeier, Michael
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: The study of the development of structures on multiple scales in the cold interstellar medium has experienced rapid expansion in the past decade, on both the observational and the theoretical front. Spectral line studies at (sub-)millimeter wavelengths over a wide range of physical scales have provided unique probes of the kinematics of dense gas in star-forming regions, and have been complemented by extensive, high dynamic range dust continuum surveys of the column density structure of molecular cloud complexes, while dust polarization maps have highlighted the role of magnetic fields. This has been accompanied by increasingly sophisticated numerical simulations including new physics (e.g., supernova driving, cosmic rays, non-ideal magneto-hydrodynamics, radiation pressure) and new techniques such as zoom-in simulations allowing multi-scale studies. Taken together, these new data have emphasized the anisotropic growth of dense structures on all scales, from giant ISM bubbles driven by stellar feedback on $\sim$50-100 pc scales through parsec-scale molecular filaments down to $<$0.1 pc dense cores and $<$1000 au protostellar disks. Combining observations and theory, we present a coherent picture for the formation and evolution of these structures and synthesize a comprehensive physical scenario for the initial conditions and early stages of star and disk formation., Comment: 42 pages, 20 figures. To appear in Protostars and Planets VII, Editors: Shu-ichiro Inutsuka, Yuri Aikawa, Takayuki Muto, Kengo Tomida, and Motohide Tamura. Small changes to match proofs and the updated format
Published: 2022

3. Velocity structure of the 50 pc-long NGC 6334 filamentary cloud: Hints of multiple compressions and their impact on the cloud properties?

Author: Arzoumanian, Doris, Russeil, Delphine, Zavagno, Annie, Chen, Michael Chun-Yuan, André, Philippe, Inutsuka, Shu-ichiro, Misugi, Yoshiaki, Sánchez-Monge, Álvaro, Schilke, Peter, Men'shchikov, Alexander, and Kohno, Mikito
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Solar and Stellar Astrophysics
Abstract: [Abridged] The interstellar medium is observed to be organised in filamentary structures, as well as neutral (HI) and ionized (HII) bubbles. The expanding nature of these bubbles makes them shape their surroundings and possibly play a role in the formation and evolution of interstellar filaments. We present APEX $^{13}$CO and C$^{18}$O(2-1) observations of the NGC 6334 molecular cloud. We investigate the gas velocity structure along and across the 50 pc-long cloud and towards 75 identified velocity-coherent-filaments (VCFs). We measure a wealth of velocity gradients along the VCFs. We derive the column density and velocity power spectra of the VCFs. These power spectra are well represented with power laws showing similar slopes for both quantities (with a mean of about -2), albeit some differ by up to a factor of two. The position velocity diagrams perpendicular to three VCFs show the V-shaped velocity pattern, corresponding to a bent structure in velocity space with the filament at the tip of the V surrounded by an extended structure connected to it with a velocity gradient. This velocity structure is qualitatively similar to that resulting from numerical simulations of filament formation from large-scale compression from propagating shock fronts. In addition, the radial profiles perpendicular to these VCFs hint to small-scale internal impacts from neighbouring HII bubbles. The observed opposite curvature in velocity space towards the VCFs points to various origins of large-scale external compressions from propagating HI bubbles. This suggests the plausible importance of multiple HI compressions, separated in space and time, in the formation and evolution of molecular clouds and their star formation history. These latter atomic compressions due to past and distant star formation events are complemented by the impact of HII bubbles from present time and local star formation activity., Comment: Accepted for publication in Astronomy & Astrophysics
Published: 2022
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4. Stellar feedback and triggered star formation in the prototypical bubble RCW 120

Author: Luisi, Matteo, Anderson, Loren D., Schneider, Nicola, Simon, Robert, Kabanovic, Slawa, Güsten, Rolf, Zavagno, Annie, Broos, Patrick S., Buchbender, Christof, Guevara, Cristian, Jacobs, Karl, Justen, Matthias, Klein, Bernd, Linville, Dylan, Röllig, Markus, Russeil, Delphine, Stutzki, Jürgen, Tiwari, Maitraiyee, Townsley, Leisa K., and Tielens, Alexander G. G. M.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Radiative and mechanical feedback of massive stars regulates star formation and galaxy evolution. Positive feedback triggers the creation of new stars by collecting dense shells of gas, while negative feedback disrupts star formation by shredding molecular clouds. Although key to understanding star formation, their relative importance is unknown. Here, we report velocity-resolved observations from the SOFIA (Stratospheric Observatory for Infrared Astronomy) legacy program FEEDBACK of the massive star-forming region RCW 120 in the [CII] 1.9-THz fine-structure line, revealing a gas shell expanding at 15 km/s. Complementary APEX (Atacama Pathfinder Experiment) CO J=3-2 345-GHz observations exhibit a ring structure of molecular gas, fragmented into clumps that are actively forming stars. Our observations demonstrate that triggered star formation can occur on much shorter time scales than hitherto thought (<0.15 million years), suggesting that positive feedback operates on short time periods., Comment: 8 Pages, 4 Figures, 1 Table (+16 Page Supplementary Materials with 10 Figures). Published in Science Advances on April 9th, 2021, with free open access to the online article available at https://advances.sciencemag.org/content/7/15/eabe9511
Published: 2021
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5. APEX CO observations towards the photodissociation region of RCW120

Author: Figueira, Miguel, Zavagno, Annie, Bronfman, Leonardo, Russeil, Delphine, Finger, Ricardo, and Schuller, Frédéric
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The edges of ionized (HII) regions are important sites for the formation of (high-mass) stars. Indeed, at least 30% of the galactic high mass star formation is observed there. The radiative and compressive impact of the HII region could induce the star formation at the border following different mechanisms such as the Collect & Collapse (C&C) or the Radiation Driven Implosion (RDI) models and change their properties. We study the properties of two zones located in the Photo Dissociation Region (PDR) of the Galactic HII region RCW120 and discussed them as a function of the physical conditions and young star contents found in both clumps. Using the APEX telescope, we mapped two regions of size 1.5'$\times$1.5' toward the most massive clump of RCW120 hosting young massive sources and toward a clump showing a protrusion inside the HII region and hosting more evolved low-mass sources. The $^{12}$CO($J=3-2$), $^{13}$CO($J=3-2$) and C$^{18}$O($J=3-2$) lines are used to derive the properties and dynamics of these clumps. We discuss their relation with the hosted star-formation. The increase of velocity dispersion and $T_{ex}$ are found toward the center of the maps, where star-formation is observed with Herschel. Furthermore, both regions show supersonic Mach number. No strong evidences have been found concerning the impact of far ultraviolet (FUV) radiation on C$^{18}$O photodissociation. The fragmentation time needed for the C&C to be at work is equivalent to the dynamical age of RCW120 and the properties of region B are in agreement with bright-rimmed clouds. It strengthens the fact that, together with evidences of compression, C&C might be at work at the edges of RCW120. Additionally, the clump located at the eastern part of the PDR is a good candidate of pre-existing clump where star-formation may be induced by the RDI mechanism., Comment: 13 pages, 12 Figures To be published in A&A
Published: 2020
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6. Unveiling the importance of magnetic fields in the evolution of dense clumps formed at the waist of bipolar H II regions: a case study on Sh2-201 with JCMT SCUBA-2/POL-2

Author: Eswaraiah, Chakali, Li, Di, Samal, Manash R., Wang, Jia-Wei, Ma, Yuehui, Lai, Shih-Ping, Zavagno, Annie, Ching, Tao-Chung, Liu, Tie, Pattle, Kate, Ward-Thompson, Derek, Pandey, Anil K., and Ojha, Devendra K.
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the properties of magnetic fields (B-fields) in two clumps (clump 1 and clump 2), located at the waist of the bipolar H II region Sh2-201, based on JCMT SCUBA-2/POL-2 observations of 850 $\mu$m polarized dust emission. We find that B-fields in the direction of the clumps are bent and compressed, showing bow-like morphologies, which we attribute to the feedback effect of the H II region on the surface of the clumps. Using the modified Davis-Chandrasekhar-Fermi method we estimate B-fields strengths of 266 $\mu$G and 65 $\mu$G for clump 1 and clump 2, respectively. From virial analyses and critical mass ratio estimates, we argue that clump 1 is gravitationally bound and could be undergoing collapse, whereas clump 2 is unbound and stable. We hypothesize that the interplay between thermal pressure imparted by the H II region, B-field morphologies, and the various internal pressures of the clumps (such as magnetic, turbulent, and gas thermal pressure), has the following consequences: (a) formation of clumps at the waist of the H II region; (b) progressive compression and enhancement of the B-fields in the clumps; (c) stronger B-fields will shield the clumps from erosion by the H II region and cause pressure equilibrium between the clumps and the H II region, thereby allowing expanding I-fronts to blow away from the filament ridge, forming bipolar H II regions; and (d) stronger B-fields and turbulence will be able to stabilize the clumps. A study of a larger sample of bipolar H II regions would help to determine whether our hypotheses are widely applicable., Comment: 25 pages, 10 figures, and 4 tables. Accepted for publication in ApJ
Published: 2019
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7. The effects of ionization feedback on star formation: A case study of the M16 H II region

Author: Xu, Jin-Long, Zavagno, Annie, Yu, Naiping, Liu, Xiao-Lan, Xu, Ye, Yuan, Jinghua, Zhang, Chuan-Peng, Zhang, Si-Ju, Zhang, Guo-Yin, Ning, Chang-Chun, and Ju, Bing-Gang
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract: We aim to investigate the impact of the ionized radiation from the M16 HII region on the surrounding molecular cloud and on its hosted star formation. To present comprehensive multi-wavelength observations towards the M16 HII region, we used new CO data and existing infrared, optical, and submillimeter data. The 12CO J=1-0, 13CO J=1-0, and C18O J=1-0 data were obtained with the Purple Mountain Observatory (PMO) 13.7m radio telescope. To trace massive clumps and extract young stellar objects (YSOs) associated with the M16 HII region, we used the ATLASGAL and GLIMPSE I catalogs, respectively. From CO data, we discern a large-scale filament with three velocity components. Because these three components overlap with each other in both velocity and space, the filament may be made of three layers. The M16 ionized gas interacts with the large-scale filament and has reshaped its structure. In the large-scale filament, we find 51 compact cores from the ATLASGAL catalog, 20 of them being quiescent. The mean excitation temperature of these cores is 22.5 K, while this is 22.2 K for the quiescent cores. This high temperature observed for the quiescent cores suggests that the cores may be heated by M16 and do not experience internal heating from sources in the cores. Through the relationship between the mass and radius of these cores, we obtain that 45% of all the cores are massive enough to potentially form massive stars. Compared with the thermal motion, the turbulence created by the nonthermal motion is responsible for the core formation. For the pillars observed towards M16, the H II region may give rise to the strong turbulence., Comment: 18 pages, 12 figures, accepted for publication in A&A
Published: 2019
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8. Bipolar H{\sc ii} regions produced by cloud/cloud collisions

Author: Whitworth, Anthony, Lomax, Oliver, Balfour, Scott, Mège, Pierre, Zavagno, Annie, and Deharveng, Lise
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We suggest that Bipolar H{\sc ii} Regions may be the aftermath of collisions between clouds. Such a collision will produce a shock-compressed layer, and a star cluster can then condense out of the dense gas near the centre of the layer. If the clouds are sufficiently massive, the star cluster is likely to contain at least one massive star, which emits ionising radiation, and excites an H{\sc ii} region, which then expands, sweeping up the surrounding neutral gas. Once most of the matter in the clouds has accreted onto the layer, expansion of the H{\sc ii} Region meets little resistance in directions perpendicular to the mid-plane of the layer, and so it expands rapidly to produce two lobes of ionised gas, one on each side of the layer. Conversely, in directions parallel to the mid-plane of the layer, expansion of the H{\sc ii} Region stalls due to the ram-pressure of the gas that continues to fall towards the star cluster from the outer parts of the layer; a ring of dense neutral gas builds up around the waist of the Bipolar H{\sc ii} Region, and may spawn a second generation of star formation. In this paper we present a dimensionless model for the flow of ionised gas in a Bipolar H{\sc ii} Region created according to the above scenario, and predict the characteristics of the resulting freefree continuum and recombination-line emission. This dimensionless model can be scaled to the physical parameters of any particular system. Our intention is that these predictions will be useful in testing the scenario outlined above, and thereby providing indirect support for the role of cloud/cloud collisions in triggering star formation., Comment: 17 pages, 6 figures
Published: 2018
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9. ALMA observations of RCW 120 Fragmentation at 0.01pc scale

