LERMA UMR8112

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



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Terahertz Instrumentation and Remote Sensing

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It includes research activities in three directions:
- Terahertz instrumentation for ground-based and space telescopes
- Earth remote sensing using multiple satellite observations
- data processing and virtual observations

The Instrument group at LERMA is a key international player in milllimeter to THz components and instrumentation, with active participation in space borne missions within international collaborations. Its main goal is to advance basic knowledge in THz devices, and to develop new technologies or circuit concepts in order to be able to propose some instruments as PI or as a key partner. This group has always worked at the frontier of electronics in terms of frequency and sensitivity. It is specialized in millimeter to THz heterodyne components and receivers, which provides unique insight in the physics and chemistry, in particular of the interstellar medium and the atmosphere of planets, including the Earth.

The Software Instrumental activity of this pole focuses on the modeling of the instrumentation, the processing of the data, and the development of Virtual Observation strategies. The data come both from instruments (e.g., ALMA, NOEMA, Planck, SKA) and from numerical simulations. The activity includes all the aspects and problems related to data consolidation, data storage and perpetuation, data diffusion and sharing.

The Earth and Planet Remote Sensing component revolves around the microwave to millimeter wave radiometry from satellites, for the characterization of the Earth atmosphere and surface. Different aspects are covered, including the analysis of satellite observations, the modeling of the radiative transfer, and the development of inversion methods. It is based on collaboration with the instrument group and projects couple science and instrument studies. The group works on both atmospheric and surface analysis, using microwave observations but also exploring the synergies between visible, infrared and microwave observations. We produce geophysical variables (e.g., soil moisture, inundation extent, emissivity) over long time series at a global scale, or for use by the climate and meteorological communities. We are also involved in the analysis of satellite observations of planet, using similar methodologies.

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
Florent MERTENS
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
Tba
Philippe ANDRE
CEA
 
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