THE LMD GENERAL CIRCULATION MODELS : TOOLS FOR A BETTER
UNDERSTANDING OF ATMOSPHERIC PLANETARY PHYSICS. **A. Bierjon 1 , A. Delavois 1 , T. Pierron 1 , D. Bardet 1 , J. Naar 1 , A. Boissinot 1 , F. Forget 1 , E. Millour 1 , A. Spiga 1 , F. Hourdin 1 , T.Dubos 1 .
1 Laboratoire de Météorologie Dynamique, UMR CNRS 8539, Institut Pierre-Simon Laplace,
Sorbonne Universités, UPMC Univ Paris...
The Composite InfraRed Spectrometer (CIRS) on board Cassini revealed an equatorial oscillation of stratospheric temperature, reminiscent of the Earth’s Quasi-Biennial Oscillation (QBO), as well as anomalously high temperatures under Saturn’s rings. To better understand these predominant features of Saturn’s atmospheric circulation in the stratosphere, we have extended towards higher altitudes...
Introduction: Corroborating evidences in geomorphology and modeling has unveiled the presence of a subsurface latitude-dependent mantle (LDM) of water-ice-rich deposits down to 30° latitude in both martian hemispheres [1]. These layers appear to be less than ~ 2Myr and were possibly deposited as snowfall in response to climate change driven by shift in obliquity, similar to Earth...
Galaxy evolution from a star-forming active galaxy rich in gas, dust, and young blue stars to a passive, ‘dead’ galaxy, void of gas and filled with an old population of red stars depends mainly on the molecular gas reservoirs present inside a galaxy. Molecular gas plays an important role since it acts as a star formation fuel. Detecting and estimating the molecular gas content inside a galaxy...
The Schmidt-Kennicutt law links the star formation rate (SFR) of a galaxy or its subregions to the contained amount of gas, and remains true for a wide range of galaxies and redshifts. Understanding its origin is crucial to improve our knowledge of the star formation process. One main question is to determine which are the processes responsible of the regulation of the star formation rate,...
The rover of the ExoMars 2020 mission will be the first able to collect samples down to 2m in the Martian subsurface. To select the best drilling sites available in terms of mission safety and scientific interest, the ExoMars science team will have at their disposal the soundings of the WISDOM ground penetrating radar. The vertical resolution of those soundings is limited by the bandwidth of...
Understanding how and when galactic structures formed is a major unsolved problem in Astrophysics, yet such sources are also very red and faint, making their confirmation a challenge. Nascent galaxy overdense regions or "protoclusters" are relatively brighter at z=2-4, during which the in-situ star formation rates and/or AGN activities peaked. While obtaining spectroscopic confirmation of...
The emission lines arising from galaxies are commonly used as proxies to probe the physical and chemical state of galaxies. Spectra observed in the optical domain using ground base telescopes (ALMA, VLT) and in the infrared domain (Herschel, Spitzer, and the coming missions JWST, SPICA) provide unique “finger-prints” of the interstellar medium, in which are embedded a large set of information...
Cepheids represent a fundamental tool for measuring the distances in the Universe thanks to the Leavitt law (period-luminosity) relation. In order to calibrate this relation accurately, precise distance measurements are required. The Gaia satellite monitors a large number of Galactic Cepheids, and will eventually provide extremely accurate parallaxes to hundreds of them. This will considerably...
Solar radio bursts of Type III are believed to result from a sequence of physical processes ultimately leading to electromagnetic wave emissions near the electron plasma frequency and its second harmonic. The radiation bursts are due to energetic electron beams accelerated during solar flares. When propagating in the solar corona and the interplanetary wind, these fluxes excite Langmuir and...
Using GeMS-Gemini high angular AO-aided imaging in the near-IR, together with a radiative transfer code, we study the population of Super Stellar Clusters (SSCs) in terms of age, extinction, mass and luminosity. We detect with a fair degree of confidence 54 SSCs of mKs between 15 mag and 22 mag with a median photometric accuracy of 0.14 mag. When plotted on a color-color diagram and a...