Author: Figueira, Miguel, Bronfman, Leonardo, Zavagno, Annie, Louvet, Fabien, Lo, Nadia, Finger, Ricardo, and Rodón, Javier
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: Little is known about how high-mass stars form. Around 30\% of the young high-mass stars in the Galaxy are observed at the edges of ionized (HII) regions. Therefore these are places of choice to study the earliest stages of high-mass star formation, especially towards the most massive condensations. High-spatial resolution observations in the millimeter range might reveal how these stars form and how they assemble their mass. We want to study the fragmentation process down to the 0.01~pc scale in the most massive condensation observed at the south-western edge of the HII region RCW~120 where the most massive Herschel cores ($\sim$124~$M_{\odot}$ in average) could form high-mass stars. Using ALMA 3~mm continuum observations towards the densest and most massive millimetric condensation (Condensation 1) of RCW~120, we used the getimages and getsources algorithms to extract the sources detected with ALMA and obtained their physical parameters. The fragmentation of the hersche cores is discussed through their Jeans mass to understand the properties of the future stars. We extracted 18 fragments from the ALMA continuum observation at 3~mm towards 8 cores detected with Herschel, whose mass and deconvolved size range from 2~$M_{\odot}$ to 32~$M_{\odot}$ and from 1.6~mpc to 28.8~mpc, respectively. The low degree of fragmentation observed, regarding to the thermal Jeans fragmentation, suggests that the observed fragmentation is inconsistent with ideal gravitational fragmentation and other ingredients such as turbulence or magnetic fields should be added in order to explain it. Finally, the range of fragments' mass indicates that the densest condensation of RCW~120 is a favourable place for the formation of high-mass stars with the presence of a probable UCHII region associated with the 27~$M_{\odot}$ Fragment 1 of Core 2., Comment: 7 pages, 4 figures
Published: 2018
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10. High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22

Author: Yuan, Jinghua, Li, Jin-Zeng, Wu, Yuefang, Ellingsen, Simon P., Henkel, Christian, Wang, Ke, Liu, Tie, Liu, Hong-Li, Zavagno, Annie, Ren, Zhiyuan, and Huang, Ya-Fang
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: How mass is accumulated from cloud-scale down to individual stars is a key open question in understanding high-mass star formation. Here, we present the mass accumulation process in a hub-filament cloud G22 which is composed of four supercritical filaments. Velocity gradients detected along three filaments indicate that they are collapsing with a total mass infall rate of about 440 $M_\odot$ Myr$^{-1}$, suggesting the hub mass would be doubled in six free-fall times, adding up to $ \sim2 $ Myr. A fraction of the masses in the central clumps C1 and C2 can be accounted for through large-scale filamentary collapse. Ubiquitous blue profiles in HCO$^+$ $ (3-2) $ and $^{13}$CO $ (3-2) $ spectra suggest a clump-scale collapse scenario in the most massive and densest clump C1. The estimated infall velocity and mass infall rate are 0.31 km s$^{-1}$ and $ 7.2 \times10^{-4} $ $M_\odot$ yr$^{-1}$, respectively. In clump C1, a hot molecular core (SMA1) is revealed by the SMA observations and an outflow-driving high-mass protostar is located at the center of SMA1. The mass of the protostar is estimated to be $ 11-15 $ $M_\odot$ and it is still growing with an accretion rate of $ 7\times10^{-5} $ $M_\odot$ yr$^{-1}$. The coexistent infall in filaments, clump C1, and the central hot core in G22 suggests that pre-assembled mass reservoirs (i.e., high-mass starless cores) may not be required to form high-mass stars. In the course of high-mass star formation, the central protostar, the core, and the clump can simultaneously grow in mass via core-fed/disk accretion, clump-fed accretion, and filamentary/cloud collapse., Comment: 17 pages, 16 figures 3 tables. and Accepted for publication in ApJ
Published: 2017
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11. High-mass Starless Clumps in the inner Galactic Plane: the Sample and Dust Properties

Author: Yuan, Jinghua, Wu, Yuefang, Ellingsen, Simon P., Evans II, Neal J., Henkel, Christian, Wang, Ke, Liu, Hong-Li, Liu, Tie, Li, Jin-Zeng, and Zavagno, Annie
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: We report a sample of 463 high-mass starless clump (HMSC) candidates within $-60\deg0.08$ g cm$^{-2}$ could be possible high-mass starless cores. Further investigations toward these HMSCs would undoubtedly shed light on comprehensively understanding the birth of high-mass stars., Comment: 16 pages, 15 figures, and 5 tables. Accepted for publication in ApJS. FITS images for the far-IR to sub-mm data, H2 column density and dust temperature maps of all the HMSC candidates are available at https: //yuanjinghua.github.io/hmscs.html. Codes used for this work are publicly available from https://github.com/yuanjinghua/HMSCs_cat
Published: 2017
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12. Herschel observations of the Galactic HII region RCW 79

Author: Liu, Hong-Li, Figueira, Miguel, Zavagno, Annie, Hill, Tracey, Schneider, Nicola, Men'shchikov, Alexander, Russeil, Delphine, Motte, Frederique, Tige, Jeremy, Deharveng, Lise, Anderson, L. D., Li, Jin-Zeng, Wu, Yuefang, Yuan, Jing-Hua, and Huang, Maohai
Subjects: Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract: Triggered star formation around HII regions could be an important process. The Galactic HII region RCW 79 is a prototypical object for triggered high-mass star formation. We take advantage of Herschel data from the surveys HOBYS, "Evolution of Interstellar Dust", and Hi-Gal to extract compact sources in this region, complemented with archival 2MASS, Spitzer, and WISE data to determine the physical parameters of the sources (e.g., envelope mass, dust temperature, and luminosity) by fitting the spectral energy distribution. We obtained a sample of 50 compact sources, 96% of which are situated in the ionization-compressed layer of cold and dense gas that is characterized by the column density PDF with a double-peaked lognormal distribution. The 50 sources have sizes of 0.1-0.4 pc with a typical value of 0.2 pc, temperatures of 11-26 K, envelope masses of 6-760 $M_\odot$, densities of 0.1-44 $\times$ $10^5$ cm$^{-3}$, and luminosities of 19-12712 $L_\odot$. The sources are classified into 16 class 0, 19 intermediate, and 15 class I objects. Their distribution follows the evolutionary tracks in the diagram of bolometric luminosity versus envelope mass (Lbol-Menv) well. A mass threshold of 140 $M_\odot$, determined from the Lbol-Menv diagram, yields 12 candidate massive dense cores that may form high-mass stars. The core formation efficiency (CFE) for the 8 massive condensations shows an increasing trend of the CFE with density. This suggests that the denser the condensation, the higher the fraction of its mass transformation into dense cores, as previously observed in other high-mass star-forming regions., Comment: Accepted by A&A on 17 January 2017
Published: 2017
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13. Interactions of the Infrared bubble N4 with the surroundings

Author: Liu, Hong-Li, Li, Jin-Zeng, Wu, Yuefang, Yuan, Jing-Hua, Liu, Tie, Dubner, G., Paron, S., Ortega, M. E., Molinari, Sergio, Huang, Maohai, Zavagno, Annie, Samal, Manash R., Huang, Ya-Fang, and Zhang, Si-Ju
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The physical mechanisms that induce the transformation of a certain mass of gas in new stars are far from being well understood. Infrared bubbles associated with HII regions have been considered to be good samples of investigating triggered star formation. In this paper we report on the investigation of the dust properties of the infrared bubble N4 around the HII region G11.898+0.747, analyzing its interaction with its surroundings and star formation histories therein, with the aim of determining the possibility of star formation triggered by the expansion of the bubble. Using Herschel PACS and SPIRE images with a wide wavelength coverage, we reveal the dust properties over the entire bubble. Meanwhile, we are able to identify six dust clumps surrounding the bubble, with a mean size of 0.50 pc, temperature of about 22 K, mean column density of 1.7 $\times10^{22}$ cm$^{-2}$, mean volume density of about 4.4 $\times10^{4}$ cm$^{-3}$, and a mean mass of 320 $M_{\odot}$. In addition, from PAH emission seen at 8 $\mu$m, free-free emission detected at 20 cm and a probability density function in special regions, we could identify clear signatures of the influence of the HII region on the surroundings. There are hints of star formation, though further investigation is required to demonstrate that N4 is the triggering source., Comment: Accepted by ApJ (16 pages, 11 figures, 9 tables)
Published: 2016
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14. The Milky Way as a Star Formation Engine

Author: Molinari, Sergio, Bally, John, Glover, Simon, Moore, Toby, Noriega-Crespo, Alberto, Plume, René, Testi, Leonardo, Vázquez-Semadeni, Enrique, Zavagno, Annie, Bernard, Jean-Philippe, and Martin, Peter
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: The cycling of material from the interstellar medium (ISM) into stars and the return of stellar ejecta into the ISM is the engine that drives the "galactic ecology" in normal spirals, a cornerstone in the formation and evolution of galaxies through cosmic time. Major observational and theoretical challenges need to be addressed in determining the processes responsible for converting the low-density ISM into dense molecular clouds, forming dense filaments and clumps, fragmenting them into stars, OB associations and bound clusters, and characterizing the feedback that limits the rate and efficiency of star formation. This formidable task can be now effectively attacked thanks to the combination of new global-scale surveys of the Milky Way Galactic Plane from infrared to radio wavelengths, offering the possibility of bridging the gap between local and extragalactic star formation studies. The Herschel, Spitzer and WISE mid to far infrared continuum surveys, complemented by analogue surveys from ground-based facilities in the millimetre and radio wavelengths, enables us to measure the Galactic distribution and physical properties of dust on all scales and in all components of the ISM from diffuse clouds to filamentary complexes and tens of thousands of dense clumps. A complementary suite of spectroscopic surveys in various atomic and molecular tracers is providing the chemical fingerprinting of dense clumps and filaments, as well as essential kinematic information to derive distances and thus transform panoramic data into a 3D representation. The latest results emerging from these Galaxy-scale surveys are reviewed. New insights into cloud formation and evolution, filaments and their relationship to channeling gas onto gravitationally-bound clumps, the properties of these clumps, density thresholds for gravitational collapse, and star and cluster formation rates are discussed., Comment: Accepted for publication as a chapter in Protostars and Planets VI, University of Arizona Press (2014), eds. H. Beuther, R. Klessen, C. Dullemond, Th. Henning (minor text revisions, plus updated figure 11)
Published: 2014
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15. Dissecting Star-forming regions with the GeMS MCAO instrument: lessons learned for optimal post-processing of WFAO data

