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43 results on '"Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]"'

1. Formation of nitrogen oxides via NO+O2 gas–solid reaction on cold surfaces

Author

Marco Minissale, G. Manicò, François Dulieu, S. Baouche, Audrey Moudens, V. Pirronello, E. Congiu, H. Chaabouni, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Università degli studi di Catania [Catania], Dipartimento di Metodologie Fisiche e Chimiche per l'Ingegneria, École normale supérieure - Paris (ENS-PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Università degli studi di Catania = University of Catania (Unict)

Subjects
[PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Chemistry, Inorganic chemistry, General Physics and Astronomy, Gas solid, 01 natural sciences, Gas phase, Adsorption, 13. Climate action, Atmospheric chemistry, 0103 physical sciences, Molecule, Physical and Theoretical Chemistry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Nitrogen oxides, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

The oxidation of nitrogen monoxide has implications for the complex atmospheric chemistry of Antarctica, as well as for planetary atmospheres. In this study we unveil that O 2 adsorbed on a cold surface reacts with a very high efficiency with NO coming from the gas phase to form NO 2 . Via two molecular beams, O 2 and NO molecules are aimed at a cold (10 K) sample held in a UHV chamber. NO 2 is formed independently of the surface composition and morphology. We show that the NO + O 2 reaction occurs mainly through the direct Eley Rideal mechanism to form nitrogen oxides (NO 2 , N 2 O 3 , N 2 O 4 ).

Published
2013
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2. Action principles for quantum automata and Lorentz invariance of discrete time quantum walks

Author

Fabrice Debbasch, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Quantum Physics, Spinor, 010308 nuclear & particles physics, Manifest covariance, FOS: Physical sciences, General Physics and Astronomy, Equations of motion, Energy–momentum relation, Quantum automaton, Lorentz covariance, Lorentz invariance, 01 natural sciences, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Action (physics), Classical mechanics, Discrete time and continuous time, Action principle, 0103 physical sciences, Energy-momentum conservation, Quantum walk, Quantum Physics (quant-ph), 010306 general physics
Abstract

A discrete action principle for general quantum automata is proposed. This action principle is particularized to Discrete Time Quantum Walks (DTQWs) and then extended into an energy and momentum preserving, manifestly covariant formulation. Space-time coordinates are introduced as new variables of the action and their equations of motion enforce energy and momentum conservation. This guarantees that the proposed action can be used to build future, DTQW-based self-consistent models of spinors interacting with gauge fields. A discrete stress-energy tensor for the DTQW is also obtained by functional differentiation of the action with respect to the gradients of the coordinates viewed as functions of the discrete grid points. The manifest covariance of the formulation highlights the special role played by the grid reference frame in the DTQW dynamics. The main discussion is complemented by three appendices., 14 pages

Published
2019
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3. Experimental study of the interaction of two laser-driven radiative shocks at the PALS laser

Author

R. Dudzak, Manuel Cotelo, Francisco Suzuki-Vidal, Jaroslav Nejdl, Jean Larour, U. Chaulagain, Ouali Acef, M. Kozlová, Pedro Velarde, Jan Dostál, P. Barroso, Chantal Stehlé, J.M. Gil, Rafael L. Rodríguez, Thomas Clayson, Raj Laxmi Singh, M. Krus, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Imperial College London, Czech Academy of Sciences [Prague] (CAS), Institute of Physics of the Czech Academy of Sciences (FZU / CAS), ELI Beamlines, Universidad de Las Palmas de Gran Canaria, University of Las Palmas de Gran Canaria (ULPGC), Instituto de Fusión Nuclear, Universidad Politécnica de Madrid (UPM), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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), Systèmes de Référence Temps Espace (SYRTE), 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)-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)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Royal Society

Subjects
Nuclear and High Energy Physics, Hypersonic speed, Fluids & Plasmas, PLASMAS, CODE, FOS: Physical sciences, Context (language use), Hydrodynamics laser-plasmas, 01 natural sciences, 010305 fluids & plasmas, law.invention, Ion, X-RAY-EMISSION, Physics, Fluids & Plasmas, MAGELLANIC-CLOUDS, DEM L316, law, 0103 physical sciences, Radiative transfer, Spectroscopy, 010303 astronomy & astrophysics, Radiative shocks, Laboratory astrophysics, [PHYS]Physics [physics], Physics, SUPERNOVA-REMNANTS, Science & Technology, 02 Physical Sciences, Radiation, Plasma, Laser, Physics - Plasma Physics, Computational physics, Plasma Physics (physics.plasm-ph), Extreme ultraviolet, Physical Sciences, Atomic physics
Abstract

International audience; Radiative shocks (RS) are complex phenomena which are ubiquitous in astrophysical environments. The study of such hypersonic shocks in the laboratory, under controlled conditions, is of primary interest to understand the physics at play and also to check the ability of numerical simulations to reproduce the experimental results.In this context, we conducted, at the Prague Asterix Laser System facility (PALS), the first experiments dedicated to the study of two counter-propagating radiative shocks propagating at non-equal speeds up to 25–50 km/s in noble gases at pressures ranging between 0.1 and 0.6 bar. These experiments highlighted the interaction between the two radiative precursors. This interaction is qualitatively but not quantitatively described by 1D simulations. Preliminary results obtained with XUV spectroscopy leading to the estimation of shock temperature and ion charge of the plasma are also presented.

Published
2017
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4. Pairwise quantum correlations in four-level quantum dot systems

Author

Sanaa Abaach, Mustapha Faqir, Morad El Baz, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
FOS: Physical sciences, General Physics and Astronomy, Quantum entanglement, 01 natural sciences, Fermi-Hubbard model, 010305 fluids & plasmas, Entanglement, Quantum mechanics, 0103 physical sciences, Coulomb, Quantum information, 010306 general physics, Quantum, Quantum tunnelling, [PHYS]Physics [physics], Physics, Quantum Physics, Quantum dots, Lower bound of concurrence, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Mutual information, Quantum coherence, Quantum dot, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Quantum Physics (quant-ph), Ground state, Coherence (physics)
Abstract

International audience; In this paper we assume quantum dots can be assimilated to Fermi Hubbard sites when the Coulomb interaction between electrons is higher compared to their tunneling. The study of pairwise entanglement in a small size array of quantum dots allows to model each pair as a quadrit-quadrit system (4 × 4 mixed state) instead of the more common and simplistic approach of describing it in quantum information as a qubit-qubit system. We study the effect of Coulomb interaction and temperature on pairwise entanglement as well as on quantum coherence and total correlations. The crucial results of this study are that entanglement resists better the increase in temperature when the Coulomb interaction is stronger. Moreover, we successfully explain the behavior of these correlations in terms of the energy spectrum, namely the ground state degeneracy and the state energy difference.

Published
2021
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5. Collisional excitation of C 2 H(X 2 Σ + ) by para-H 2 ( j = 0): Fine-structure resolved transitions

Author

D. Ben Abdallah, François Lique, Fabrice Dayou, Faouzi Najar, N. Feautrier, A. Spielfiedel, Université de Carthage - University of Carthage, Laboratoire de Spectroscopie Atomique, Moléculaire et Applications (LSAMA), Université de Tunis El Manar (UTM)-Faculté des Sciences Mathématiques, Physiques et Naturelles de Tunis (FST), Université de Tunis El Manar (UTM), 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), Laboratoire Ondes et Milieux Complexes (LOMC), Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), and Normandie Université (NU)-Normandie Université (NU)

Subjects
[PHYS]Physics [physics], Physics, 010304 chemical physics, Structure (category theory), General Physics and Astronomy, 01 natural sciences, Intermolecular interaction, 0103 physical sciences, Potential energy surface, Molecule, Physical and Theoretical Chemistry, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Collisional excitation, ComputingMilieux_MISCELLANEOUS, Excitation
Abstract

a b s t r a c t We report theoretical cross sections and rate coefficients for the collisional excitation of C 2 H(X 2 ! + ) by para-H 2 (j =0). The two molecules are treated as rigid rotors. The intermolecular interaction is described by a two-dimensional potential energy surface (PES) averaged over H 2 orientations and based on RCCSD(T) calculations with aug-cc-pVTZ basis sets plus bond functions. Close-coupling calculations of collisional excitation cross sections for the first 25 fine-structure levels of C 2 H yielded rate coefficients up to 100 K. The results show marked differences with recent excitation rate coefficients determined for C 2 H with He as the collision partner.