Pluto’s tenuous atmosphere is mainly composed of molecular nitrogen N2 and methane CH4, with 515 ± 40 ppm of carbon monoxide CO (Lellouch et al., 2017, Young et al., 2018). This atmosphere is the place of a complex photochemistry producing aerosols that surround Pluto as several thin haze layers extending at more than 350 km of altitude (Cheng et al., 2017, Gladstone et al., 2016,...
The small bodies of the Solar System represent remnants of the building blocks of the planets. As such, they are our best tracers for the processes that occurred during the earliest history of the Solar System. For instance, asteroids cast light on the planetesimals composition, on the location of the snow line, on the thermal conditions of the early solar System, on planetary migration...
The X-ray light-curves of gamma-ray burst afterglows commonly feature phases of shallowly decaying or constant flux lasting from hundreds of seconds to a day, known as plateaus. Correlations exist between observable properties of the plateau and of the prompt emission for bursts with plateaus. Over the years, the origin of these plateaus has been tentatively traced to various mechanisms. These...
Since the first exoplanet detection in 1995, more than 4000 planets have been discovered. In the past tweny five years, the observations tools have greatly improved, increasing the statistics and revealing the diversity of planets. With the upcoming space telescopes such as James Webb and Ariel, detailed knowledge of exoplanet atmospheres will become possible. This opens up new challenges in...
The Mercury plasma environment is enriched in heavy ions from photo-ionization of the neutral exosphere. The time-of-flight spectrometer FIPS onboard the MESSENGER spacecraft has detected many planetary ion species, of which He$^{+}$, the Na$^{+}$-group (including Na$^{+}$, Mg$^{+}$ and Si$^{+}$) and the O$^{+}$-group (including O$^{+}$ and several water group ions) are the most abundant....
QUBIC is an experiment dedicated to the measurement of polarization B-modes of the Cosmic Microwave Background (CMB) using the novel technology of Bolometric Interferometry. Thanks to its unique spectroimaging capabilities, QUBIC will also be a powerful instrument to constrain foreground contamination. The technical demonstrator has been tested and the concept of this new instrument has been...
Q U Bolometric Interferometer for Cosmology (QUBIC) is a new ground-based experiment aiming to detect the Cosmic Microwave Background (CMB) B modes. QUBIC is based on bolometric interferometry, a new instrument architecture. This combines together the well known control of systematic effects from interferometers with the high sensitivity of bolometric detectors. It will observe the...
Interplanetary Coronal Mass Ejections (ICMEs) result from solar eruptions occurring in our star's atmosphere. These large-scale magnetised structures propagate in the interplanetary medium where they can be probed by spacecraft. Depending on their speed, ICMEs may accumulate enough solar wind plasma to form a turbulent sheath ahead of them. They therefore consist of two main substructures, a...
Ultra-long Gamma-Ray Bursts (ulGRBs) are Gamma-Ray Bursts (GRBs) with an unusually long emission in X and gamma rays, reaching durations of thousands of seconds. They could form a specific class of high-energy transient events, whose origin is still under discussion. The current sample of known ulGRBs consists of a few 10s of events which have been detected so far by the Burst Alert Telescope...
On August 17, 2017, a gravitational-wave event is detected by the LIGO and Virgo interferometers. For the first time, the signal is associated to the merger of two neutron stars. Two seconds after that, a gamma ray burst is detected by the Fermi satellite, inaugurating the multi-messenger astronomy. Many more of these events are expected to be detected in the future. The scientific results...
The Mars Orbiter Laser Altimeter (MOLA) was an instrument aboard the Mars Global Surveyor spacecraft whose first goal was to dress a precise map of Mars’ topography using laser altimetry. However, precisions of the range measurments were better than expected and allowed detection of features that could not be assigned to the surface. In particular, MOLA was the first instrument to detect polar...
Despite plenty of evidence for the existence of Dark Matter (DM), no experiment has ever managed to capture it directly. In the last decades, the Weakly Interacting Massive Particle (WIMP) paradigm, the most popular among the DM models, has proven unsuccessful experimentally in a variety of detection methods in the GeV-TeV mass range. DAMIC-M (DArk Matter In CCDs at Modane) will aim to...