Author: Bernard, Ana¨ıs, Neichel, Benoit, Fusco, Thierry, Mugnier, Laurent, Bounissou, Sophie, Samal, Manash, Andersen, Morten, Zavagno, Annie, and Plana, Henri
Subjects: Wide field adaptive optics, data processing, star forming region, photometry, correction of distortions
Abstract: The advent of a new generation of Wide Field AO (WFAO) systems marks the beginning of a new era in high spatial resolution imaging. By using multiple Laser Guide Stars, WFAO significantly increases the field of view of the AOcorrected images, and the fraction of the sky that can benefit from such correction. The newly commissioned Gemini South Multi-Conjugate Adaptive Optics System (GeMS) combined with the infrared camera GSAOI is delivering almost di raction-limited images over a field of 2 arc-minutes across. In this paper, we first present recent observations of the young star-forming region N159W located in the Large Magellanic Cloud. We obtained deep JHKs images from the GeMS/ GSAOI instrument and developed reduction tools, in order to photometrically study the properties of the stellar members of the cluster and to bring new elements to our understanding of the process of massive star formation. However, despite the excellent performance of the GeMS/ GSAOI system, some variable residues are still limiting the correction quality over the field. In particular, GSAOI is severely a ected by distortion that can strongly degrade the resolution when combining multiple frames and can consequently reduce the sensitivity. The accuracy of the distortion correction of an instrument is critical for its use for high- precision astrometry and photometry. In a second part of this paper, we investigate an optimal way to correct for the distortion following an inverse problem approach. The formalism as well as first simulation results are presented.
Published: 2015

16. Variation in dust properties in a dense filament of the Taurus molecular complex (L1506)

Author: Ysard, Nathalie, Abergel, Alain, Ristorcelli, Isabelle, Juvela, Mika, Pagani, Laurent, Konyves, Vera, Spencer, Locke, White, Glenn, and Zavagno, Annie
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We observed the L1506 filament, which is located in the Taurus molecular complex, with the Herschel PACS and SPIRE instruments. Our aim is to prove the variation in grain properties along the entire length of the filament. In particular, we want to determine above which gas density this variation arises and what changes in the grain optical properties/size distribution are required. We use the 3D radiative transfer code CRT, coupled to the dust emission and extinction code DustEM, to model the emission and extinction of the dense filament. We test a range of optical properties and size distributions for the grains: dust of the diffuse interstellar medium (interstellar PAHs and amorphous carbons and silicates) and both compact and fluffy aggregates. We find that the grain opacity has to increase across the filament to fit simultaneously the near-IR extinction and Herschel emission profiles of L1506. We interpret this change to be a consequence of the coagulation of dust grains to form fluffy aggregates. Grains similar to those in the diffuse medium have to be present in the outer layers of the cloud, whereas aggregates must prevail above gas densities of a few 1000 H/cm3. This corresponds to line-of-sights with visual extinction in the V band of the order of 2 to 3. The dust opacity at 250 microns is raised by a factor of 1.8 to 2.2, while the grain average size is increased by a factor of 5. These exact numbers depend naturally on the dust model chosen to fit the data. Our findings agree with the constraints given by the study of the gas molecular lines. Using a simple approach, we show that the aggregates may have time to form inside the filament within the cloud lifetime. Our model also characterises the density structure of the filament, showing that the filament width is not constant along L1506 but instead varies by a factor of the order of 4., Comment: accepted for publication in A&A, low resolution figures to match the requirements of arXiv
Published: 2013
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17. Filaments and ridges in Vela C revealed by Herschel: from low-mass to high-mass star-forming sites

Author: Hill, Tracey, Motte, Frederique, Didelon, Pierre, Bontemps, Sylvain, Minier, Vincent, Hennemann, Martin, Schneider, Nicola, Andre, Philippe, Men'shchikov, Alexander, Anderson, Loren D., Arzoumanian, Doris, Bernard, Jean-Philippe, di Francesco, James, Elia, Davide, Giannini, Teresa, Griffin, Matt J., Kirk, Jason, Konyves, Vera, Marston, Anthony P., Martin, Peter, Molinari, Sergio, Luong, Quang Nguyen, Peretto, Nicolas, Pezzuto, Stefano, Roussel, Helene, Sauvage, Marc, Sousbie, Thierry, Testi, Leonardo, Ward-Thompson, Derek, White, Glenn J., Wilson, Christine D., and Zavagno, Annie
Subjects: Astrophysics - Astrophysics of Galaxies
Abstract: We present the first Herschel PACS and SPIRE results of the Vela C molecular complex in the far-infrared and submillimetre regimes at 70, 160, 250, 350, and 500 um, spanning the peak of emission of cold prestellar or protostellar cores. Column density and multi-resolution analysis (MRA) differentiates the Vela C complex into five distinct sub-regions. Each sub-region displays differences in their column density and temperature probability distribution functions (PDFs), in particular, the PDFs of the `Centre-Ridge' and `South-Nest' sub-regions appear in stark contrast to each other. The Centre-Ridge displays a bimodal temperature PDF representative of hot gas surrounding the HII region RCW 36 and the cold neighbouring filaments, whilst the South-Nest is dominated by cold filamentary structure. The column density PDF of the Centre-Ridge is flatter than the South-Nest, with a high column density tail, consistent with formation through large-scale flows, and regulation by self-gravity. At small to intermediate scales MRA indicates the Centre-Ridge to be twice as concentrated as the South-Nest, whilst on larger scales, a greater portion of the gas in the South-Nest is dominated by turbulence than in the Centre-Ridge. In Vela C, high-mass stars appear to be preferentially forming in ridges, i.e., dominant high column density filaments., Comment: 7 pages + 2 page figure appendix, 8 Figures (one in the appendix). Accepted by A&A
Published: 2011
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18. Calibration of the AKARI Far-Infrared Imaging Fourier Transform Spectrometer

Author: Murakami, Noriko, Kawada, Mitsunobu, Takahashi, Hidenori, Okada, Yoko, Yasuda, Akiko, Ootsubo, Takafumi, Kaneda, Hidehiro, Matsuo, Hiroshi, Baluteau, Jean-Paul, Davis-Imhof, Peter, Gom, Brad G., Naylor, David A., Zavagno, Annie, Yamamura, Issei, Matsuura, Shuji, Shirahata, Mai, Doi, Yasuo, Nakagawa, Takao, and Shibai, Hiroshi
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: The Far-Infrared Surveyor (FIS) onboard the AKARI satellite has a spectroscopic capability provided by a Fourier transform spectrometer (FIS-FTS). FIS-FTS is the first space-borne imaging FTS dedicated to far-infrared astronomical observations. We describe the calibration process of the FIS-FTS and discuss its accuracy and reliability. The calibration is based on the observational data of bright astronomical sources as well as two instrumental sources. We have compared the FIS-FTS spectra with the spectra obtained from the Long Wavelength Spectrometer (LWS) of the Infrared Space Observatory (ISO) having a similar spectral coverage. The present calibration method accurately reproduces the spectra of several solar system objects having a reliable spectral model. Under this condition the relative uncertainty of the calibration of the continuum is estimated to be $\pm$ 15% for SW, $\pm$ 10% for 70-85 cm^(-1) of LW, and $\pm$ 20% for 60-70 cm^(-1) of LW; and the absolute uncertainty is estimated to be +35/-55% for SW, +35/-55% for 70-85 cm^(-1) of LW, and +40/-60% for 60-70 cm^(-1) of LW. These values are confirmed by comparison with theoretical models and previous observations by the ISO/LWS., Comment: 22 pages, 10 figures
Published: 2010
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19. Triggered star formation on the borders of the Galactic HII region RCW 120

Author: Zavagno, Annie, Pomares, Melanie, Deharveng, Lise, Hosokawa, Takashi, Russeil, Delphine, and Caplan, James
Subjects: Astrophysics
Abstract: To investigate the process of star formation triggered by the expansion of an HII region, we present a multi-wavelength analysis of the Galactic HII region RCW 120 and its surroundings. The collect and collapse model predicts that the layer of gas and dust accumulated between the ionization and shock fronts during the expansion of the HII region collapses and forms dense fragments, giving rise to potential sites of massive-star formation. The aim of our study is to look for such massive fragments and massive young stars on the borders of RCW 120. We mapped the RCW 120 region in the cold dust continuum emission at 1.2 mm to search for these fragments. We supplemented this study with the available near- (2MASS) and mid-IR (GLIMPSE) data to locate the IR sources observed towards this region and to analyse their properties. We then compared the observational results with the predictions of Hosokawa & Inutsuka's model (2005, 2006). At 1.2 mm we detected eight fragments towards this region, five located on its borders. The largest fragment has a mass of about 370 Msun. Class I and Class II young stellar objects are detected all over the region, with some observed far from the ionization front. This result emphasises the possible importance distant interactions between the radiation, escaping from the ionized region, and the surrounding medium.
Published: 2007
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20. Stellar Feedback in the Star Formation-Gas Density Relation: Comparison between Simulations and Observations

Author: Suin, Paolo, Zavagno, Annie, Colman, Tine, Hennebelle, Patrick, Verliat, Antoine, Russeil, Delphine, Suin, Paolo, Zavagno, Annie, Colman, Tine, Hennebelle, Patrick, Verliat, Antoine, and Russeil, Delphine
Abstract: Context. The impact of stellar feedback on the Kennicutt-Schmidt law (KS law), which relates star formation rate (SFR) to surface gas density, is a topic of ongoing debate. The interpretation of individual cloud observations is challenging due to the various processes at play simultaneously and inherent biases. Therefore, a numerical investigation is necessary to understand the role of stellar feedback and identify observable signatures. Aims. We investigate the role of stellar feedback on the KS law, aiming to identify distinct signatures that can be observed and analysed. Methods. We analyse MHD numerical simulations of a $10^4\,M_{\odot}$ cloud evolving under different feedback prescriptions. The set of simulations contains four types of feedback: with only protostellar jets, with ionising radiation from massive stars $(>8\,M_{\odot})$, with both of them and without any stellar feedback. To compare these simulations with the existing observational results, we analyse their evolution by adopting the same techniques applied in observational studies. Then, we simulate how the same analyses would change if the data were affected by typical observational biases. Conclusions. The presence of stellar feedback strongly influences the KS relation and the star formation efficiency per free-fall time ($\epsilon_\mathrm{ff}$). Its impact is primarily governed by its influence on the cloud's structure. Although the $\epsilon_\mathrm{ff}$ measured in our clouds results to be higher than what is usually observed in real clouds, upon applying prescriptions to mimic observational biases we recover good agreement with the expected values. Therefore, we can infer that observations tend to underestimate the total SFR. Moreover, this likely indicates that the physics included in our simulations is sufficient to reproduce the basic mechanisms contributing to set $\epsilon_\mathrm{ff}$., Comment: 16 pages, 13 figures, accepted for publication to A&A
Published: 2023

21. ATOMS: ALMA three-millimeter observations of massive star-forming regions – XIII. Ongoing triggered star formation within clump-fed scenario found in the massive (∼1500 M⨀) clump

Author: Zhang, Siju, primary, Wang, Ke, additional, Liu, Tie, additional, Zavagno, Annie, additional, Juvela, Mika, additional, Liu, Hongli, additional, Tej, Anandmayee, additional, Stutz, Amelia M, additional, Li, Shanghuo, additional, Bronfman, Leonardo, additional, Zhang, Qizhou, additional, Goldsmith, Paul F, additional, Lee, Chang Won, additional, Vázquez-Semadeni, Enrique, additional, Tatematsu, Ken’ichi, additional, Jiao, Wenyu, additional, Xu, Fengwei, additional, Wang, Chao, additional, and Zhou, Jian-Wen, additional
Published: 2023
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22. Segmentation of the Galactic ISM Filaments using Deep Learning and Hi-GAL Catalogue

Author: BENSAID Siouar, ZAVAGNO Annie, and DUPÉ François Xavier
Subjects: ISM, filaments segmentation, Hi-GAL catalogue, AI, UNet, Deep Learning, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Understanding star formation is key to understand galaxy evolution. Observations collected in the Herschel Infrared Galactic plane Survey (Hi-GAL) revealed the ubiquitous presence of filamentary structures in the Galactic Plane. Filaments host star formation. Therefore, it is very interesting to study them and analyze the environment effect on their life cycle. A first step in understanding filaments consists in detecting them in the Galactic Plane. Detection algorithms based on standard image processing techniques present several limitations. Taking into consideration the drastic progress in Artificial Intelligence (AI), along with the data abundance about filaments, we propose to explore filament segmentation using Deep Learning (DL) framework. In this paper, we use state-of-the-art image segmentation in DL, U-Net, to segment filaments in all the Galactic Plane, in H2 column density images of the Galactic Plane obtained with Herschel Hi-GAL data. The used ground truth consists in the Hi-GAL filament catalogue provided by Schisano et al. Obtained results reveal more structures than provided in the catalogue, which makes AI-based methods very promising for such application.
Published: 2022
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23. ATOMS: ALMA three-millimeter observations of massive star-forming regions – XIII. Ongoing triggered star formation within clump-fed scenario found in the massive (∼1500 M⨀) clump.