Published
2014
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6. Quasi-classical trajectory calculations of cross sections and rate constants for the Si + OH → SiO + H reaction

Author

Maurice Monnerville, Jesús Rubayo-Soneira, Alejandro Rivero-Santamaría, F. Dayou, Instituto Superior de Tecnologias y Ciencias Aplicadas - InSTEC (CUBA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Physico-Chimie Moléculaire Théorique (PCMT), Laboratoire de Physique des Lasers, Atomes et Molécules - UMR 8523 (PhLAM), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Embassy of France in Cuba, CNRS national programme 'Physique et Chimie du Milieu Interstellaire, and École normale supérieure - Paris (ENS-PSL)

Subjects
Range (particle radiation), Reaction rate constant, Chemistry, Potential energy surface, Thermal, Ab initio, General Physics and Astronomy, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Atomic physics, 7. Clean energy, Trajectory (fluid mechanics), Excitation
Abstract

International audience; We report the first theoretical determination of cross sections and rate constants for the Si + OH → SiO + H reaction based on dynamics calculations. Quasi-classical trajectory calculations have been carried out for several rotational states of OH using an ab initio potential energy surface recently developed for the X2A′ ground electronic state of SiOH/HSiO. The cross sections behave with collision energies as expected for a barrierless reaction and are slightly sensitive to the rotational excitation of OH. The thermal rate constants evaluated over the range 10–1000 K show a marked temperature dependence below 200 K with a maximum value of 4.3 × 10−10 cm3 s−1 at 20 K.

Published
2014
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7. Quantum walks in artificial electric and gravitational fields

Author

Giuseppe, Di Molfetta, Di Molfetta, Giuseppe, Brachet, Marc, Debbasch, Fabrice, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de l'ENS (LPTENS), 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 Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Informatique et Systèmes (LIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Laboratoire de Physique Théorique de l'ENS [École Normale Supérieure] (LPTENS), and 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)

Subjects
FOS: Computer and information sciences, Statistics and Probability, Computer Science - Information Theory, Quantum dynamics, FOS: Physical sciences, General Relativity and Quantum Cosmology (gr-qc), 01 natural sciences, General Relativity and Quantum Cosmology, 010305 fluids & plasmas, Open quantum system, symbols.namesake, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Gravitational field, 0103 physical sciences, Quantum walk, 010306 general physics, Mathematical Physics, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Physics, Quantum optics, Quantum Physics, Information Theory (cs.IT), Mathematical Physics (math-ph), Condensed Matter Physics, Quantum technology, Dirac fermion, Quantum electrodynamics, symbols, Quantum algorithm, Quantum Physics (quant-ph), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The continuous limit of quantum walks (QWs) on the line is revisited through a recently developed method. In all cases but one, the limit coincides with the dynamics of a Dirac fermion coupled to an artificial electric and/or relativistic gravitational field. All results are carefully discussed and illustrated by numerical simulations., Comment: 13 pages, 3 figures. Submitted to Physica A. arXiv admin note: text overlap with arXiv:1212.5821

Published
2014
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8. Radiative, collisional atomic and Stark broadening data for Ar XII and Ar XIV ions: Quantum mechanical calculations

Author

Sylvie Sahal-Bréchot, Rihab Aloui, Haykel Elabidi, Université de Tunis, Umm Al-Qura University, Université de Carthage - University of Carthage, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Physics, Atmospheres, Stark line broadening, Superstructure, Electron density, Range (particle radiation), Radiation, 010504 meteorology & atmospheric sciences, White dwarfs, Plasma, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, Atomic and Molecular Physics, and Optics, Ion, symbols.namesake, Stark effect, Radiative transfer, symbols, Astrophysics::Solar and Stellar Astrophysics, Atomic physics, Atomic data, Line profiles, Spectroscopy, 0105 earth and related environmental sciences, Line (formation)
Abstract

We present in this work Stark broadening calculations for 12 Ar XII and 12 Ar XIV lines. We present also their radiative atomic and collision data (energy levels, radiative decay rates, line strengths, oscillator strengths and collision strengths). Our Stark broadening data have been obtained using our quantum method in the impact approximation frame and including fine structure effects in the structure study. Our results are provided for the range of temperatures from 5 × 105 to 5 × 106 K of interest for plasmas investigations, and at electron density N e = 10 18 cm − 3 . The radiative atomic data have been calculated using the UCL code SUPERSTRUCTURE. The collision strengths have been calculated using the two UCL codes DISTORTED WAVE and JAJOM. Good agreement have been found between our atomic results and other theoretical and experimental ones. Our Stark broadening data are the first to be published, so no comparisons have been performed for them.

Published
2019
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9. Orbital separation amplification in fragile binaries with evolved components

Author

David Valls-Gabaud, Terry D. Oswalt, Kyle B. Johnston, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)

Subjects
FOS: Computer and information sciences, Proper motion, FOS: Physical sciences, Perturbation (astronomy), Astrophysics, 010501 environmental sciences, Statistics - Applications, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Applications (stat.AP), 010303 astronomy & astrophysics, Instrumentation, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Orbital elements, Physics, Angular distance, White dwarf, Astronomy, Astronomy and Astrophysics, Stars, Distribution function, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Stellar mass loss, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The secular stellar mass-loss causes an amplification of the orbital separation in fragile, common proper motion, binary systems with separations of the order of 1000 A.U. In these systems, companions evolve as two independent coeval stars as they experience negligible mutual tidal interactions or mass transfer. We present models for how post-main sequence mass-loss statistically distorts the frequency distribution of separations in fragile binaries. These models demonstrate the expected increase in orbital seapration resulting from stellar mass-loss, as well as a perturbation of associated orbital parameters. Comparisons between our models and observations resulting from the Luyten survey of wide visual binaries, specifically those containing MS and white-dwarf pairs, demonstrate a good agreement between the calculated and the observed angular separation distribution functions., 37 pages, 13 figures

Published
2012
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10. Temperature dependence of rotational excitation rate coefficients of C2H− in collision with He

Author

N. Feautrier, Fabien Dumouchel, María Luisa Senent, A. Spielfiedel, Laboratoire Ondes et Milieux Complexes (LOMC), Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), 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), Instituto de Estructura de la Materia (IEM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), and École normale supérieure - Paris (ENS Paris)

Subjects
[PHYS]Physics [physics], 010304 chemical physics, Chemistry, General Physics and Astronomy, Collision, 01 natural sciences, 3. Good health, Ion, Coupled cluster, 0103 physical sciences, Potential energy surface, Physical and Theoretical Chemistry, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Excitation
Abstract

From a new two-dimensional Potential Energy Surface (PES), rotational excitation of the C 2H -(X 1Σ +) anion by collision with He is investigated. PES is obtained in the supermolecular approach based on a single and double-excitation coupled cluster method with perturbative contributions from triple excitations (CCSD(T)). Fully-quantum close-coupling calculations of inelastic integral cross sections are done on a grid of collision energies large enough to insure converged state-to-state rate coefficients for the 13 first rotational levels of C 2H - and temperatures ranging from 5 to 100 K. For this collisional system, rate coefficients exhibit a strong propensity in favor of even ΔN transitions. © 2012 Elsevier B.V. All rights reserved., M.L. Senent acknowledges the MICINN (Spain) for the Grant No. AYA2008-00446. Part of the calculations were performed at the IDRIS-CNRS French national computing center under Project No. 2010040883.

