LERMA UMR8112

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



Accueil > en > Research > Molecules in the Universe > Molecular Spectroscopy Experiments > Molecular Spectroscopy and Laser Instrumentation for Environment

Molecular Spectroscopy and Laser Instrumentation for Environment

par Jean-Hugues Fillion, Mathieu Bertin - publié le , mis à jour le

Members

Christof Janssen (Researcher - Team leader), Corinne Boursier (Ass. Prof.), Hadj Elandaloussi (Engineer), Pascal Jeseck (Engineer), Yao-Veng Té (Ass. Prof.), Thomas Zanon (Ass. Prof.), Dmitri Koshelev (PhD student).

Background

Molecules are integral building blocks of our universe and their observation in various environments allows to improve our understanding of the microscopic processes that are linked to our origin and to the conditions of life. The interaction between matter and light is one of the preferred physical phenomena to probe these molecules in their diverse forms, states and environments. To that end, suitable technologies, reliable measurements and new experiments need to be carried out and developed.

Alignement d’une cellule d’absorption à faisceaux croisés pour des mesures de précision dans l’ozone.
C. Janssen

Research Interests & Collaborations

The main interest of the SMILE team is in the understanding of *molecular and dynamical processes* that play a role in *planetary and protoplanetary atmospheres*. Using laboratory experiments or atmospheric measurements, we particularly focus on the study of *isotope ratios* and *abundances* of small molecules (such as O3, CH4, CO, CO2, aromatic compounds, etc), which tell a history of their fate and origin.

Special research topics are : oxygen isotope anomalies in O + XO reactions, ozone formation pathways in planetary atmospheres and in the laboratory, UV and high-resolution IR spectroscopy of molecules of atmospheric and astrophysical interest, multi-spectral molecular properties, precision measurements of molecular parameters, observation and climatology of terrestrial grenhouse gases by ground based remote sensing (TCCON), and monitoring of atmospheric pollutants by spectroscopic methods.

This work is largely embedded within national (GSMA, Reims ; LiPhy, Grenoble ; LPL, Villetanneuse ; LSCE, Gif-sur-Yvette) and international collaborations (U. Utrecht, Netherlands ; U Copenhagen, Denmark ; U Wuppertal, Germany ; KIT Karlsruhe, Germany ; U Bremen, Germany).

Based on unique and self developed tools for quantitative in-situ and remote sensing of molecules in the gas phase, we study these molecules that are of interest on a variety of scales in space and time and range from the origin of the solar system to processes in planetary atmospheres that influence the future climate on planet Earth.

Our main instruments and experimental methods comprise the Paris-FTS (link), the laser based MIS-TDLAS and PRESPASS instruments, as well as dedicated mass spectrometers, such as a MBMS system.

The SMILE group has recently teamed up with the TA group of the pole "Instrumentation, Mesure et Environnement" to build a transverse working group TASQ (french acronym for Atmospheric Remote Sensing and Quantitative Spectroscopy) within the regional research federation IPSL

Séminaires à venir

Vendredi 20 septembre 2019, 14h00
Atelier, Paris
Challenging a Newtonian prediction through Gaia wide binaries
Xavier HERNANDEZ
UNAM, Mexico
résumé :
Under Newtonian dynamics, the relative motion of the components of a binary star should follow a Keplerian scaling with separation. Once orientation effects and a distribution of ellipticities are accounted for, dynamical evolution can be modelled to include the effects of Galactic tides and stellar mass perturbers. This furnishes a prediction for the relative velocity between the components of a binary and their projected separation. After reviewing recent work evidencing the existence of a critical acceleration scale in Elliptical Galaxies and Globular Clusters, I will show new results showing such a phenomenology in Gaia wide binaries using the latest and most accurate astrometry available. The results are consistent with the Newtonian prediction for projected separations below 7000 AU, but inconsistent with it at larger separations, where accelerations are expected to be lower than the critical a0 value of MONDian gravity. This result challenges Newtonian gravity at low accelerations and shows clearly the appearance of gravitational anomalies of the type usually attributed to dark matter at galactic scales, now at much smaller stellar scales.


 
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