Author: Zhang, Siju, Wang, Ke, Liu, Tie, Zavagno, Annie, Juvela, Mika, Liu, Hongli, Tej, Anandmayee, Stutz, Amelia M, Li, Shanghuo, Bronfman, Leonardo, Zhang, Qizhou, Goldsmith, Paul F, Lee, Chang Won, Vázquez-Semadeni, Enrique, Tatematsu, Ken'ichi, Jiao, Wenyu, Xu, Fengwei, Wang, Chao, and Zhou, Jian-Wen
Subjects: STAR formation, SUPERGIANT stars, IONIZED gases, IONIZING radiation, GAS flow, PROTOSTARS
Abstract: Whether ionization feedback triggers the formation of massive stars is highly debated. Using ALMA 3-mm observations with a spatial resolution of ∼0.05 pc and a mass sensitivity of 1.1 |$\rm M_\odot$| per beam at 20 K, we investigate the star formation and gas flow structures within the ionizing feedback-driven structure, a clump-scale massive (≳ 1500 |$\rm M_\odot$|⁠) bright-rimmed cloud (BRC) associated with IRAS 18290–0924. This BRC is bound only if external compression from ionized gas is considered. A small-scale (≲ 1 pc) age sequence along the direction of ionizing radiation is revealed for the embedded cores and protostars, which suggests triggered star formation via radiation-driven implosion (RDI). Furthermore, filamentary gas structures converge towards the cores located in the BRC's centre, indicating that these filaments are fueling mass towards cores. The local core-scale mass infall rate derived from H13CO+ J = 1 − 0 blue profile is of the same order of magnitude as the filamentary mass inflow rate, approximately 1 |$\rm M_\odot$| kyr−1. A photodissociation region (PDR) covering the irradiated clump surface is detected in several molecules, such as CCH, HCO+, and CS whereas the spatial distribution stratification of these molecules is indistinct. CCH spectra of the PDR possibly indicate a photoevaporation flow leaving the clump surface with a projected velocity of ∼2 km s−1. Our new observations show that RDI accompanied by a clump-fed process is operating in this massive BRC. Whether this combined process works in other massive BRCs is worth exploring with dedicated surveys. [ABSTRACT FROM AUTHOR]
Published: 2023
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24. Velocity structure of the 50 pc long NGC 6334 filamentary cloud

Author: Arzoumanian, Doris, primary, Russeil, Delphine, additional, Zavagno, Annie, additional, Chun-Yuan Chen, Michael, additional, André, Philippe, additional, Inutsuka, Shu-ichiro, additional, Misugi, Yoshiaki, additional, Sánchez-Monge, Álvaro, additional, Schilke, Peter, additional, Men’shchikov, Alexander, additional, and Kohno, Mikito, additional
Published: 2022
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25. H II regions and high-mass starless clump candidates

Author: Zhang, S., Zavagno, Annie, López-Sepulcre, A., Liu, H., Louvet, F., Figueira, M., Russeil, D., Wu, Y., Yuan, J., Pillai, T. G. S., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), Centro de Matemática e Aplicações Fundamentais (CMAF), Universidade de Lisboa (ULISBOA), Franche-Comté Électronique Mécanique, Thermique et Optique - Sciences et Technologies (UMR 6174) (FEMTO-ST), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS), 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), Universidade de Lisboa = University of Lisbon (ULISBOA), Université de Technologie de Belfort-Montbeliard (UTBM)-Ecole Nationale Supérieure de Mécanique et des Microtechniques (ENSMM)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), and Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)
Subjects: stars: massive, HII regions, stars: formation, techniques: interferometric, ISM: structure, submillimeter: ISM, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context. The ionization feedback from H II regions modifies the properties of high-mass starless clumps (HMSCs, of several hundred to a few thousand solar masses with a typical size of 0.1–1 pc), such as dust temperature and turbulence, on the clump scale. The question of whether the presence of H II regions modifies the core-scale (~0.025 pc) fragmentation and star formation in HMSCs remains to be explored.Aims. We aim to investigate the difference of 0.025 pc-scale fragmentation between candidate HMSCs that are strongly impacted by H II regions and less disturbed ones. We also search for evidence of mass shaping and induced star formation in the impacted candidate HMSCs.Methods. Using the ALMA 1.3 mm continuum, with a typical angular resolution of 1.3′′, we imaged eight candidate HMSCs, including four impacted by H II regions and another four situated in the quiet environment. The less-impacted candidate HMSCs are selected on the basis of their similar mass and distance compared to the impacted ones to avoid any possible bias linked to these parameters. We carried out a comparison between the two types of candidate HMSCs. We used multi-wavelength data to analyze the interaction between H II regions and the impacted candidate HMSCs.Results. A total of 51 cores were detected in eight clumps, with three to nine cores for each clump. Within our limited sample, we did not find a clear difference in the ~0.025 pc-scale fragmentation between impacted and non-impacted candidate HMSCs, even though H II regions seem to affect the spatial distribution of the fragmented cores. Both types of candidate HMSCs present a thermal fragmentation with two-level hierarchical features at the clump thermal Jeans length λJ,clumpth and 0.3λJ,clumpth. The ALMA emission morphology of the impacted candidate HMSCs AGAL010.214-00.306 and AGAL018.931-00.029 sheds light on the capacities of H II regions to shape gas and dust in their surroundings and possibly to trigger star formation at ~0.025 pc-scale in candidate HMSCs.Conclusions. The fragmentation at ~0.025 pc scale for both types of candidate HMSCs is likely to be thermal-dominant, meanwhile H II regions probably have the capacity to assist in the formation of dense structures in the impacted candidate HMSCs. Future ALMA imaging surveys covering a large number of impacted candidate HMSCs with high turbulence levels are needed to confirm the trend of fragmentation indicated in this study.
Published: 2021

26. SPHERE+: Imaging young Jupiters down to the snowline

Author: Augereau, J. -C., Baudino, J. -L., Beuzit, J. -L., Bouret, J. -C., Desert, J. -M., Delisle, J. -B., Orazi, V. D, Gonzalez, J. -F., Lagrange, A. -M., Coroller, H. Le, Arena, G. Muro, Diaye, M. N, Sauvage, J. -F., Schmid, H. -M., Boccaletti, A., Chauvin, G., Mouillet, D., Absil, O., Allard, F., Antoniucci, S., Augereau, J.-C, Barge, P., Baruffolo, A., Baudino, J.-L, Baudoz, P., Beaulieu, M., Benisty, M., Beuzit, J.-L, Bianco, A., Biller, B., Bonavita, B., Bonnefoy, M., Bos, S., Bouret, J.-C, Brandner, W., Buchschache, N., Carry, B., Cantalloube, F., Cascone, E., Carlotti, A., Charnay, B., Chiavassa, A., Choquet, E., Clenet, Y., Crida, A., De Boer, J., De Caprio, V., Desidera, S., Desert, J.-M, Delisle, J.-B, Delorme, P., Dohlen, K., Doelman, D., Dominik, C., D'orazi, V, Dougados, C., Douté, S., Fedele, D., Feldt, M., Ferreira, F., Fontanive, C., Fusco, T., Galicher, R., Garufi, A., Gendron, E., Ghedina, A., Ginski, C., Gonzalez, J.-F, Gratadour, D., Gratton, R., Guillot, T., Haffert, S., Hagelberg, J., Henning, T., Huby, E., Janson, M., Kamp, I., Keller, C. U., Kenworthy, M., Kervella, P., Kral, Q., Kuhn, J., Lagadec, E., Laibe, G., Langlois, M., Lagrange, A.-M, Launhardt, R., Leboulleux, L., Le Coroller, H, Causi, G. Li, Loupias, M., Maire, A. L., Marleau, G., Martinache, F., Martinez, P., Mary, D., Mattioli, M., Mazoyer, J., Meheut, H., Ménard, F., Mesa, D., Meunier, N., Miguel, Y., Milli, J., Min, M., Molliere, P., Mordasini, C., Moretto, G., Mugnier, L., Muro Arena, G, Nardetto, N., N'Diaye, M, Nesvadba, N., Pedichini, F., Pinilla, P., Por, E., Potier, A., Quanz, S., Rameau, J., Roelfsema, R., Rouan, D., Rigliaco, E., Salasnich, B., Samland, M., Sauvage, J.-F, Schmid, H.-M, Segransan, D., Snellen, I., Snik, F., Soulez, F., Stadler, E., Stam, D., Tallon, M., Thebault, P., Thiebaut, E., Tschudi, C., Udry, S., van Holstein, R., Vernazza, P, Vidal, F., Vigan, A., Waters, R., Wildi, F., Willson, M., Zanutta, A., Zavagno, Annie, Zurlo, A., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Cte d’Azur, 96 Boulevard de l’Observatoire, Nice, 06300, France, Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Département de Recherche sur la Fusion Contrôlée (DRFC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), 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)-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, Department of Biochemistry and Molecular Biology, Mayo Clinic, Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), DOTA, ONERA, Université Paris Saclay [Châtillon], ONERA-Université Paris-Saclay, Université Côte d'Azur (UCA), University of Arizona, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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)-Université Paris Cité (UPCité), Institute of Astronomy [ETH Zürich], Department of Physics [ETH Zürich] (D-PHYS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), NOVA Optical Infrared Instrumentation Group, INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Observatoire Astronomique de l'Université de Genève (ObsGE), Université de Genève = University of Geneva (UNIGE), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), SRON Netherlands Institute for Space Research (SRON), Croissance et propriétés de systèmes hybrides en couches minces (INSP-E8), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Université de Liège, Unité de recherche d'Économie et Sociologie Rurales (ESR), Institut National de la Recherche Agronomique (INRA), INAF - Osservatorio Astronomico di Roma (OAR), Universität Greifswald - University of Greifswald, European Southern Observatory [Santiago] (ESO), Immunopathologie et chimie thérapeutique (ICT), Institut de biologie moléculaire et cellulaire (IBMC), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute for Astronomy [Edinburgh] (IfA), University of Edinburgh, INAF - Osservatorio Astronomico di Capodimonte (OAC), Hôpital Cochin [AP-HP], Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), DOTA, ONERA, Université Paris Saclay [Palaiseau], Department of Astronomy, Stockholm University, Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Sterrewacht Leiden, Astrophysique Relativiste Théories Expériences Métrologie Instrumentation Signaux (ARTEMIS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-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 Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), 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 Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Universiteit Leiden
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract: SPHERE (Beuzit et al,. 2019) has now been in operation at the VLT for more than 5 years, demonstrating a high level of performance. SPHERE has produced outstanding results using a variety of operating modes, primarily in the field of direct imaging of exoplanetary systems, focusing on exoplanets as point sources and circumstellar disks as extended objects. The achievements obtained thus far with SPHERE (~200 refereed publications) in different areas (exoplanets, disks, solar system, stellar physics...) have motivated a large consortium to propose an even more ambitious set of science cases, and its corresponding technical implementation in the form of an upgrade. The SPHERE+ project capitalizes on the expertise and lessons learned from SPHERE to push high contrast imaging performance to its limits on the VLT 8m-telescope. The scientific program of SPHERE+ described in this document will open a new and compelling scientific window for the upcoming decade in strong synergy with ground-based facilities (VLT/I, ELT, ALMA, and SKA) and space missions (Gaia, JWST, PLATO and WFIRST). While SPHERE has sampled the outer parts of planetary systems beyond a few tens of AU, SPHERE+ will dig into the inner regions around stars to reveal and characterize by mean of spectroscopy the giant planet population down to the snow line. Building on SPHERE's scientific heritage and resounding success, SPHERE+ will be a dedicated survey instrument which will strengthen the leadership of ESO and the European community in the very competitive field of direct imaging of exoplanetary systems. With enhanced capabilities, it will enable an even broader diversity of science cases including the study of the solar system, the birth and death of stars and the exploration of the inner regions of active galactic nuclei., White paper submitted to ESO on Feb. 20th, 2020
Published: 2020