Published
2012
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11. Size effects on cation heats of formation. I. Methyl substitutions in nitrogenous compounds

Author

Sydney Leach, 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), and École normale supérieure - Paris (ENS Paris)

Subjects
[PHYS]Physics [physics], 010304 chemical physics, education, Inorganic chemistry, Imine, General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, Standard enthalpy of formation, 0104 chemical sciences, Ion, chemistry.chemical_compound, chemistry, 0103 physical sciences, Polymer chemistry, Molecule, Ammonium, Amine gas treating, Physical and Theoretical Chemistry, Ionization energy, Formamides, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], ComputingMilieux_MISCELLANEOUS
Abstract

The heats of formation of molecular ions are often not known to better than 10 or 20 kJ/mol. The present study on nitrogenous compounds adopts the graphical approach of Holmes and Lossing [8] which relates cation heats of formation to cation size. A study of methyl substitution in formamides and acetamides is followed by an examination of heat of formation data on carbon-site and nitrogen-site methyl substitution in immonium, amine, imine, ammonium and amino cations. The results provide tests of the validity of this graphical method and also suggest investigating or re-investigating the ionization energies and the heats of formation of several of the molecules studied.

Published
2012
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12. High dynamic-range radio-interferometric images at 327 MHz

Author

Juan M. Uson, William D. Cotton, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)

Subjects
Point spread function, 010504 meteorology & atmospheric sciences, Aperture synthesis, FOS: Physical sciences, Energy Engineering and Power Technology, 01 natural sciences, Optics, 0103 physical sciences, Chromatic aberration, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, High dynamic range, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Physics, Dynamic range, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, General Engineering, Refraction, Interferometry, Deconvolution, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business
Abstract

Radio astronomical imaging using aperture synthesis telescopes requires deconvolution of the point spread function as well as calibration of the instrumental characteristics (primary beam) and foreground (ionospheric/atmospheric) effects. These effects vary in time and also across the field of view, resulting in directionally-dependent (DD), time-varying gains. The primary beam will deviate from the theoretical estimate in real cases at levels that will limit the dynamic range of images if left uncorrected. Ionospheric electron density variations cause time and position variable refraction of sources. At low frequencies and sufficiently high dynamic range this will also defocus the images producing error patterns that vary with position and also with frequency due to the chromatic aberration of synthesis telescopes. Superposition of such residual sidelobes can lead to spurious spectral signals. Field-based ionospheric calibration as well as "peeling" calibration of strong sources leads to images with higher dynamic range and lower spurious signals but will be limited by sensitivity on the necessary short-time scales. The results are improved images although some artifacts remain., Comment: to appear in Comptes Rendus Physique (2011)

Published
2012
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13. Sub-millimetre wave radiometry for cloud and rain characterization: From simulation to Earth observation mission concept

Author

Eric Defer, Catherine Prigent, Carlos Jimenez, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Universidad de Antioquia = University of Antioquia [Medellín, Colombia], and École normale supérieure - Paris (ENS-PSL)

Subjects
Earth observation, Brightness, 010504 meteorology & atmospheric sciences, Meteorology, 0211 other engineering and technologies, Energy Engineering and Power Technology, Cloud computing, 02 engineering and technology, Radiation, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Physics::Atmospheric and Oceanic Physics, 021101 geological & geomatics engineering, 0105 earth and related environmental sciences, Remote sensing, Millimetre wave, [PHYS]Physics [physics], business.industry, General Engineering, Inversion (meteorology), Wavelength, 13. Climate action, Radiometry, Environmental science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business
Abstract

Different studies and instrument/mission proposals have demonstrated the potential of the passive sub-millimetre–millimetre wave (SMMW) radiometry to provide remote measurements for the characterization of clouds and rain. At these wavelengths radiation received by a satellite over ice clouds is dominantly scattered by the ice particles. Vertically integrated ice and water contents, hydrometeor properties and profiles can then be retrieved from the radiometric observations with the use of multi-frequency retrieval schemes based on inversion databases simulating realistic brightness temperatures from in situ or modeled cloud microphysics profiles. Current technological SMMW developments offer new observational perspectives for the characterization of the atmosphere.

Published
2012
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14. Comparison of Fe and Ni opacity calculations for a better understanding of pulsating stellar envelopes

Author

L. Piau, M. Busquet, Ph. Cosse, David P. Kilcrease, J. E. Ducret, J. Harris, Michel Poirier, Joyce A. Guzik, N. H. Magee, Q. Porcherot, Jean-Christophe Pain, Christophe Blancard, G. Loisel, F. Delahaye, Thomas Blenski, Gérald Faussurier, D. Gilles, Franck Gilleron, F. Thais, Sylvaine Turck-Chièze, C. J. Zeippen, S. Bastiani-Ceccotti, 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), Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Matière à Haute Densité d'Energie (MHDE), Institut Rayonnement Matière de Saclay (IRAMIS), 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-Laboratoire Interactions, Dynamiques et Lasers (ex SPAM) (LIDyl), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), DAM Île-de-France (DAM/DIF), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Theoretical Division, Los Alamos National Laboratory (LANL), AWE Reading, ARTEP Inc, 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), Dynamique des milieux interstellaires et plasmas stellaires, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire pour l'utilisation des lasers intenses (LULI), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Radiation, Opacity, Atomic Physics (physics.atom-ph), FOS: Physical sciences, Plasma, Astrophysics, Physics - Plasma Physics, Spectral line, Physics - Atomic Physics, Ion, Plasma Physics (physics.plasm-ph), Stars, Astrophysics - Solar and Stellar Astrophysics, Ionization, Radiative transfer, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Opacity is an important ingredient of the evolution of stars. The calculation of opacity coefficients is complicated by the fact that the plasma contains partially ionized heavy ions that contribute to opacity dominated by H and He. Up to now, the astrophysical community has greatly benefited from the work of the contributions of Los Alamos [1], Livermore [2] and the Opacity Project (OP) [3]. However unexplained differences of up to 50% in the radiative forces and Rosseland mean values for Fe have been noticed for conditions corresponding to stellar envelopes. Such uncertainty has a real impact on the understanding of pulsating stellar envelopes, on the excitation of modes, and on the identification of the mode frequencies. Temperature and density conditions equivalent to those found in stars can now be produced in laboratory experiments for various atomic species. Recently the photo-absorption spectra of nickel and iron plasmas have been measured during the LULI 2010 campaign, for temperatures between 15 and 40 eV and densities of ~3 mg/cm3. A large theoretical collaboration, the "OPAC", has been formed to prepare these experiments. We present here the set of opacity calculations performed by eight different groups for conditions relevant to the LULI 2010 experiment and to astrophysical stellar envelope conditions., 15 pages, 10 figures

Published
2011
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15. Photoionization mass spectrometric studies of N-methyl formamide and N,N′-dimethyl formamide in the 7–18eV photon energy range

Author

Sydney Leach, Helmut Baumgärtel, Norbert Champion, Hans-Werner Jochims, 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), Molécules dans l'Univers, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), and Institut für Physikalische und Theoretische Chemie der Freien Universität Berlin

Subjects
Formamide, Chemical ionization, General Physics and Astronomy, Photoionization, Photochemistry, Atmospheric-pressure laser ionization, Ion, chemistry.chemical_compound, chemistry, Ionization, Physics::Atomic and Molecular Clusters, Physics::Chemical Physics, Physical and Theoretical Chemistry, Ionization energy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Electron ionization
Abstract

International audience; A photoionization mass spectrometric study of N-methyl formamide and N,N'-dimethyl formamide has been made using synchrotron radiation over the photon energy range 8-20 eV. Photoion yield curves were measured for the parent ion in both species and for six fragment ions in N-methyl formamide. Assignments of the fragment ions and the pathways of their formation by dissociative photoionization were made on the basis of ion appearance energies in conjunction with thermochemical data and the results of electron impact mass spectral studies. Our results illuminate aspects of the effects of methylation of formamide on ionization energies and dissociative ionization channels, as well as on the relative order of analogous molecular orbitals. The principal dissociative ionization process in both compounds involves HCO-loss. This neutral product may be formed in an electronic excited state. A comparison between the ionization properties, in particular the heats of formation of the cations, of the methyl derivatives of formamide and acetamide, shows that the ionization energies of the latter require re-investigation.

