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

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Presentation of LERMA

par Elise blanchard - publié le

General presentation

The LERMA (Laboratoire d’Etudes du Rayonnement et de la Matière en Astrophysique et Atmosphères) is a joint research unit (UMR 8112) between the CNRS and 3 higher education institutions, the Paris Observatory (OP), Sorbonne University (SU) and Cergy Paris University (CYU).

Geographic diversity

LERMA is a laboratory with the particularity of being located on 4 sites in the Paris region :


  • Paris Observatory
  • Observatory of Meudon
  • Sorbonne University - UPMC
  • Cergy Paris University - Neuville site

Complex structure

The LERMA has 4 supervisory bodies : the CNRS - Ile-de-France Meudon delegation (DR5), the Paris Observatory - PSL and the institutions Sorbonne University and Cergy Paris University.

In the laboratory there are 24 researchers (including 5 emeritus and 2 under contract), 7 astronomers (including 1 emeritus), 31 teacher-researchers (including 5 emeritus), 37 engineers and technicians (including 4 under contract), 22 PhD students and 6 post-docs (number of staff on 01/10/2020).

Not all members have the same employer. Indeed there are 7 different employers within the LERMA.

Its main doctoral school is ED 127, Astronomie et Astrophysique d’Île-de-France but its students also belong to 4 other doctoral schools (ED 129, 391, 564 PIF and 417).

An organization in poles

Research at LERMA is organized into 4 thematic research clusters and 1 support cluster.

Research teams conduct programs in the fields of cosmology and galaxies, dynamics of interstellar media and stellar plasmas, molecules in the Universe and instrumentation and remote sensing.

Research teams conduct programs in the fields of cosmology and galaxies, dynamics of interstellar media and stellar plasmas, molecules in the Universe and instrumentation and remote sensing.

  • "Galaxies and Cosmology" (OP)
    - Primordial universe (inflation, cosmic microwave background, reionization)
    - Galaxy formation and evolution (high redshift galaxies, secular evolution and galaxy fusion)
    - Cluster of galaxies
    - Dark matter (cold, warm or modified gravity)
    - Active nuclei, stellar formation and feedback in galaxies (efficiency, history and stellar populations)
    - Black holes and galaxies (AGN, starburst, symbiotic growth and feedback)

To learn more about Pole 1, click here or go to the "RESEARCH" tab.

  • "Dynamics of interstellar media and stellar plasmas" (OP, SU)
    - Observational characterization of the interstellar cycle
    - Formation of stars and planets
    - Modeling of interstellar medium condensation, from diffuse gas to stars and disks
    - Chemical diagnostics of interstellar dynamics
    - Turbulence and radiative transport in (circum-)stellar plasmas

To learn more about pole 2, click here or go to the "RESEARCH" tab.

  • "Molecules in the Universe" (SU, CYU, OP)
    - Gas-surface interactions (spin, photons and ice, reactivity on cold surfaces)
    - Gas phase collisional processes
    - Theory and simulations (collisional excitation and reactivity of interstellar molecules)
    - Abnormalities in nuclear spin and isotope ratios
    - Molecular parameters for terrestrial, planetary and interstellar atmospheres
    - Molecular spectroscopy experiments (molecular spectroscopy and laser instrumentation for the environment, high-resolution VUV spectroscopy of interstellar molecules)

To learn more about pole 3, click here or go to the "RESEARCH" tab.

  • "Instrumentation and remote sensing" (OP)
    - THz components and subsystems
    - Heterodyne THz instruments (for ground-based or on-board observatories (balloons, satellites) such as Herschel/HIFI and JUICE/SWI)
    - Research and development activity (HEB and SIS mixers, Schottky diodes)
    - Characterization of clear, cloudy and rainy atmospheres
    - Characterization of the surfaces of the Earth, planets and comets
    - Data processing, archiving and enhancement

To learn more about the pole 4, click here or go to the "RESEARCH" tab.

Séminaires à venir

Vendredi 26 février 2021, 14h00
Téléconférence via Zoom,
Morphological Transformations and Quenching in Galaxies : from Simulations to Observations
LERMA-Observatoire de Paris-PSL
résumé :
The origins of the relation between galaxy structure and star formation is still debated. I will discuss recent efforts to advance in our understanding of how massive galaxies change their morphology and quench from z~3. Using several state of the art deep learning techniques, we try to link hydrodynamic cosmological simulations with observations from deep surveys to constrain the physical conditions and evolutionary tracks of galaxies.

Vendredi 5 mars 2021, 14h00
Visioconférence via Zoom,
Laboratory astrophysics studies of VUV and X-ray induced photodesorption from interstellar ice analogues
Mathieu BERTIN
résumé :
The recent advances in space and ground based telescopes (ALMA, NOEMA…) have allowed the detection of more and more molecules in the gas phase in the coldest regions of the interstellar medium - ISM (star-forming regions, protoplanetary disks…). The puzzling detection of these gaseous species, including small organic molecules, in media where the temperature is very low (~ 10-100 K), is currently a major and still open question, directly linked to the astrochemical richness. Most of the observed molecules are indeed expected to either directly form or accrete on the surface of dust grains, and cannot thermally desorb in the regions where they are detected. Their observation requires thus non-thermal desorption processes, among which the desorption induced by UV or X-ray photons – so-called photodesorption – is a promising candidate. However, its role still needs to be clarified, especially in the case of the desorption of small organics molecules for which both the quantitative yields and the underlying mechanisms are lacking.

I will present the outcomes of recent laboratory astrophysics studies base on the use of the monochromatic and tunable synchrotron radiation, dedicated to understand and quantify the photodesorption processes in both the vacuum UV (7-13,6 eV) and soft X-rays (500 – 1500 eV) energy ranges. The role played by the photon energy and of the molecular ice composition on the desorption yields will be highlighted, and a special focus will be made on the case of photodesorption of complex organics molecules.

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