27. Stellar feedback and triggered star formation in the prototypical bubble RCW 120

Author: Luisi, Matteo, primary, Anderson, Loren D., additional, Schneider, Nicola, additional, Simon, Robert, additional, Kabanovic, Slawa, additional, Güsten, Rolf, additional, Zavagno, Annie, additional, Broos, Patrick S., additional, Buchbender, Christof, additional, Guevara, Cristian, additional, Jacobs, Karl, additional, Justen, Matthias, additional, Klein, Bernd, additional, Linville, Dylan, additional, Röllig, Markus, additional, Russeil, Delphine, additional, Stutzki, Jürgen, additional, Tiwari, Maitraiyee, additional, Townsley, Leisa K., additional, and Tielens, Alexander G. G. M., additional
Published: 2021
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28. H II regions and high-mass starless clump candidates

Author: Zhang, S., Zavagno, Annie, Yuan, J., Liu, H., Figueira, M., Russeil, D., Schuller, F., Marsh, K. A., Wu, Y., College of Aerospace Science and Engineering, National University of Defense Technology [China], Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), School of Electrical Engineering and Telecommunications (UNSW), University of New South Wales [Sydney] (UNSW), College of Urban and Environmental Sciences [Beijing], Peking University [Beijing], Max-Planck-Institut für Radioastronomie (MPIFR), and Plant & Food Research
Subjects: stars: formation, submillimeter: ISM, H II regions, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context. The role of ionization feedback on high-mass (>8 M⊙) star formation is still highly debated. Questions remain concerning the presence of nearby H II regions changes the properties of early high-mass star formation and whether H II regions promote or inhibit the formation of high-mass stars.Aims. To characterize the role of H II regions on the formation of high-mass stars, we study the properties of a sample of candidates high-mass starless clumps (HMSCs), of which about 90% have masses larger than 100 M⊙. These high-mass objects probably represent the earliest stages of high-mass star formation; we search if (and how) their properties are modified by the presence of an H II region.Methods. We took advantage of the recently published catalog of HMSC candidates. By cross matching the HMSCs and H II regions, we classified HMSCs into three categories: (1) the HMSCs associated with H II regions both in the position in the projected plane of the sky and in velocity; (2) HMSCs associated in the plane of the sky, but not in velocity; and (3) HMSCs far away from any H II regions in the projected sky plane. We carried out comparisons between associated and nonassociated HMSCs based on statistical analyses of multiwavelength data from infrared to radio.Results. We show that there are systematic differences of the properties of HMSCs in different environments. Statistical analyses suggest that HMSCs associated with H II regions are warmer, more luminous, more centrally-peaked and turbulent. We also clearly show, for the first time, that the ratio of bolometric luminosity to envelope mass of HMSCs (L∕M) could not be a reliable evolutionary probe for early massive star formation due to the external heating effects of the H II regions.Conclusions. We show HMSCs associated with H II regions present statistically significant differences from HMSCs far away from H II regions, especially for dust temperature and L∕M. More centrally peaked and turbulent properties of HMSCs associated with H II regions may promote the formation of high-mass stars by limiting fragmentation. High-resolution interferometric surveys toward HMSCs are crucial to reveal how H II regions impact the star formation process inside HMSCs.
Published: 2020

29. The role of Galactic H II regions in the formation of filaments

Author: ZAVAGNO, Annie, ANDRÉ, Ph., SCHULLER, F., PERETTO, N., SHIMAJIRI, Y., ARZOUMANIAN, D., CSENGERI, T., FIGUEIRA, M., FULLER, G. A., KÖNYVES, V., MEN’SHCHIKOV, A., PALMEIRIM, P., ROUSSEL, H., RUSSEIL, D., SCHNEIDER, N., ZHANG, S., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), 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), Leibniz-Institut für Astrophysik Potsdam (AIP), School of Physics and Astronomy [Cardiff], Cardiff University, Kagoshima University, Instituto de Astrofísica e Ciências do Espaço (IASTRO), 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), Jodrell Bank Centre for Astrophysics (JBCA), University of Manchester [Manchester], Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University Hospital of Cologne [Cologne], Supports from the French national programs on stellar and ISM physics (PNPS and PCMI)., Funding from the European Union’s Horizon 2020 research and innovation programmeunder grant agreement No 730562 [RadioNet]., ANR-16-CE92-0035,GENESIS,GENeration et Evolution des Structures du milieu InterStellaire(2016), ANR-11-BS56-0010,STARFICH,Vers une vision unifiée de la formation stellaire dans les galaxies : Origine de la structure filamentaire du milieu interstellaire, des cœurs pré-stellaires et des amas protostellaires vus avec Herschel(2011), ANR-05-BLAN-0215,ARTEMIS,ARchitectures de bolomètres pour des TElescopes à grand champ de vue dans le domaine sub-MIllimétrique au Sol(2005), ANR-11-LABX-0013,FOCUS,Des détecteurs pour Observer l'Univers(2011), European Project: 291294,EC:FP7:ERC,ERC-2011-ADG_20110209,ORISTARS(2012), and 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)
Subjects: stars: formation, ISM: individual objects: RCW 120, submillimeter: ISM, H II regions, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This research has made use of data from the Herschel HOBYS project (http://hobys-herschel.cea.fr). HOBYS is a Herschel Key Project jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG3), scientists of the LAM laboratory in Marseille, and scientists of the Herschel Science Center (HSC).; International audience; Context. Massive stars and their associated ionized (H II) regions could play a key role in the formation and evolution of filaments that host star formation. However, the properties of filaments that interact with H II regions are still poorly known.Aims. To investigate the impact of H II regions on the formation of filaments, we imaged the Galactic H II region RCW 120 and its surroundings where active star formation takes place and where the role of ionization feedback on the star formation process has already been studied.Methods. We used the large-format bolometer camera ArTéMiS on the APEX telescope and combined the high-resolution ArTéMiS data at 350 and 450 μm with Herschel-SPIRE/HOBYS data at 350 and 500 μm to ensure good sensitivity to a broad range of spatial scales. This allowed us to study the dense gas distribution around RCW 120 with a resolution of 8′′ or 0.05 pc at a distance of 1.34 kpc.Results. Our study allows us to trace the median radial intensity profile of the dense shell of RCW 120. This profile is asymmetric, indicating a clear compression from the H II region on the inner part of the shell. The profile is observed to be similarly asymmetric on both lateral sides of the shell, indicating a homogeneous compression over the surface. On the contrary, the profile analysis of a radial filament associated with the shell, but located outside of it, reveals a symmetric profile, suggesting that the compression from the ionized region is limited to the dense shell. The mean intensity profile of the internal part of the shell is well fitted by a Plummer-like profile with a deconvolved Gaussian full width at half maximum of 0.09 pc, as observed for filaments in low-mass star-forming regions.Conclusions. Using ArTéMiS data combined with Herschel-SPIRE data, we found evidence for compression from the inner part of the RCW 120 ionized region on the surrounding dense shell. This compression is accompanied with a significant (factor 5) increase of the local column density. This study suggests that compression exerted by H II regions may play a key role in the formation of filaments and may further act on their hosted star formation. ArTéMiS data also suggest that RCW 120 might be a 3D ring, rather than a spherical structure.
Published: 2020

30. Unveiling the Importance of Magnetic Fields in the Evolution of Dense Clumps Formed at the Waist of Bipolar H ii Regions: A Case Study of Sh 2-201 with JCMT SCUBA-2/POL-2

Author: Eswaraiah, Chakali, Li, Di, Samal, Manash R., Wang, Jia-Wei, Ma, Yuehui, Lai, Shih-Ping, Zavagno, Annie, Ching, Tao-Chung, Liu, Tie, Pattle, Kate, Ward-Thompson, Derek, Pandey, Anil K., Ojha, Devendra K., Eswaraiah, Chakali, Li, Di, Samal, Manash R., Wang, Jia-Wei, Ma, Yuehui, Lai, Shih-Ping, Zavagno, Annie, Ching, Tao-Chung, Liu, Tie, Pattle, Kate, Ward-Thompson, Derek, Pandey, Anil K., and Ojha, Devendra K.
Abstract: We present the properties of magnetic fields (B fields) in two clumps (clump 1 and clump 2), located at the waist of the bipolar H ii region Sh 2-201, based on James Clerk Maxwell Telescope SCUBA-2/POL-2 observations of 850 μm polarized dust emission. We find that B fields in the direction of the clumps are bent and compressed, showing bow-like morphologies, which we attribute to the feedback effect of the H ii region on the surface of the clumps. Using the modified Davis–Chandrasekhar–Fermi method, we estimate B-field strengths of 266 and 65 μG for clump 1 and clump 2, respectively. From virial analyses and critical mass ratio estimates, we argue that clump 1 is gravitationally bound and could be undergoing collapse, whereas clump 2 is unbound and stable. We hypothesize that the interplay of the thermal pressure imparted by the H ii region, the B-field morphologies, and the various internal pressures of the clumps (such as magnetic, turbulent, and gas thermal pressures) has the following consequences: (a) formation of clumps at the waist of the H ii region; (b) progressive compression and enhancement of the B fields in the clumps; (c) stronger B fields that will shield the clumps from erosion by the H ii region and cause pressure equilibrium between the clumps and the H ii region, thereby allowing expanding ionization fronts to blow away from the filament ridge, forming bipolar H ii regions; and (d) stronger B fields and turbulence that will be able to stabilize the clumps. A study of a larger sample of bipolar H ii regions would help to determine whether our hypotheses are widely applicable.
Published: 2020

31. Chemistry of Protostellar Clumps in the High-mass, Star-forming Filamentary Infrared Dark Cloud G034.43+00.24

Author: Liu, Hong-Li, primary, Sanhueza, Patricio, additional, Liu, Tie, additional, Zavagno, Annie, additional, Tang, Xin-Di, additional, Wu, Yuefang, additional, and Zhang, Siju, additional
Published: 2020
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32. Unveiling the Importance of Magnetic Fields in the Evolution of Dense Clumps Formed at the Waist of Bipolar H ii Regions: A Case Study of Sh 2-201 with JCMT SCUBA-2/POL-2

Author: Eswaraiah, Chakali, primary, Li, Di, additional, Samal, Manash R., additional, Wang, Jia-Wei, additional, Ma, Yuehui, additional, Lai, Shih-Ping, additional, Zavagno, Annie, additional, Ching, Tao-Chung, additional, Liu, Tie, additional, Pattle, Kate, additional, Ward-Thompson, Derek, additional, Pandey, Anil K., additional, and Ojha, Devendra K., additional
Published: 2020
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33. FRAGMENTATION OF MASSIVE CORES TOWARD THE GALACTIC Hii REGION RCW 120 OBSERVED WITH ALMA