Published
2010
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16. Sounding of Titan’s atmosphere at submillimeter wavelengths from an orbiting spacecraft

Author

E. Lellouch, Paul Hartogh, A. Coustenis, Mark Allen, S. Vinatier, A. Maestrini, R. Moreno, J. M. Krieg, Samuel Gulkis, Imran Mehdi, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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)-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), Jet Propulsion Laboratory, California Institute of Technology (JPL), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Spacecraft, Terahertz radiation, business.industry, Polar orbit, Astronomy, Astronomy and Astrophysics, Astrobiology, law.invention, symbols.namesake, Orbiter, Depth sounding, Space and Planetary Science, law, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), business, Enceladus, Doppler effect
Abstract

International audience; An investigation of the capabilities and science goals of a submillimeter-wave heterodyne sounder onboard a Titan orbiter is presented. Based on a model of Titan's submillimeter spectrum, and including realistic instrumental performances, we show that passive limb observations of Titan's submillimeter radiation would bring novel and unique information on the dynamical and chemical state of Titan's atmosphere, particularly in the so far poorly probed 500-900 km region. The 300-360, 540-660 and 1080-1280 GHz spectral ranges appear especially promising, and could be explored with an instrument equipped with a tunable local oscillator system. Vertical temperature profiles can be determined up to ˜1200 km using rotational lines of CH 4, CO, and HCN. Winds can be measured over the 200-1200 km altitude range with an accuracy of 3-5 m/s from Doppler shift measurements of any strong optically thin line. Numerous molecular species are accessible, including H 2O, NH 3, CH 3C 2H, CH 2NH, and several nitriles (HC 3N, HC 5N, CH 3CN, and C 2H 3CN). Many of them are expected to be detectable in a large fraction of the atmosphere and in some cases at all levels, providing an observational link between stratospheric and thermospheric chemistry. Isotopic variants of some of these species can also be measured, providing new measurements of H, C, N, and O isotopic ratios. Mapping of the thermal, wind, and composition fields, best achieved from a polar orbit and with an articulated antenna, would provide a new view of the couplings between chemistry and dynamics over an extended altitude range of Titan's atmosphere. Additional science goals at Saturn and Enceladus are briefly discussed.

Published
2010
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17. Schottky diode-based terahertz frequency multipliers and mixers

Author

Jeanne Treuttel, Goutam Chattopadhyay, G. Beaudin, Cecile Jung, Hui Wang, Bertrand Thomas, Yong Jin, Imran Mehdi, Alain Maestrini, Sorbonne Université (SU), Jet Propulsion Laboratory, California Institute of Technology (JPL), STFC Rutherford Appleton Laboratory, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), 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), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Physics, Fabrication, Terahertz radiation, business.industry, Frequency multiplier, Superheterodyne receiver, General Engineering, Energy Engineering and Power Technology, Schottky diode, law.invention, Planar, law, Optoelectronics, Heterodyne detection, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], business, Planar diode
Abstract

International audience; This article presents some aspects of the technology of terahertz heterodyne receiver front-ends dedicated to astrophysics, planetary and atmospheric sciences. It focuses on frequency multipliers and on Schottky mixers. Novel architectures of power-combined frequency multipliers at submillimeter-wavelengths, THz planar fundamental mixers, and integrated receivers will be discussed, as well as the fabrication of submillimeter-wave planar Schottky diodes in France.

Published
2010
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18. Millimeter and submillimeter measurements of asteroid (2867) Steins during the Rosetta fly-by

Author

Emmanuel Lellouch, P. J. Encrenaz, Peter Schloerb, Dominique Bockelée-Morvan, Nicolas Biver, Wing-Huen Ip, Ingrid Mann, C. Backus, M. A. Janssen, Gerard Beaudin, Paul Hartogh, Margaret A. Frerking, Stephen Keihm, L. W. Kamp, Seungwon Lee, T. Encrenaz, Mark Hofstadter, Björn Davidsson, Thomas R. Spilker, Jacques Crovisier, Samuel Gulkis, Jet Propulsion Laboratory, California Institute of Technology (JPL), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), 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), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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)-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), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Department of Earth and Planetary Science, Faculty of Science, Kobe University, and Five College Radio Astronomy Observatory, University of Massachusetts

Subjects
Physics, Radiometer, Spectrometer, Parabolic reflector, Astronomy, Astronomy and Astrophysics, law.invention, Telescope, Orbiter, Space and Planetary Science, law, Asteroid, Radiative transfer, Emissivity, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The European Space Agency Rosetta Spacecraft passed within 803 km of the main belt asteroid (2867) Steins on 5 September 2008. The Rosetta Spacecraft carries a number of scientific instruments including a millimeter and submillimeter radiometer and spectrometer. The instrument, named MIRO (Microwave Instrument for the Rosetta Orbiter), consists of a 30-cm diameter, offset parabolic reflector telescope followed by two heterodyne receivers. Center-band operating frequencies of the receivers are near 190 GHz (1.6 mm) and 562 GHz (0.53 mm). Broadband continuum channels are implemented in both frequency bands for the measurement of near surface temperatures and temperature gradients. A 4096 channel CTS (chirp transform spectrometer) having 180 MHz total bandwidth and ˜44 kHz resolution is also connected to the submillimeter receiver. We present the continuum observations of asteroid (2867) Steins obtained during the fly-by with the MIRO instrument. Spectroscopic data were also collected during the fly-by using the MIRO spectrometer fixed-tuned to rotational lines of several molecules. Results of the spectroscopic investigation will be the topic of a separate publication. Comparative thermal models and radiative transfer calculations for Steins are presented. Emissivities of Steins were determined to be 0.6-0.7 and 0.85-0.9 at wavelengths of 0.53 and 1.6 mm, respectively. The thermal inertia of Steins was estimated to be in the range 450-850 J/(m 2 s 0.5 K). Assuming that the emissivity of Steins is determined by the Fresnel reflection coefficients of the surface material, the area-averaged dielectric constant of the surface material is in the range 4-20. These values are rock-like, and are unlike the powdered-regolith surface of the Moon.

Published
2010
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19. Precipitation retrieval from space: An overview

Author

Catherine Prigent, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Global and Planetary Change, Meteorology, Infrared, Satellite remote sensing, General Earth and Planetary Sciences, Sampling (statistics), Environmental science, Satellite, Precipitation, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Microwave, Remote sensing
Abstract

International audience; During the last decade, satellite observations have allowed significant advances in quantifying precipitation, especially with the contribution of the TRMM mission. Observations at different wavelengths (visible, infrared, and microwaves), in both active and passive microwave modes, are analyzed, and eventually coupled to produce records of precipitation estimates over the globe, with up to hourly time sampling. This article provides an overview of the techniques, the results and the perspectives.

