Laboratoire d’Études du Rayonnement et de la Matière en Astrophysique et Atmosphères

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Interstellar Medium and Plasmas

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What processes drive the evolution of interstellar matter in the Milky Way and in other galaxies ? What roles do the turbulence, the magnetic field, the cosmic rays, and the radiation field play in this evolution ? Those fundamental questions for modern Astrophysics now appear at many spatial scales and for a great variety of environments : from the galactic scales where the diffuse gas collapse to form the precursors of new stars ; down to the scale of proto-planetary disks where the central star strongly interacts with the surrounding matter ; and even in the stars themselves where the transport mechanisms are still unknown. To study all these astronomical objects, the group « Interstellar Medium and Plasmas » of the LERMA combine theoretical works, numerical modeling, 3D simulations, and observations of interstellar environments at high spectral and angular resolutions.

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On the observational side, our group is specialized in the treatment and the analysis of the data obtained with the most advanced space and ground-based observatories. Our expertise is particularly strong in the infrared and sub-millimeter domains which reveal the emission of atoms, molecules and interstellar dust. We have therefore been deeply involved in the recent successes and findings of Herschel and Planck space observatories, which we now follow up by collecting data with the new generation of instruments (in particular, APEX, ALMA, and soon NOEMA).

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On the numerical side, the codes developed in our group are internationally renowned as state-of-the-art tools for the analysis of interstellar matter and the interpretation of observational data. Our expertise extends from the conception of 3D numerical simulations of magnetohydrodynamics, which we run using high-level computational capacities (e.g. PRACE, MesoPSL), to the development of advanced numerical models. The strength of those models, which we provide to the community through the ISM and jets platform, is to solve a great number of microphysical processes at play in the interstellar medium, with prescriptions based on the results of laboratory experiments and theoretical studies which are partly performed in our laboratory.

Select one of the following links to know more about our activities

1. Turbulence & magnetic field

2. Matter / photon interactions

3. Stellar plasmas and laboratory astrophysics

4. Prestellar cores

5. Protostars, debris & jets

6. Accretion & ejection in stars

Click here to access our publications

Séminaires à venir

Vendredi 28 février 2020, 14h00
Salle de l'atelier, Paris
Filament Paradigm and Galactic Star Formation
Shu-ichiro INUTSUKA
Nagoya University
résumé :
Recent observations have emphasized the importance of the formation and evolution of magnetized filamentary molecular clouds in the process of star formation. Theoretical and observational investigations have provided convincing evidence for the formation of molecular cloud cores by the gravitational fragmentation of filamentary molecular clouds. Thus, the mass function and rotations of molecular cloud cores should be directly related to the properties of the filamentary molecular cloud, which determines the initial size and mass distribution of a protoplanetary disk around a protostar created in a core. In this talk I explain our current understanding of the star formation processes in the Galactic disk, and summarize various processes that are required in describing the filamentary molecular clouds to understand the star formation rate/efficiency, the stellar
initial mass function, and the angular momentum distribution of protoplanetary disks in their early evolutionary phase.
Vendredi 20 mars 2020, 14h00
Salle de l'atelier, Paris
The challenges of observing the Epoch of Reionization and Cosmic Dawn
Kateyn institute
résumé :
Low-frequency observations of the redshifted 21cm line promise to open a new window onto the first billion years of cosmic history, allowing us to directly study the astrophysical processes occurring during the Epoch of Reionization (EoR) and the Cosmic Dawn (CD). This exciting goal is challenged by the difficulty of extracting the feeble 21-cm signal buried under astrophysical foregrounds orders of magnitude brighter and contaminated by numerous instrumental systematics. Several experiments such as LOFAR, MWA, HERA, and NenuFAR are currently underway aiming at statistically detecting the 21-cm brightness temperature fluctuations from the EoR and CD. While no detection is yet in sight, considerable progress has been made recently. In this talk, I will review the many challenges faced by these difficult experiments and I will share the latest development of the LOFAR Epoch of Reionization and NenuFAR Cosmic Dawn key science projects.
Vendredi 17 avril 2020, 14h00
Salle de l'atelier, Paris
Patricia TISSERA
Universidad Andres Bello, Santiago, Chili
Vendredi 24 avril 2020, 14h00
Salle de l'atelier, Paris
Philippe ANDRE
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