Author: Figueira, M., Zavagno, Annie, Bronfman, L., National Centre for Nuclear Research [Otwock], Narodowe Centrum Badań Jądrowych (NCBJ), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Departamento de Astronomia (DAS), Société Francaise d’Astronomie et d’Astrophysique (SF2A), P. Di Matteo, O. Creevey, A. Crida, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and Beaussier, Catherine
Subjects: [SDU] Sciences of the Universe [physics], high-mass star, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU]Sciences of the Universe [physics], fragmentation, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Hii region, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: International audience; Feedback from high-mass stars (stellar winds, radiation and photoionization pressure, supernova explosions) can strongly modify the surrounding cloud. As a result, the next generation of stars is affected and can present different physical properties. Using ALMA interferometric observations, we characterized the fragmentation occurring inside the massive cores previously detected with Herschel and being good candidates for high-mass star formation. Most of the fragments have a mass higher than predicted by the thermal Jeans mechanism, thus requiring external turbulence to explain it, and some of the fragments have a mass higher than 8 M which make them interesting targets for further studies. One of the fragment shows different molecular emissions tracing hot core, disk and outflows and is the most promising site for the search of high-mass stars toward RCW 120.
Published: 2019

34. Bipolar H ii regions produced by cloud-cloud collisions

Author: Whitworth, Anthony, Lomax, Oliver, Balfour, Scott, Mège, Pierre, Zavagno, Annie, and Deharveng, Lise
Published: 2018

35. A Virgo Environmental Survey Tracing Ionised Gas Emission (VESTIGE): III. Star formation in the stripped gas of NGC 4254

Author: Boselli, A., Fossati, M., Cuillandre, J. C., Boissier, S., Boquien, M., Buat, V., Burgarella, D., Consolandi, G., Cortese, L., Côté, P., Côté, S., Durrell, P., Ferrarese, L., Fumagalli, M., Gavazzi, G., Gwyn, S., Hensler, G., Koribalski, B., Roediger, J., Roehlly, Y., Russeil, D., Sun, M., Toloba, E., Vollmer, B., Zavagno, Annie, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), 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), Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), Bordeaux population health (BPH), Université de Bordeaux (UB)-Institut de Santé Publique, d'Épidémiologie et de Développement (ISPED)-Institut National de la Santé et de la Recherche Médicale (INSERM), Shanghai Maritime University, Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Sciences, EDP
Subjects: galaxies: clusters: general, galaxies: individual: NGC 4254, galaxies: clusters: individual: Virgo, galaxies: interactions, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: evolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, galaxies: ISM
Abstract: International audience; During pilot observations of the Virgo Environmental Survey Tracing Galaxy Evolution (VESTIGE), a blind narrow-band Hα + [NII] imaging survey of the Virgo cluster carried out with MegaCam at the CFHT, we have observed the spiral galaxy NGC 4254 (M99). Deep Hα + [NII] narrow-band and GALEX UV images reveal the presence of 60 compact (70–500 pc radius) star-forming regions up to ≃20 kpc outside the optical disc of the galaxy. These regions are located along a tail of HI gas stripped from the disc of the galaxy after a rapid gravitational encounter with another Virgo cluster member that simulations indicate occurred 280–750 Myr ago. We have combined the VESTIGE data with multifrequency data from the UV to the far-infrared to characterise the stellar populations of these regions and study the star formation process in an extreme environment such as the tails of stripped gas embedded in the hot intracluster medium. The colour, spectral energy distribution (SED), and linear size consistently indicate that these regions are coeval and have been formed after a single burst of star formation that occurred ≲100 Myr ago. These regions might become free floating objects within the cluster potential well, and be the local analogues of compact sources produced after the interaction of gas-rich systems that occurred during the early formation of clusters.
Published: 2018

36. The effects of ionization feedback on star formation: a case study of the M 16 H II region

Author: Xu, Jin-Long, primary, Zavagno, Annie, additional, Yu, Naiping, additional, Liu, Xiao-Lan, additional, Xu, Ye, additional, Yuan, Jinghua, additional, Zhang, Chuan-Peng, additional, Zhang, Si-Ju, additional, Zhang, Guo-Yin, additional, Ning, Chang-Chun, additional, and Ju, Bing-Gang, additional
Published: 2019
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37. Star formation towards the Galactic H II region RCW 120. Herschel observations of compact sources

Author: Figueira, M., Zavagno, Annie, Deharveng, L., Russeil, D., Anderson, D., Men’shchikov, A., Schneider, N., Hill, T., Motte, F., Mège, P., Leleu, G., Roussel, H., Bernard, P., Traficante, A., Paradis, D., Tigé, J., André, P., Bontemps, Sylvain, Abergel, A., Anderson, L. D., Men'Shchikov, A., Bernard, J.-P., Centro de Matemática e Aplicações Fundamentais (CMAF), Universidade de Lisboa (ULISBOA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN), Department of Medicine - Halifax (DRA), Dalhousie University [Halifax], 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, 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), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Sciences pour l'environnement (SPE), Centre National de la Recherche Scientifique (CNRS)-Université Pascal Paoli (UPP), Cassidian, EADS - European Aeronautic Defense and Space, École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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), Laboratoire arc électrique et plasmas thermiques (LAEPT), Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP), FORMATION STELLAIRE 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), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Université Pascal Paoli (UPP)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centro de Matemática e Aplicações Fundamentais ( CMAF ), Universidade de Lisboa ( ULISBOA ), Laboratoire d'Astrophysique de Marseille ( LAM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Aix Marseille Université ( AMU ) -Centre National d'Etudes Spatiales ( CNES ), Muséum National d'Histoire Naturelle ( MNHN ), Department of Medicine - Halifax ( DRA ), 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, Astrophysique Interactions Multi-échelles ( AIM - UMR 7158 - UMR E 9005 ), Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Paris Diderot - Paris 7 ( UPD7 ), Laboratory for Atmospheric and Space Physics [Boulder] ( LASP ), University of Colorado Boulder [Boulder], Sciences pour l'environnement ( SPE ), Université Pascal Paoli ( UPP ) -Centre National de la Recherche Scientifique ( CNRS ), École pratique des hautes études ( EPHE ), Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de recherche en astrophysique et planétologie ( IRAP ), Université Paul Sabatier - Toulouse 3 ( UPS ) -Observatoire Midi-Pyrénées ( OMP ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire arc électrique et plasmas thermiques ( LAEPT ), Centre National de la Recherche Scientifique ( CNRS ) -Université Blaise Pascal - Clermont-Ferrand 2 ( UBP ), 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 d'astrophysique spatiale ( IAS ), Université Paris-Sud - Paris 11 ( UP11 ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Universidade de Lisboa = University of Lisbon (ULISBOA), 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), École Pratique des Hautes Études (EPHE), 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), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: Physics, stars: formation, 010308 nuclear & particles physics, Infrared, Star formation, Young stellar object, [ SDU.ASTR.GA ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Spectral density, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Stars, H ii regions, Far infrared, ISM: individual objects: RCW 120, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Black-body radiation, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], 010303 astronomy & astrophysics, Envelope (waves)
Abstract: Context. The expansion of H ii regions can trigger the formation of stars. An overdensity of young stellar objects is observed at the edges of H ii regions but the mechanisms that give rise to this phenomenon are not clearly identified. Moreover, it is difficult to establish a causal link between H ii -region expansion and the star formation observed at the edges of these regions. A clear age gradient observed in the spatial distribution of young sources in the surrounding might be a strong argument in favor of triggering. Aims. We aim to characterize the star formation observed at the edges of H ii regions by studying the properties of young stars that form there. We aim to detect young sources, derive their properties and their evolution stage in order to discuss the possible causal link between the first-generation massive stars that form the H ii region and the young sources observed at their edges. Methods. We have observed the Galactic H ii region RCW 120 with Herschel PACS and SPIRE photometers at 70, 100, 160, 250, 350 and 500 μm. We produced temperature and H2 column density maps and use the getsources algorithm to detect compact sources and measure their fluxes at Herschel wavelengths. We have complemented these fluxes with existing infrared data. Fitting their spectral energy distributions with a modified blackbody model, we derived their envelope dust temperature and envelope mass. We computed their bolometric luminosities and discuss their evolutionary stages. Results. The overall temperatures of the region (without background subtraction) range from 15 K to 24 K. The warmest regions are observed towards the ionized gas. The coldest regions are observed outside the ionized gas and follow the emission of the cold material previously detected at 870 μm and 1.3 mm. The H2 column density map reveals the distribution of the cold medium to be organized in filaments and highly structured. Column densities range from 7 × 1021 cm-2 up to 9 × 1023 cm-2 without background subtraction. The cold regions observed outside the ionized gas are the densest and host star formation when the column density exceeds 2 × 1022 cm-2. The most reliable 35 compact sources are discussed. Using existing CO data and morphological arguments we show that these sources are likely to be associated with the RCW 120 region. These sources’ volume densities range from 2 × 105 cm-3 to 108 cm-3. Five sources have envelope masses larger than 50 M⊙ and are all observed in high column density regions (>7 × 1022 cm-2). We find that the evolutionary stage of the sources primarily depends on the density of their hosting condensation and is not correlated with the distance to the ionizing star. Conclusions. The Herschel data, with their unique sampling of the far infrared domain, have allowed us to characterize the properties of compact sources observed towards RCW 120 for the first time. We have also been able to determine the envelope temperature, envelope mass and evolutionary stage of these sources. Using these properties we have shown that the density of the condensations that host star formation is a key parameter of the star-formation history, irrespective of their projected distance to the ionizing stars.
Published: 2017

38. SEDIGISM: Structure, excitation, and dynamics of the inner Galactic interstellar medium

Author: Schuller, F., Csengeri, T., Urquhart, S., Duarte-Cabral, A., Barnes, P. J., Giannetti, A., Hernandez, A. K., Leurini, S., Mattern, M., Medina, S.-N. X., Agurto, C., Azagra, F., Anderson, L. D., Beltrán, M. T., Beuther, H., Bontemps, Sylvain, Bronfman, L., Dobbs, L., Dumke, M., Finger, R., Ginsburg, A., Gonzalez, E., Henning, T., Kauffmann, J., Mac-Auliffe, F., Menten, M., Montenegro-Montes, F. M., Moore, T. J. T., Muller, E., Parra, R., Perez-Beaupuits, P., Pettitt, A., Russeil, D., Sánchez-Monge, Á., Schilke, P., Schisano, E., Suri, S., Testi, L., Torstensson, K., Venegas, P., Wang, K., Wienen, M., Wyrowski, F., Zavagno, Annie, Urquhart, J. S., Dobbs, C. L., Menten, K. M., Perez-Beaupuits, J.-P., Max-Planck-Institut für Radioastronomie (MPIFR), Institut de Veille Sanitaire (INVS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, FORMATION STELLAIRE 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), European Southern Observatory (ESO), Laboratoire de recherche en Electronique, Electrotechnique et Systèmes (L2ES), Institut National de Recherche sur les Transports et leur Sécurité (INRETS)-Université de Technologie de Belfort-Montbeliard (UTBM)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), NASA Goddard Space Flight Center (GSFC), Laboratoire Dynamique de la Biodiversité (LADYBIO), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Haemophilia Unit, Vall d'Hebron University Hospital [Barcelona], Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Physikalisches Institut [Köln], Universität zu Köln, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), University of Oxford [Oxford], School of Physics and Astronomy, University of Exceter, University of Exceter, Millimeter and Submillimeter Astronomy, Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Universität zu Köln = University of Cologne, and University of Oxford
Subjects: Infrared, ISM: structure, Rotational transition, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, ISM: clouds, surveys, 0103 physical sciences, Isotopologue, 010303 astronomy & astrophysics, Galaxy: structure, QC, Astrophysics::Galaxy Astrophysics, QB, Physics, radio lines: ISM, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Galactic plane, Astrophysics - Astrophysics of Galaxies, Galaxy, Interstellar medium, 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], Data reduction
Abstract: The origin and life-cycle of molecular clouds are still poorly constrained, despite their importance for understanding the evolution of the interstellar medium. We have carried out a systematic, homogeneous, spectroscopic survey of the inner Galactic plane, in order to complement the many continuum Galactic surveys available with crucial distance and gas-kinematic information. Our aim is to combine this data set with recent infrared to sub-millimetre surveys at similar angular resolutions. The SEDIGISM survey covers 78 deg^2 of the inner Galaxy (-60 deg < l < +18 deg, |b| < 0.5 deg) in the J=2-1 rotational transition of 13CO. This isotopologue of CO is less abundant than 12CO by factors up to 100. Therefore, its emission has low to moderate optical depths, and higher critical density, making it an ideal tracer of the cold, dense interstellar medium. The data have been observed with the SHFI single-pixel instrument at APEX. The observational setup covers the 13CO(2-1) and C18O(2-1) lines, plus several transitions from other molecules. The observations have been completed. Data reduction is in progress, and the final data products will be made available in the near future. Here we give a detailed description of the survey and the dedicated data reduction pipeline. Preliminary results based on a science demonstration field covering -20 deg < l < -18.5 deg are presented. Analysis of the 13CO(2-1) data in this field reveals compact clumps, diffuse clouds, and filamentary structures at a range of heliocentric distances. By combining our data with data in the (1-0) transition of CO isotopologues from the ThrUMMS survey, we are able to compute a 3D realization of the excitation temperature and optical depth in the interstellar medium. Ultimately, this survey will provide a detailed, global view of the inner Galactic interstellar medium at an unprecedented angular resolution of ~30"., 30 pages. Accepted for publication in A&A. Abstract slightly shortened due to arXiv requirements
Published: 2017
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39. High-mass Star Formation through Filamentary Collapse and Clump-fed Accretion in G22