Published
2010
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20. Accurate potential energy functions and non-adiabatic couplings in the Mg+H system

Author

Marie Guitou, N. Feautrier, A. Spielfiedel, Laboratoire de Modélisation et Simulation Multi Echelle (MSME), Université Paris-Est Marne-la-Vallée (UPEM)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), 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), and École normale supérieure - Paris (ENS Paris)

Subjects
[PHYS]Physics [physics], 010304 chemical physics, Chemistry, General Physics and Astronomy, 01 natural sciences, Potential energy, Dissociation (chemistry), Astronomical spectroscopy, Dipole, Active space, 0103 physical sciences, Radiative transfer, Molecule, Physical and Theoretical Chemistry, Atomic physics, 010306 general physics, Adiabatic process
Abstract

International audience; Potential energy functions of the MgH molecule are investigated by the MRCI method using large active space and basis sets. The calculations are performed up to the Mg(3s3d, 1D) + H dissociation limit. The molecular constants compare well with the available data. The dipole moment functions exhibit a series of crossings due to the strong interactions between the states. Radial and rotational couplings among these states are also calculated, with a state-averaged MCSCF approach. This work will enable calculations of collisional cross sections and rate coefficients, important for the modelling of stellar spectra when collisions compete with radiative processes in non-LTE conditions. (C) 2010 Elsevier B. V. All rights reserved.

Published
2010
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21. Improvements to the RADIOM non-LTE model

Author

Denis Colombant, M. Busquet, J. Gardner, M. Klapisch, David Fyfe, ARTEP Inc, 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), Plasma Physics Division, Naval Research Laboratory, Naval Research Laboratory (NRL), Laboratory for Computational Physics and Fluid Dynamics (LCP&FD), and Berkeley Research Associates

Subjects
Physics, Nuclear and High Energy Physics, Radiation, Heuristic, Saha ionization equation, Effective temperature, Computational physics, Distribution (mathematics), Ionization, Excited state, Benchmark (computing), Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Complement (set theory)
Abstract

International audience; In 1993, we proposed the RADIOM model [M. Busquet, Phys. Fluids 85 (1993) 4191] where an ionization temperature T z is used to derive non-LTE properties from LTE data. T z is obtained from an "extended Saha equation" where unbalanced transitions, like radiative decay, give the non-LTE behavior. Since then, major improvements have been made. T z has been shown to be more than a heuristic value, but describes the actual distribution of excited and ionized states and can be understood as an "effective temperature". Therefore we complement the extended Saha equation by introducing explicitly the auto-ionization/dielectronic capture. Also we use the SCROLL model to benchmark the computed values of T z.

Published
2009
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22. Multiscale cosmological dynamics

Author

Claire Chevalier, Fabrice Debbasch, Yann Ollivier, Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), Unité de Mathématiques Pures et Appliquées (UMPA-ENSL), and École normale supérieure de Lyon (ENS de Lyon)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Physics, Gravitation, Gravitational-wave observatory, Amplitude, Gravitational field, Field (physics), Gravitational wave, Quantum mechanics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Condensed Matter Physics, Gravitational acceleration, Gravitational redshift
Abstract

The recently developed mean field theory of relativistic gravitation predicts the emergence of an “apparent matter” field at large scales describing the net effect of small-scale fluctuations on the large-scale dynamics of the universe. It is found that this so-called back reaction effect is much stronger for gravitational waves than for matter density fluctuations. At large scales, gravitational waves behave like radiation and, for them, the perturbative effect scales as the squared relative amplitude times squared frequency. In particular, a bath of gravitational waves of relative amplitude 1 0 − 5 and frequency 1 0 − 12 Hz would not be directly detectable by today’s technology but would generate an effective large-scale radiation of amplitude comparable to the unperturbed matter density of the universe.

Published
2009
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23. From collisional line broadening to atomic polarization and collisional depolarization; Astrophysical applications

Author

S. Sahal-Bréchot, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Zeeman effect, Astronomy, Astronomy and Astrophysics, Polarization (waves), Solar physics, Spectral line, Computational physics, Magnetic field, symbols.namesake, Space and Planetary Science, symbols, Stokes parameters, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, Line (formation)
Abstract

International audience; As is well known, interpretation of spectral line shapes is essential for spectroscopic modeling in the laboratory and in astrophysics. Line broadening by collisions offers a tool for spectroscopic diagnostics of scalar physical quantities, especially densities of perturbers. Thanks to the growing accuracy and sensitivity of spectropolarimetric observations and to the progress of MHD modeling, interpretation of all the Stokes parameters of spectral lines nowadays becomes crucial and new tools leading to the determination of vectorial (or anisotropic) physical quantities have been created and are of increasing interest. In particular, interpretation of atomic polarization enables us to determine magnetic field vectors, velocity field vectors, and also to interpret anisotropic excitation of the atomic levels by collimated beams of energetic particles. Atomic polarization leads to a global polarization of the observed line. It is a consequence of a departure from LTE between the Zeeman sublevels, and is due to an anisotropic excitation of the atomic levels. This anisotropic excitation is often the result of the incident radiation field absorption. However, isotropic collisions between Zeeman sublevels try to restore LTE and to destroy this atomic polarization. So, a quantitative interpretation of these spectropolarimetric observations must take into account collisional depolarization (and also the possible polarization transfer between levels). In some cases, collisional depolarization can also be used for determining densities of perturbers. In fact, collisional line broadening, atomic polarization and collisional theories are two complementary theories based on the same key approximations: "no back reaction" and "impact theory". For collisional widths and shifts, the pioneering work by Baranger created in the end of the fifties, was followed by many fruitful developements. For atomic polarization, the theory of the master equation, was created by Fano in the fifties and developed for polarization studies at the end of the sixties and seventies in the pioneering works by Cohen-Tannoudji and coworkers. It has also been extended by many fertile developments, in particular for astrophysics. The main features of the formalism of atomic polarization and colisional depolarization will be presented in parallel with collisional line broadening and astrophysical applications, especially for solar physics, will be reported.

Published
2009
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24. Interpreting the complex line profiles in the stellar spectra

Author

Milan S. Dimitrijević, Luka Č. Popović, Emmanouel Danezis, Evaggelia Lyratzi, A. Antoniou, Faculty of Physics Department of Astrophysics, Astronomy and Mechanics, University of Athens, Panepistimioupoli, Belgrade Astronomical Observatory, Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Absorption spectroscopy, Astronomy, Astronomy and Astrophysics, Astrophysics, Astronomical spectroscopy, Spectral line, Stars, Full width at half maximum, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Absorption (electromagnetic radiation), Optical depth, Line (formation)
Abstract

International audience; In this review we present our recent investigation of the complex absorption lines in spectra of hot emission stars. The lines are created in a material ejected from stars (here we call it density regions around the objects). Particularly we present a model (GR model) which is developed to study satellite or discrete absorption components (SACs or DACs). Using the model we are able to extract kinematical parameters (rotational, radial and random velocity) and some physical parameters (full width at half maximum, optical depth in the center of the line, column density and absorbed or emitted energy) of the density regions.

Published
2009
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25. Simulations of Fe at 156eV with configuration interaction and mixed UTA

Author

M. Busquet, M. Klapisch, ARTEP Inc, Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Radiation, Nuclear magnetic resonance, Configuration interaction, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectral line, Computational physics
Abstract

International audience; Simulations of the transmission spectra measured by Bailey et al. (Phys. Rev. Lett. 99 (2007) 265002-265004), obtained with the newest version of the HULLAC, are presented. With this new version one can easily define which group of configurations will be computed to synthesize the spectrum. Moreover, one can now compute mixed UTA (MUTA). These modifications provide an extension of the older HULLAC codes. The aim of this work is to compare spectra with different ranges of configuration interactions and with different thresholds for treating separated lines in the MUTA model.

