LIRA, a pioneer in astrophysics and instrumentation, pushes back the frontiers of knowledge
LIRA
Laboratory for Instrumentation and Research in Astrophysics
WLM, a dwarf galaxy shaped by the intergalactic medium
9 February 2026WLM is a gas-rich dwarf galaxy in our Local Group, so isolated and distant that it has never interacted with other galaxies. However, this image from the MeerKAT radio telescope reveals that WLM is interacting with a very low-density ionised medium located between galaxies, known as the intergalactic medium (IGM). As WLM moves through the IGM, the surrounding medium exerts pressure on its gas, which is then pushed out in the direction opposite to its motion, as seen in the image. This interaction also disturbs the overall dynamics of WLM’s outer regions.
Studying this phenomenon will help constrain the dark matter content of WLM and determine the density of the IGM, a component of the Universe that is notoriously difficult to observe directly.
Credits: Kolhe, Hammer, Yang et al., 2026, Astronomy & Astrophysics in press
Séminaires du pôle HPA Chemistry of the D-region during solar flares and HF absorption modelling
Séminaires du pôle Étoiles et Galaxies Revealing mixed modes in compressible hydrodynamical simulations of red giant stars
News
FIRST’s photonic lantern has just successfully completed the commissioning phase.
Johan Mazoyer has been awarded an ERC Consolidator Grant 2025 for his ECHOES project.
Presentation
LIRA, a CNRS joint research unit at Paris Observatory, is a laboratory of excellence in astrophysics and instrumentation. It studies astrophysical objects, from the Solar System to our Galaxy and beyond, through five thematic areas. Through international collaboration and instrumental innovation, it pushes back the frontiers of science and contributes to the training and dissemination of knowledge.
Our projects
MIRS on the JAXA MMX mission
The Martian Moons eXploration (MMX) mission of JAXA (Japan Aerospace Exploration Agency) is the first sample-return mission from the Phobos satellite. It also includes an exploration of the Martian system. The mission’s primary objective is to decipher the origin of Martian moons, which will provide important information on planet formation and the conditions for the emergence of water on Earth-like planets.
The MIRS (MMX InfraRed Spectrometer) instrument, developed under the leadership of LESIA (now LIRA), is an imaging spectrometer that will characterize the composition of the Martian system and help select candidate sites for sample collection.
GRAVITY+
The GRAVITY instrument, installed on the European Southern Observatory’s Very Large Telescope Interferometer (VLTI/ESO), has produced spectacular and transformative results on the supermassive black hole at the centre of the Milky Way, the active nuclei of other galaxies, proto-planetary disks around young stars and exoplanets. GRAVITY+ aims to modernise both VLTI and GRAVITY to make them ≈ 100 times more sensitive, while increasing sky coverage by a factor of ≈ 100, and contrast in the vicinity of bright objects by a factor of ≈ 10. These gains will benefit all the VLTI’s current and future instruments for the next 20 years, and will perpetuate it as a unique infrastructure in the world.
All projects
Projets en développement
Projets en exploitation
Projets passés
Contacts
Contacts
Postal address
Observatoire de Paris
5, place Jules Janssen
92195 Meudon
Phone
01 45 07 77 01
Meudon site
LIRA
Observatoire de Paris
5, place Jules Janssen
92195 MEUDON Cedex
Paris site
LIRA
Observatoire de Paris
77, Avenue Denfert-Rochereau
75014 Paris
Cergy site
LIRA - Site de Neuville II
UFR Sciences et Techniques - Département de physique
5, mail Gay Lussac
95000 Neuville-sur-Oise