Author: Yuan, Jinghua, primary, Li, Jin-Zeng, additional, Wu, Yuefang, additional, Ellingsen, Simon P., additional, Henkel, Christian, additional, Wang, Ke, additional, Liu, Tie, additional, Liu, Hong-Li, additional, Zavagno, Annie, additional, Ren, Zhiyuan, additional, and Huang, Ya-Fang, additional
Published: 2017
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40. Herschel observations of the Galactic H II region RCW79

Author: Liu, Hong-Li, Figueira, Miguel, Zavagno, Annie, Hill, Tracey, Schneider, Nicola, Men'shchikov, Alexander, Russeil, Delphine, Motte, Frederique, Tige, Jeremy, Deharveng, Lise, Anderson, Loren D., Li, Jin-Zeng, Wu, Yuefang, Yuan, Jing-Hua, Huang, Maohai, Liu, Hong-Li, Figueira, Miguel, Zavagno, Annie, Hill, Tracey, Schneider, Nicola, Men'shchikov, Alexander, Russeil, Delphine, Motte, Frederique, Tige, Jeremy, Deharveng, Lise, Anderson, Loren D., Li, Jin-Zeng, Wu, Yuefang, Yuan, Jing-Hua, and Huang, Maohai
Abstract: Context. Triggered star formation around H II regions could be an important process. The Galactic H II region RCW79 is a prototypical object for triggered high-mass star formation. Aims. We aim to obtain a census of the young stellar population observed at the edges of the H II region and to determine the properties of the young sources in order to characterize the star formation processes that take place at the edges of this ionized region. Methods. We take advantage of Herschel data from the surveys HOBYS, Evolution of Interstellar Dust, and Hi-Gal to extract compact sources. We use the algorithm getsources. We complement the Herschel data with archival 2MASS, Spitzer, and WISE data to determine the physical parameters of the sources (e. g., envelope mass, dust temperature, and luminosity) by fitting the spectral energy distribution. Results. We created the dust temperature and column density maps along with the column density probability distribution function (PDF) for the entire RCW79 region. We obtained a sample of 50 compact sources in this region, 96% of which are situated in the ionization-compressed layer of cold and dense gas that is characterized by the column density PDF with a double-peaked lognormal distribution. The 50 sources have sizes of similar to 0.1-0.4 pc with a typical value of similar to 0 : 2 pc, temperatures of similar to 11-26 K, envelope masses of similar to 6 760 M-circle dot, densities of similar to 0.1 44 +/- 10(5) cm(3), and luminosities of similar to 19-12712 L-circle dot. The sources are classified into 16 class 0, 19 intermediate, and 15 class I objects. Their distribution follows the evolutionary tracks in the diagram of bolometric luminosity versus envelope mass (L-bol-M-env) well. A mass threshold of 140 M fi, determined from the L-bol-M-env diagram, yields 12 candidate massive dense cores that may form high-mass stars. The core formation efficiency (CFE) for the 8 massive condensations shows an increasing trend of the CFE with
Published: 2017

41. Hi-GAL, the Herschel infrared Galactic Plane Survey: photometric maps and compact source catalogues First data release for the inner Milky Way:+68 degrees \textgreater= l \textgreater=-70 degrees

Author: MOLINARI, S., SCHISANO, E., ELIA, D., PESTALOZZI, M., TRAFICANTE, A., PEZZUTO, S., SWINYARD, B. M., NORIEGA-CRESPO, A., BALLY, J., MOORE, T. J. T., PLUME, R., ZAVAGNO, Annie, GIORGIO, A. M., LIU, S. J., PILBRATT, G. L., MOTTRAM, J. C., RUSSEIL, D., PIAZZO, L., VENEZIANI, M., BENEDETTINI, M., CALZOLETTI, L., FAUSTINI, F., NATOLI, P., PIACENTINI, F., MERELLO, M., PALMESE, A., DEL GRANDE, R., POLYCHRONI, D., RYG, K. L. J., POLENTA, G., BARLOW, M. J., BERNARD, J. -P., MARTIN, P. G., TESTI, L., ALI, B., ANDRÉ, P., BELTRAN, M. T., BILLOT, N., CAREY, S., CESARONI, R., COMPIÈGNE, M., EDEN, D., FUKUI, Y., GARCIA-LARIO, P., HOARE, M. G., HUANG, M., JONCAS, G., LIM, T. L., LORD, . D., MARTINAVARRO-ARMENGOL, S., MOTTE, F., PALADINI, R., PARADIS, D., PERETTO, N., ROBITAILLE, T., SCHILKE, P., SCHNEIDER, N., SCHULZ, B., SIBTHORPE, B., STRAFELLA, F., THOMPSON, M. A., UMANA, G., WARD-THOMPSON, D., WYROWSKI, F., INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Faculty of Informatics [Lugano], Università della Svizzera italiana = University of Italian Switzerland (USI), Space Telescope Science Institute (STSci), Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Department of Physics and Astronomy [Calgary], University of Calgary, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), INAF - Osservatorio Astrofisico di Arcetri (OAA), École Nationale Supérieure d’Agronomie [Alger] (ENSA), 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), Centre National de la Recherche Scientifique (CNRS), Laboratoire d’Optique Atmosphérique - UMR 8518 (LOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Astrophysics [Nagoya], Nagoya University, ISO Data Centre (ESA - Espagne), Herschel Science Centre (ESA Espagne), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), 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, Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, University Hospital of Cologne [Cologne], FORMATION STELLAIRE 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), SRON Netherlands Institute for Space Research (SRON), AUTRES, Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Max-Planck-Institut für Radioastronomie (MPIFR), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), European Space Agency (ESA), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), 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 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), Universität zu Köln, Università della Svizzera italiana (USI), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Aims. We present the first public release of high-quality data products (DR1) from Hi-GAL, the Herschel infrared Galactic Plane Survey. Hi-GAL is the keystone of a suite of continuum Galactic plane surveys from the near-IR to the radio and covers five wavebands at 70, 160, 250, 350 and 500 mu m, encompassing the peak of the spectral energy distribution of cold dust for 8 less than or similar to T less than or similar to 50 K. This first Hi-GAL data release covers the inner Milky Way in the longitude range 68 degrees greater than or similar to l greater than or similar to -70 degrees in a vertical bar b vertical bar \textless= 1 degrees latitude strip. Methods. Photometric maps have been produced with the ROMAGAL pipeline, which optimally capitalizes on the excellent sensitivity and stability of the bolometer arrays of the Herschel PACS and SPIRE photometric cameras. It delivers images of exquisite quality and dynamical range, absolutely calibrated with Planck and IRAS, and recovers extended emission at all wavelengths and all spatial scales, from the point-spread function to the size of an entire 2 degrees x 2 degrees “tile” that is the unit observing block of the survey. The compact source catalogues were generated with the CuTEx algorithm, which was specifically developed to optimise source detection and extraction in the extreme conditions of intense and spatially varying background that are found in the Galactic plane in the thermal infrared. Results. Hi-GAL DR1 images are cirrus noise limited and reach the 1 sigma-rms predicted by the Herschel Time Estimators for parallel-mode observations at 60 `' s(-1) scanning speed in relatively low cirrus emission regions. Hi-GAL DR1 images will be accessible through a dedicated web-based image cutout service. The DR1 Compact Source Catalogues are delivered as single-band photometric lists containing, in addition to source position, peak, and integrated flux and source sizes, a variety of parameters useful to assess the quality and reliability of the extracted sources. Caveats and hints to help in this assessment are provided. Flux completeness limits in all bands are determined from extensive synthetic source experiments and greatly depend on the specific line of sight along the Galactic plane because the background strongly varies as a function of Galactic longitude. Hi-GAL DR1 catalogues contain 123210, 308509, 280685, 160972, and 85460 compact sources in the five bands.
Published: 2016

42. Galactic cold cores

Author: Montillaud, J., Juvela, M., Rivera-Ingraham, A., Malinen, J., Pelkonen, V.-M., Ristorcelli, I., Montier, L., Marshall, D. J., Marton, G., Pagani, L., Tóth, L. V., Zahorecz, S., Ysard, N., McGehee, P., Paladini, R., Falgarone, E., Bernard, J.-P., Motte, F., Zavagno, Annie, Doi, Y., Pelkonen, M., Marshall, J., Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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)-Université Fédérale Toulouse Midi-Pyrénées-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), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Department of Physics [Helsinki], Falculty of Science [Helsinki], Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Centre d'étude spatiale des rayonnements (CESR), 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)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Universiti Brunei Darussalam, Biology Department, Universitii Brunei Darussalam, Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), 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), Eötvös Loránd University (ELTE), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), 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), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), University of Helsinki, University of Helsinki-University of Helsinki, 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)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), 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)-École normale supérieure - Paris (ENS Paris), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: stars: formation, [SDU]Sciences of the Universe [physics], submillimeter: ISM, ISM: clouds, catalogs
Abstract: International audience; Context. For the project Galactic cold cores, Herschel photometric observations were carried out as a follow-up of cold regions of interstellar clouds previously identified with the Planck satellite. The aim of the project is to derive the physical properties of the population of cold sources and to study its connection to ongoing and future star formation. Aims: We build a catalogue of cold sources within the clouds in 116 fields observed with the Herschel PACS and SPIRE instruments. We wish to determine the general physical characteristics of the cold sources and to examine the correlations with their host cloud properties. Methods: From Herschel data, we computed colour temperature and column density maps of the fields. We estimated the distance to the target clouds and provide both uncertainties and reliability flags for the distances. The getsources multiwavelength source extraction algorithm was employed to build a catalogue of several thousand cold sources. Mid-infrared data were used, along with colour and position criteria, to separate starless and protostellar sources. We also propose another classification method based on submillimetre temperature profiles. We analysed the statistical distributions of the physical properties of the source samples. Results: We provide a catalogue of ~4000 cold sources within or near star forming clouds, most of which are located either in nearby molecular complexes (≲1 kpc) or in star forming regions of the nearby galactic arms (~2 kpc). About 70% of the sources have a size compatible with an individual core, and 35% of those sources are likely to be gravitationally bound. Significant statistical differences in physical properties are found between starless and protostellar sources, in column density versus dust temperature, mass versus size, and mass versus dust temperature diagrams. The core mass functions are very similar to those previously reported for other regions. On statistical grounds we find that gravitationally bound sources have higher background column densities (median Nbg(H2) ~ 5 × 1021 cm-2) than unbound sources (median Nbg(H2) ~ 3 × 1021 cm-2). These values of Nbg(H2) are higher for higher dust temperatures of the external layers of the parent cloud. However, only in a few cases do we find clear Nbg(H2) thresholds for the presence of cores. The dust temperatures of cloud external layers show clear variations with galactic location, as may the source temperatures. Conclusions: Our data support a more complex view of star formation than in the simple idea of a column density threshold. They show a clear influence of the surrounding UV-visible radiation on how cores distribute in their host clouds with possible variations on the Galactic scale. Planck (http://www.esa.int/Planck) is a project of the European Space Agency - ESA - with instruments provided by two scientific consortia funded by ESA member states (in particular the lead countries: France and Italy) with contributions from NASA (USA), and telescope reflectors provided in a collaboration between ESA and a scientific consortium led and funded by Denmark.Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Full Table B.1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/584/A92
Published: 2015