Published
2009
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26. Ab initio potential energy surfaces for the 1A′ and 3A′ states of the MgH(X2Σ+)+H(2S) system

Author

Faouzi Najar, N. Feautrier, A. Spielfiedel, François Lique, D. Ben Abdallah, Z. Ben Lakhdar, Nejm-Eddine Jaidane, Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
[PHYS]Physics [physics], Davidson correction, Chemistry, Ab initio, General Physics and Astronomy, 7. Clean energy, 01 natural sciences, Potential energy, Ab initio quantum chemistry methods, 0103 physical sciences, Atom, Physics::Chemical Physics, Physical and Theoretical Chemistry, Atomic physics, 010306 general physics, Ground state, 010303 astronomy & astrophysics, Legendre polynomials, ComputingMilieux_MISCELLANEOUS, Basis set
Abstract

The two potential energy surfaces (PESs) associated to the 1 A ′ and 3 A ′ states correlating to the interacting MgH(X 2 Σ + ) + H( 2 S) system were determined from ab initio calculations. They were obtained using the aug-cc-pVQZ basis set for the H atom and the cc-pV5Z basis set for the Mg atom and multireference internally contracted configuration-interaction (MRCI) method including Davidson correction. The MgH distance was kept fixed at its experimental equilibrium distance in the X 2 Σ ground state. The ab initio calculated interaction energies of the two PESs were fitted analytically on the basis of Legendre polynomials for future collisional rotational excitation study. The 1 A ′ and 3 A ′ adiabats both present very deep well corresponding to the MgH 2 complex.

Published
2009
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27. Thermal statistical ensembles of classical extreme black holes

Author

Claire Chevalier, Fabrice Debbasch, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Physics, Astrophysics::High Energy Astrophysical Phenomena, White hole, Condensed Matter Physics, Black hole, General Relativity and Quantum Cosmology, Micro black hole, Binary black hole, Quantum mechanics, Extremal black hole, Statistical physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spaghettification, Black hole thermodynamics, Hawking radiation
Abstract

International audience; New statistical ensembles of classical extreme black holes are introduced. Each ensemble is proven to represent a non extreme, finite temperature black hole. This mean or average black hole is surrounded by a mean electromagnetic field and a so-called apparent matter, which is the large scale trace of the averaged upon small scale fluctuations of the gravitational and electromagnetic fields. However, the total mass and the total charge of space-time is not modified by the averaging.

Published
2009
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28. Equilibrium distribution function of a relativistic dilute perfect gas

Author

Fabrice Debbasch, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Physics, Distribution function, Distribution (number theory), Continuum mechanics, Perfect gas, Statistical physics, Quantum field theory, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Condensed Matter Physics, Equilibrium distribution function
Abstract

International audience; An alternative to the Jüttner distribution has been recently proposed by several authors. The literature on the topic is reviewed critically. It is found that the Jüttner distribution is correct and that the alternative distribution contradicts quantum field theory, statistical physics and continuum mechanics.

Published
2008
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29. Stark broadening and hfs of Mn II

Author

Miodrag Dačić, Luka Č. Popović, Sylvie Sahal-Bréchot, Milan S. Dimitrijević, Andjelka Kovačević, Zoran Simić, Belgrade Astronomical Observatory, Department of Astronomy, Faculty of Mathematics, University of Belgrade, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, symbols.namesake, Stark effect, Space and Planetary Science, symbols, Semiclassical physics, Astronomy and Astrophysics, Configuration interaction, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Instrumentation, Spectral line
Abstract

International audience; Large differences between previous calculations of the Mn II spectral line Stark widths [Popovic, L.C., Dimitrijevic, M.S., 1997a. A&AS 128, 203; Popovic, L.C., Dimitrijevic, M.S., 1997b. SAJ 156, 173] and a recent experiment by [Djenize, S., Bukvic, S., Sreckovic, A., Nikolic, Z., 2006. NewA 11, 256] are considered. In order to do so, new semiclassical perturbation calculations of the Stark broadening parameters of three spectral lines within Mn II 3d 54s a 7S-3d 54p z 7P o and three within Mn II 3d 54s a 5S-3d 54p z 5P o multiplets, are performed. The influence of hfs on the Stark broadening parameters determination as a possible reason of disagreement is also discussed, on the example of Mn II 260.6455 nm and 259.4497 nm lines. Namely, measured and calculated values taking into account the hfs effect are compared. We found that this effect cannot explain the large discrepancy between experiment and theory. Other possible reasons for disagreement like the configuration interaction are discussed as well. The new semiclassical perturbation calculations, more sophisticated than previous ones, performed by using the modified semiempirical theory, are in better agreement with experiment, but a large difference up to a factor 2.39 for the width, still exist.

Published
2008
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30. A new algorithm for the solution and analysis of the Collisional Radiative Model equations

Author

M. Busquet, Marcel Klapisch, ARTEP Inc, Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Radiation, Quality (physics), Atomic theory, Atomic model, Radiative transfer, Charge (physics), Function (mathematics), State (functional analysis), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Algorithm, General algorithm
Abstract

International audience; A new general algorithm for the solution of the Collisional Radiative Model (CRM) for large atomic models is presented. It is based on the separation of total population, and reduced populations for the individual states of each charge state. The sum of the latter is unity. This leads to a double linearized coupled iterative system, including cycling on all charge states. This algorithm is robust. It gives insight into the quality of the atomic model by allowing the follow up of the charge states populations, the global rates and the average charge Z* as a function of the iteration index. We show results on Xe with 39,683 configuration states.

Published
2007
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31. Improved analytic fits of collisional cross-sections

Author

M. Busquet, ARTEP Inc, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, High energy, Radiation, Distribution function, Limit (mathematics), Electron, Algebra over a field, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, Numerical integration, Ion
Abstract

Computing collisional cross-sections σ(ɛ), where ɛ is the energy of the incident electron, is costly. Furthermore, for collisional-radiative models the thermally averaged cross-sections 〈σ〉Te integrated over the distribution function of all electron energies is needed, so that one generally fits the collision strength Ω(ɛ) for 5–20 energies ɛi before an analytical or numerical integration is performed. However, in multi-charged, multi-electron ions, it is usual to find poor fits, which can lead to negative rates, for about 20% of the excitation transitions when one employs the classical Goett et al. fit (GCS) Ω ( u = ɛ / Δ E ) = A + D ln ( u ) + c 1 / ( C + u ) + c 2 / ( C + u ) 2 even when using the Bethe limit, also called Born or Coulomb-Born limit, at high energy as a constraint. From examples, we shall derive the requirement for an adequate fit and propose a tractable and efficient algebra to replace the GCS formula.

Published
2007
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32. Thermal statistical ensembles of black holes

Author

Miguel D. Bustamante, Fabrice Debbasch, C. Chevalier, 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), Laboratoire de Physique Statistique de l'ENS (LPS), 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), and 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Statistics and Probability, Physics, Astrophysics::High Energy Astrophysical Phenomena, White hole, Fuzzball, Condensed Matter Physics, Black hole, General Relativity and Quantum Cosmology, Micro black hole, Theoretical physics, Classical mechanics, Binary black hole, Nonsingular black hole models, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Black hole thermodynamics, Hawking radiation
Abstract

ERGA/LERMA Universite Paris VI UMR 8112, 3 rue Galil´ ´ee 94200 Ivry, FranceAbstractWe consider statistical ensembles of Schwarzschild black holes and prove that theseensembles describe black holes of non vanishing temperatures. The mean space-times as-sociated to these ensembles are explored through exact computations of their energy distri-butions, total masses and calorific capacities. We discuss our results, with special emphasison their connections with current and near future observations of astrophysical black holes,string theory and cosmology.Key words: Relativistic statistical physics, black holes.

Published
2007
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33. Cryovolcanic features on Titan's surface as revealed by the Cassini Titan Radar Mapper

Author

G. Boubin, Michael Allison, Ellen R. Stofan, Charles Elachi, G. Hamilton, Steven J. Ostro, L. Roth, Randolph L. Kirk, William T. K. Johnson, Stephen D. Wall, Y. Anderson, S. Shaffer, Roberto Seu, Philip S. Callahan, Lauren Wye, R. Boehmer, Bryan Stiles, Gian Gabriele Ori, Jani Radebaugh, Karl L. Mitchell, Giovanni Picardi, Howard A. Zebker, Laurence A. Soderblom, Duane O. Muhleman, Richard West, S. Vetrella, Enrico Flamini, R. D. Lorenz, Roberto Orosei, Andrew Dominic Fortes, Jonathan I. Lunine, Yonggyu Gim, K. Kelleher, L. E. Robshaw, Catherine D. Neish, E. Reffet, Pierre Encrenaz, Scott Hensley, Flora Paganelli, Michael Janssen, Rosaly M. C. Lopes, Francesco Posa, Charles A. Wood, G. Francescetti, Jet Propulsion Laboratory, California Institute of Technology (JPL), Proxemy Research, Bowie, Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), US Geological Survey, Flagstaff, Wheeling Jesuit University, Environmental Sciences Department, Lancaster University, University College of London [London] (UCL), Goddard Institute for Space Studies, National Aeronautics and Space Administration New York, Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Agenzia Spaziale Italiana (ASI), Facoltá di Ingegneria, Geological and Planetary Sciences, California Institute of Technology, Pasadena, International Research School of Planetary Sciences, Dipartimento di Scienze, Università d'Annunzio, Istituto di Astrofisica Spaziale e Fisica cosmica - Roma (IASF-Roma), Istituto Nazionale di Astrofisica (INAF), Universitá La Sapienza, INFM and Dipartimento Interateneo di Fisica, and Stanford University

Subjects
Synthetic aperture radar, Solar System, geography, satellites of saturn, titan, volcanism, geography.geographical_feature_category, biology, Lava, Astronomy and Astrophysics, Venus, biology.organism_classification, Astrobiology, law.invention, symbols.namesake, Volcano, Space and Planetary Science, law, Radar imaging, symbols, Radar, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Geology
Abstract

International audience; The Cassini Titan Radar Mapper obtained Synthetic Aperture Radar images of Titan's surface during four fly-bys during the mission's first year. These images show that Titan's surface is very complex geologically, showing evidence of major planetary geologic processes, including cryovolcanism. This paper discusses the variety of cryovolcanic features identified from SAR images, their possible origin, and their geologic context. The features which we identify as cryovolcanic in origin include a large (180 km diameter) volcanic construct (dome or shield), several extensive flows, and three calderas which appear to be the source of flows. The composition of the cryomagma on Titan is still unknown, but constraints on rheological properties can be estimated using flow thickness. Rheological properties of one flow were estimated and appear inconsistent with ammonia-water slurries, and possibly more consistent with ammonia-water-methanol slurries. The extent of cryovolcanism on Titan is still not known, as only a small fraction of the surface has been imaged at sufficient resolution. Energetic considerations suggest that cryovolcanism may have been a dominant process in the resurfacing of Titan.

Published
2007
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34. VUV photochemistry of small biomolecules

Author

Sydney Leach, Helmut Baumgärtel, François Dulieu, Martin Schwell, Hans-Werner Jochims, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut für Physikalische und Theoretische Chemie der Freien Universität Berlin, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Formic acid, Biomolecule, Astronomy and Astrophysics, Photochemistry, Mass spectrometry, Fluorescence spectroscopy, Acetic acid, chemistry.chemical_compound, chemistry, Fragmentation (mass spectrometry), Space and Planetary Science, Ionization, Nucleic acid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; We review our recent results on the vacuum ultraviolet (VUV) photochemistry of small biomolecules. The experimental techniques used, mass spectrometry and photofragment fluorescence spectroscopy, are described. Emphasis is laid on our mass spectrometric results obtained for five nucleic acid bases and five amino acids. Ionisation and appearance energies are determined from photoionisation mass spectrometry, many for the first time. From this, fragmentation pathways following 6-22 eV photoexciation are derived. The adiabatic ionisation energies of the biomolecules studied lie between 8.2 eV (adenine) and 9.6 eV ( alpha-amino-isobutyric acid). We show that the nucleic acid monocations, and chemically related molecular cations, do not fragment even when formed with large internal energies ( Eint) ranging from 1.80 to 5.35 eV. In contrast, amino acid monocations are unstable and rapid fragmentation occurs via rupture of the C sbnd C(OOH) bond, except for beta-alanine, where rupture of the bond between the alpha-C and beta-C is the lowest lying ionic dissociation channel. The VUV photochemistry of the prebiotic species formic acid, acetic acid and methylformate, studied in more detail previously by several techniques, including fluorescence spectroscopy, is also reviewed. Astrophysical implications of our work are discussed in the conclusion.

Published
2006
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35. Signatures of TeV scale gravity in cosmic rays

Author

A. Nicolaidis, Norma G. Sanchez, Department of Theoretical Physics, University of Thessaloniki, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Gravity (chemistry), Particle physics, Scattering, Cosmic ray, Gauge (firearms), Atomic and Molecular Physics, and Optics, Gravitation, General Relativity and Quantum Cosmology, Singularity, Brane, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Schwarzschild radius
Abstract

In TeV scale unification models, gravity propagates in 4 + δ dimensions while gauge and matter fields are confined to a four dimensional brane, with gravity becoming strong at the TeV scale. For a such scenario, we study strong gravitational interactions in a effective Schwarzschild geometry. Two distinct regimes appear. For large impact parameters, the ratio ρ ∼ ( R s / r 0 ) 1 + δ , (with R s the Schwarzschild radius and r 0 the closest approach to the black hole), is small and the deflection angle χ is proportional to ρ (this is like Rutherford-type scattering). For small impact parameters, the deflection angle χ develops a logarithmic singularity and becomes infinite for ρ = ρ crit = 2 / ( 3 + δ ) . This singularity is reflected into a strong enhancement of the backward scattering (like a glory-type effect). We suggest as distinctive signature of black hole formation in particle collisions at TeV energies, the observation of backward scattering events and their associated diffractive effects.

Published
2006
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36. The cluster expansion for the self-gravitating gas and the thermodynamic limit

Author

Norma G. Sanchez, H. J. de Vega, Laboratoire de Physique Théorique et Hautes Energies (LPTHE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université 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), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), and De Vega, H J

Subjects
High Energy Physics - Theory, Nuclear and High Energy Physics, Condensed Matter (cond-mat), FOS: Physical sciences, Thermodynamics, Condensed Matter, General Relativity and Quantum Cosmology (gr-qc), Astrophysics, 01 natural sciences, General Relativity and Quantum Cosmology, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Singularity, [PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Critical point (thermodynamics), 0103 physical sciences, 010306 general physics, Physics, Partition function (statistical mechanics), Recurrence relation, [PHYS.GRQC] Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], [PHYS.HTHE]Physics [physics]/High Energy Physics - Theory [hep-th], 010308 nuclear & particles physics, Astrophysics (astro-ph), Grand canonical ensemble, High Energy Physics - Theory (hep-th), [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Thermodynamic limit, [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], [PHYS.HTHE] Physics [physics]/High Energy Physics - Theory [hep-th], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Cluster expansion, Dimensionless quantity
Abstract