43. High-mass Starless Clumps in the Inner Galactic Plane: The Sample and Dust Properties

Author: Yuan, Jinghua, primary, Wu, Yuefang, additional, Ellingsen, Simon P., additional, II, Neal J. Evans, additional, Henkel, Christian, additional, Wang, Ke, additional, Liu, Hong-Li, additional, Liu, Tie, additional, Li, Jin-Zeng, additional, and Zavagno, Annie, additional
Published: 2017
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44. Herschelobservations of the Galactic H ii region RCW 79

Author: Liu, Hong-Li, primary, Figueira, Miguel, additional, Zavagno, Annie, additional, Hill, Tracey, additional, Schneider, Nicola, additional, Men’shchikov, Alexander, additional, Russeil, Delphine, additional, Motte, Frédérique, additional, Tigé, Jérémy, additional, Deharveng, Lise, additional, Anderson, Loren D., additional, Li, Jin-Zeng, additional, Wu, Yuefang, additional, Yuan, Jing-Hua, additional, and Huang, Maohai, additional
Published: 2017
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45. Herschel(star) SPIRE-FTS observations of RCW 120

Author: Rodon, J. A., Zavagno, Annie, Baluteau, J-P, Habart, E., Koehler, M., Le Bourlot, J., Le Petit, F., Abergel, A., Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-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), 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), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and 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)
Subjects: [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context. The expansion of Galactic H II regions can trigger the formation of a new generation of stars. However, little is know about the physical conditions that prevail in these regions. Aims. We study the physical conditions that prevail in specific zones towards expanding H II regions that trace representative media such as the photodissociation region, the ionized region, and condensations with and without ongoing star formation. Methods. We use the SPIRE Fourier Transform Spectrometer (FTS) on board Herschel to observe the H II region RCW 120. Continuum and lines are observed in the 190-670 mu m range. Line intensities and line ratios are obtained and used as physical diagnostics of the gas. We used the Meudon PDR code and the RADEX code to derive the gas density and the radiation field at nine distinct positions including the PDR surface and regions with and without star-formation activity. Results. For the different regions we detect the atomic lines [NII] at 205 mu m and [CI] at 370 and 609 mu m, the (CO)-C-12 ladder between the J = 4 and J = 13 levels and the (CO)-C-13 ladder between the J = 5 and J = 14 levels, as well as CH+ in absorption. We find gas temperatures in the range 45-250 K for densities of 10(4) - 10(6) cm(-3), and a high column density on the order of N-H similar to 10(22) cm(-2) that is in agreement with dust analysis. The ubiquitousness of the atomic and CH+ emission suggests the presence of a low-density PDR throughout RCW 120. High-excitation lines of CO indicate the presence of irradiated dense structures or small dense clumps containing young stellar objects, while we also find a less dense medium (N-H similar to 10(20) cm(-2)) with high temperatures (80-200 K).
Published: 2015

46. Star formation in the filament of S254-S258 OB complex: a cluster in the process of making

Author: Samal, M. R., Ojha, D. K., Jose, J., Zavagno, Annie, Takahashi, S., Neichel, B., Kim, J. S., Chauhan, N., Pandey, A. K., Zinchenko, I., Tamura, M., Ghosh, S. K., Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Tata Institute for Fundamental Research (TIFR), Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Steward Observatory, University of Arizona, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Aryabhatta Research Institute of Observational Sciences, Aryabhatta Research Institute of Observational Sciences (ARIES), Institute of Applied Physics of RAS, Russian Academy of Sciences [Moscow] (RAS), National Astronomical Observatory of Japan (NAOJ), and National Centre for Radio Astrophysics [Pune] (NCRA)
Subjects: filament, Astrophysics of Galaxies (astro-ph.GA), infrared, individual: S254-S258 complex, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Astrophysics of Galaxies, young stellar objects, Astrophysics::Galaxy Astrophysics, star formation, dark cloud
Abstract: Infrared Dark Clouds are ideal laboratories to study the initial processes of high-mass star and star cluster formation. We investigated star formation activity of an unexplored filamentary dark cloud (~5.7pc x 1.9pc), which itself is part of a large filament (~20pc) located in the S254-S258 OB complex at a distance of 2.5kpc. Using MIPS Spitzer 24 micron data, we uncover 49 sources with SNR greater than 5. We identified 45 sources as candidate YSOs of Class I, Flat-spectrum & Class II nature. Additional 17 candidate YSOs (9 Class I & 8 Class II) are also identified using JHK and WISE photometry. We find that the protostar to Class II sources ratio (~2) and the protostar fraction (~70%) of the region are high. When the protostar fraction compared to other young clusters, it suggests that the star formation in the dark cloud was possibly started only 1 Myr ago. Combining the NIR photometry of the YSO candidates with the theoretical evolutionary models, we infer that most of the candidate YSOs formed in the dark cloud are low-mass (, 14 pages, 9 figures, Accepted by Astronomy & Astrophysics
Published: 2015

47. Pillars and globules at the edges of H ii regions

Author: Tremblin, Pascal, Minier, V., Schneider, N., Audit, E., Hill, T., Didelon, P., Peretto, N., Arzoumanian, D., Motte, F., Zavagno, Annie, Bontemps, Sylvain, Anderson, L. D., André, Ph., Bernard, J. P., Csengeri, T., Di Francesco, J., Elia, D., Hennemann, M., Könyves, V., Marston, A. P., Nguyen Luong, Q., Rivera-Ingraham, A., Roussel, Hervé, Sousbie, T., Spinoglio, L., White, G. J., Williams, J., 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), 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), and 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)
Subjects: ISM: kinematics and dynamics, HII regions, ISM: individual objects: Rosette, ISM: individual objects: M 16, ISM: structure, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: International audience; Context. Herschel far-infrared imaging observations have revealed the density structure of the interface between H ii regions and molecular clouds in great detail. In particular, pillars and globules are present in many high-mass star-forming regions, such as the Eagle nebula (M 16) and the Rosette molecular cloud, and understanding their origin will help characterize triggered star formation.Aims. The formation mechanisms of these structures are still being debated. The initial morphology of the molecular cloud and its turbulent state are key parameters since they generate deformations and curvatures of the shell during the expansion of the H ii region. Recent numerical simulations have shown how pillars can arise from the collapse of the shell in on itself and how globules can be formed from the interplay of the turbulent molecular cloud and the ionization from massive stars. The goal here is to test this scenario through recent observations of two massive star-forming regions, M 16 and the Rosette molecular cloud.Methods. First, the column density structure of the interface between molecular clouds and associated H ii regions was characterized using column density maps obtained from far-infrared imaging of the Herschel HOBYS key programme. Then, the DisPerSe algorithm was used on these maps to detect the compressed layers around the ionized gas and pillars in different evolutionary states. Column density profiles were constructed. Finally, their velocity structure was investigated using CO data, and all observational signatures were tested against some distinct diagnostics established from simulations.Results. The column density profiles have revealed the importance of compression at the edge of the ionized gas. The velocity properties of the structures, i.e. pillars and globules, are very close to what we predict from the numerical simulations. We have identified a good candidate of a nascent pillar in the Rosette molecular cloud that presents the velocity pattern of the shell collapsing on itself, induced by a high local curvature. Globules have a bulk velocity dispersion that indicates the importance of the initial turbulence in their formation, as proposed from numerical simulations. Altogether, this study re-enforces the picture of pillar formation by shell collapse and globule formation by the ionization of highly turbulent clouds.
Published: 2013

48. INTERACTIONS OF THE INFRARED BUBBLE N4 WITH ITS SURROUNDINGS

Author: Liu, Hong-Li, primary, Li, Jin-Zeng, additional, Wu, Yuefang, additional, Yuan, Jing-Hua, additional, Liu, Tie, additional, Dubner, G., additional, Paron, S., additional, Ortega, M. E., additional, Molinari, Sergio, additional, Huang, Maohai, additional, Zavagno, Annie, additional, Samal, Manash R., additional, Huang, Ya-Fang, additional, and Zhang, Si-Ju, additional
Published: 2016
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49. Calibration of the AKARI Far-Infrared Imaging Fourier-Transform Spectrometer

Author: 村上, 紀子, 川田, 光伸, 高橋, 英則, 岡田, 陽子, 安田, 晃子, 大坪, 貴文, 金田, 英宏, 松尾, 宏, Baluteau, Jean-Paul, Davis-Imhof, Peter, Gom, Brad G., Naylor, David A., Zavagno, Annie, 山村, 一誠, 松浦, 周二, 白旗, 麻衣, 土井, 靖生, 中川, 貴雄, 芝井, 広, Murakami, Noriko, Kawada, Mitsunobu, Takahashi, Hidenori, Okada, Yoko, Yasuda, Akiko, Ootsubo, Takafumi, Kaneda, Hidehiro, Matsuo, Hiroshi, Yamamura, Issei, Matsuura, Shuji, Shirahata, Mai, Doi, Yasuo, Nakagawa, Takao, Shibai, Hiroshi, 村上, 紀子, 川田, 光伸, 高橋, 英則, 岡田, 陽子, 安田, 晃子, 大坪, 貴文, 金田, 英宏, 松尾, 宏, Baluteau, Jean-Paul, Davis-Imhof, Peter, Gom, Brad G., Naylor, David A., Zavagno, Annie, 山村, 一誠, 松浦, 周二, 白旗, 麻衣, 土井, 靖生, 中川, 貴雄, 芝井, 広, Murakami, Noriko, Kawada, Mitsunobu, Takahashi, Hidenori, Okada, Yoko, Yasuda, Akiko, Ootsubo, Takafumi, Kaneda, Hidehiro, Matsuo, Hiroshi, Yamamura, Issei, Matsuura, Shuji, Shirahata, Mai, Doi, Yasuo, Nakagawa, Takao, and Shibai, Hiroshi
Abstract: 著者人数: 19名, Accepted: 2010-06-14
Published: 2015

50. The HOBYS Key Program: When Herschel links high-mass star formation to cloud structure

Author: Motte, F., Bontemps, Sylvain, Hennemann, M., Nguyen Luong, Q., Schneider, N., Didelon, P., Zavagno, Annie, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, FORMATION STELLAIRE 2012, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-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), 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), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and 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)
Subjects: IR: Herschel, HII regions, stars: formation, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: structure, submillimeter, dust, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], ISM: clouds
Abstract: International audience; With its unprecedented spatial resolution and high sensitivity in the far-infrared to submillimetre regime, {Herschel} is revolutionizing our understanding of star formation. The HOBYS key program is an {Herschel} mapping survey dedicated to the formation of OB-type stars (Motte, Zavagno, Bontemps et al. 2010; see {http://hobys-herschel.cea.fr}. HOBYS aims at 1) discovering and characterizing the progenitors of high-mass stars, 2) making the link between the latters and their filamentary background, and 3) assessing the importance of triggering. Among the HOBYS highlights is the discovery of ''mini-starburst ridges" defined as high-density dominating filaments supersonically contracting and efficiently forming clusters of high-mass stars. Their existence is predicted by dynamical models of cloud formation such as converging flows and is favoring a (high-mass) star formation scenario involving gas flows and global infall. The present star formation rate measured within these ridges is high enough for these 1-10 pc^2 regions to be considered as miniature and instantaneous models of extragalactic starbursts.
Published: 2012

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