We develop the cluster expansion and the Mayer expansion for the self-gravitating thermal gas and prove the existence and stability of the thermodynamic limit N, V to infty with N/V^{1/3} fixed. The essential (dimensionless) variable is here eta = [G m^2 N]/[V^{1/3} T] (which is kept fixed in the thermodynamic limit). We succeed in this way to obtain the expansion of the grand canonical partition function in powers of the fugacity. The corresponding cluster coefficients behave in the thermodynamic limit as [eta/N]^{j-1} c_j where c_j are pure numbers. They are expressed as integrals associated to tree cluster diagrams. A bilinear recurrence relation for the coefficients c_j is obtained from the mean field equations in the Abel form. In this way the large j behaviour of the c_j is calculated. This large j behaviour provides the position of the nearest singularity which corresponds to the critical point (collapse) of the self-gravitating gas in the grand canonical ensemble. Finally, we discuss why other attempts to define a thermodynamic limit for the self-gravitating gas fail., Comment: LaTex 12 pages, 1 figure .ps

Published
2005
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37. Direct observation of the k3Π state of 12C18O

Author

Jacob Baker, Françoise Launay, Division of Environmental Health and Risk Management, School of Geography, Earth, and Environmental Sciences, University of Birmingham, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Absorption band, Chemistry, Direct observation, General Physics and Astronomy, Rotational spectroscopy, State (functional analysis), Physical and Theoretical Chemistry, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Scaling, Spectral line
Abstract

A weak rotationally resolved absorption band of 12 C 18 O has been identified from photographic VUV spectra and assigned to the k 3 Π ( v = 3) ← X 1 Σ + ( v = 0) forbidden transition. The experimentally determined band origin and upper state rotational constant are in close agreement to that derived from isotopic scaling. A consideration of the intensity structure of the band suggests that the band gains its intensity mainly through a k 3 Π ( v = 3)–E 1 Π ( v = 0) interaction. This is the first direct observation of the k 3 Π state for 12 C 18 O.

Published
2005
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38. Invariance of the relativistic one-particle distribution function

Author

Fabrice Debbasch, Jean-Pierre Rivet, Willem Van Leeuwen, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 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, 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), Instituut voor Theoretische fysica, Univerite d'Amsterdam, École normale supérieure - Paris (ENS-PSL), Université Nice Sophia Antipolis (1965 - 2019) (UNS), and 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)

Subjects
Statistics and Probability, Physics, Particle distribution function, Property (philosophy), Astrophysics (astro-ph), FOS: Physical sciences, Astrophysics, Lorentz covariance, 16. Peace & justice, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Theoretical physics, Distribution function, 0103 physical sciences, 05.20.Dd, 010306 general physics, PACS, 03.30.+p
Abstract

International audience; The one-particle distribution function is of importance both in non-relativistic and relativistic statistical physics. In the relativistic framework, Lorentz invariance is possibly its most fundamental property. The present article on the subject is a contrastive one: we review, discuss critically, and, when necessary, complete, the treatments found in the standard literature.

Published
2001
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39. The Rome–Paris collaboration

Author

M. Signore, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Focus (computing), Space and Planetary Science, Principal (computer security), Astronomy, Library science, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Since the first "Twinning CEE Project" between the Group of Francesco Mechiorri and our Laboratory at Observatoire de Paris and Ecole Normale Supérieure, and then through several European Networks and NASA Collaborations on the Cosmic Microwave Background, a long-term and fruitful cooperation has existed between Rome and Paris. This contribution will focus on the human story, the principal results and the possible prospects of this wonderful collaboration.

Published
2007
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40. Modeling of Planck-high frequency instrument bolometers using non-linear effects in the thermometers

Author

Adam Woodcraft, J. P. Torre, E. Bréelle, M. Piat, Alain Coulais, Warren Holmes, R. V. Sudiwala, APC - Cosmologie, AstroParticule et Cosmologie (APC (UMR_7164)), 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)-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), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université 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), PLANCK, PLANCK-HFI, 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), 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)-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), École normale supérieure - Paris (ENS-PSL), Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-AstroParticule et Cosmologie (APC (UMR_7164)), 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)-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), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-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
Nuclear and High Energy Physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Electrical field effect, Cosmic microwave background, Spider web bolometer, Field effect, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, law.invention, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 010309 optics, symbols.namesake, Optics, law, Planck HFI, 0103 physical sciences, Electron-phonon decoupling effect, Planck, 010306 general physics, Instrumentation, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Bolometer, Detector, Astrophysics::Instrumentation and Methods for Astrophysics, Decoupling (cosmology), Non-linear effects, 95.55.Jz, Thermometer, symbols, Electron–phonon decoupling effect, business
Abstract

Proceedings of the 11th International Workshop on Low Temperature Detectors - LTD-11; International audience; The Planck satellite, which is planned to be launched in 2007, is dedicated to surveying the Cosmic Microwave Background (CMB) to a high precision. Aboard this mission, the High-Frequency Instrument (HFI) will use 52 NTD Ge spiderweb bolometers made by Caltech-JPL and cooled to 100 mK by a dilution cooler. In this paper, we present a model of these detectors that includes non-linear effects seen in NTD Ge thermometers: electron-phonon decoupling and electrical field effect. We show that this model leads to consider only electrical field effect. Furthermore, the optical characterization of the HFI bolometers clearly shows a non-ideal behavior that is explained by non-linear effects in the thermometer. We finally show that these effects have to be taken into account for optimized CMB observations and to fully understand the physics of semi-conducting bolometers.

Published
2006
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41. Preface: High Energy Density Laboratory Astrophysics 2014

Author

Andrea Ciardi, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), and École normale supérieure - Paris (ENS-PSL)

Subjects
[PHYS]Physics [physics], Physics, Nuclear and High Energy Physics, Radiation, 0103 physical sciences, Energy density, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 010305 fluids & plasmas
Abstract

International audience

Published
2015
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42. A program to compute exact hydrogenic radial integrals and Einstein coefficients

Author

Hoang-Binh Dy, 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), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)

Subjects
Recurrence relation, General Physics and Astronomy, Expression (computer science), Astron, Dipole, symbols.namesake, Hardware and Architecture, Einstein coefficients, Quantum mechanics, Principal quantum number, Rydberg formula, symbols, Hypergeometric function, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mathematics
Abstract

International audience; An exact expression for the dipole radial integral of hydrogen has been given by Gordon [Ann. Phys. 2 (1929) 1031]. It contains two hypergeometric functions F(a,b;c;x), which are difficult to calculate directly, when the (negative) integers a, b are large, as in the case of high Rydberg states of hydrogenic ions. We have derived a simple method [D. Hoang-Binh, Astron. Astrophys. 238 (1990) 449], using a recurrence relation to calculate exactly F, starting from two initial values, which are very easy to compute. We present here a numerical code using this method. The code computes exact hydrogenic radial integrals, oscillator strengths, Einstein coefficients, and lifetimes, for principal quantum numbers up to 1000. Program summaryProgram title: ba5.2 Catalogue identifier: ADUU_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADUU_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1400 No. of bytes in distributed program, including test data, etc.: 11 737 Distribution format: tar.gz Programming language: Fortran 77 Computer: PC, iMac Operating system: Linux/Unix, MacOS 9.0 RAM: Less than 1 MB Classification: 2, 2.2 Catalogue identifier of previous version: ADUU_v1_0 Journal reference of previous version: Comput. Phys. Comm. 166 (2005) 191 Does the new version supersede the previous version?: Yes Nature of problem: Exact calculation of atomic data. Solution method: Use of a recurrence relation to compute hypergeometric functions. Reasons for new version: This new version computes additional important related data, namely, the total Einstein coefficients, and radiative lifetimes. Summary of revisions: Values of the total Einstein transition probability from an upper level n to a lower level n are computed, as well as the radiative lifetime of a level n. Running time: About 2 seconds

Published
2009
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43. Foreword

Author

Combes, Françoise, Melchior, Anne-Laure, 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), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Space and Planetary Science, Astronomy and Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; Not Available

Published
2004
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