Among the unexpected features revealed by MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission on the surface of Mercury, geological units named hollows are the most surprising and least understood. Possibly related to volatile components, hollows are small depressions, surrounded by bright halo, never observed on other body in our Solar System. The multispectral...
A significant number of Active Galactic Nuclei (AGN) are known to be heavily obscured: the strong UV-X emission arising from the accretion disk and the associated broad emission lines cannot be directy observed. It is now commonly accepted that this obscuration is due to a structure surrounding the central engine, called the dusty torus. This torus is known to be made of gaz and dust, to be...
Gravitational microlensing constrains massive compact object abundance within the Galactic halo. Past surveys (MACHO, EROS, OGLE, MOA) excluded objects lighter than 10 solar masses as a major component of Galactic dark matter. Recent detections of coalescences of heavier black holes by LIGO/Virgo rekindled the interest in compact objects dark matter. The efficiency of the past microlensing...
Planet-forming disks are fundamental objects thought to be inherited from large scale rotation, through the conservation of angular momentum during the collapse of a prestellar dense core. We investigate analytically and numerically the possibility for a protostellar disk to be formed from a motionless dense core which contains non-axisymmetric density fluctuations.
We show that the...
The detection of the Gravitational Wave (GW) event GW170817 emanating from the coalescence of a binary neutron star alongside an associated short gamma ray burst triggered one of the largest multi-wavelength search campaigns in history. This led to the detection of several Electromagnetic (EM) counterparts in several bands. In fact, the combination of information provided by different...
Gravitational waves from binary neutron star (BNS) coalescence, in association to short gamma-ray burst, opened a new era of multi-messenger astronomy. The identification of the counterpart and its multi-wavelength observations improved our understanding of the physics of strong-field gravity and put some constraints on astrophysical models related to matter during the merger and post-merger...
We study the possibility that a local nearby supernova Vela is responsible for the knee in the cosmic rays spectrum. This source could also explain the excess of IceCube neutrinos with energies E > 100TeV and gamma-ray excess at high Galactic latitudes at energies E > 300 GeV in FermiLat data. Our work takes into account the presence of the Local Bubble which plays the role of a shield for...
Jets and outflows are observed in a diverse range of accreting systems such as young stellar objects, galactic X-ray binaries and active galatic nuclei. The formation of jets, their propagation and their association with accretion processes are still largely unclear. However, their feedback on their immediate environment is now starting to be quantified, as their interaction with the...
FIRST (Fibered Imager foR a Single Telescope) is an original instrument dedicated to imaging substellar companions at high contrast and high angular resolution in the visible. Its principle is based on the pupile remapping technique, which turns a monolithic telescope into an interferometer. Thanks to the monomode filtering operated by the optical fibers and an appropriate beam recombination...
At present epoch, the efficiency of Mars' atmosphere sputtering by heavy ion precipitation to induce atmospheric espace is expected to be negligible under actuel solar wind conditions. It is presently difficult to directly measure its current influence on Mars atmosphere. However, it is possible to better understand the potentiel importance of this process alonf Mars' history by further...
Deflectometry is a slope acquisition metrology process for specular surfaces. The large dynamic of spatial frequency measured as well as the in-situ capabilities of deflectometry makes it a promising complementary metrology tool in the optical fabrication context.
However, systematic errors in low frequency shape reconstruction, prevent deflectometry from being an independent metrology...
The final step of the life of a massive star is its collapse and explosion creating a supernova. During the collapse phase, several phenomena happen in the core of the star before the observed explosion. One of these phenomena is the development of instabilities. The collapse creates a shock wave that becomes stationary $\sim$150 km away from the surface of the proto-neutron star (PNS). All...
The use of stable sub-Kelvin coolers is a key technology in order to reach the highest sensitivity that astrophysical space missions can offer. Historically, few instruments (e.g. Planck HFI or Hitomi SXS) required temperature down to 100 mK. Currently, two technologies can provide such temperatures in a space environment: ADR (Adiabatic Demagnetization Refrigerator) and OCDR (Open Cycled...
Water ice clouds have been observed in the Martian atmosphere since 1972, but as recent studies have shown their important role in the martian climate there is a growing need to better characterize the properties of water ice aerosols with observational constraints.
The Atmospheric Chemistry Suite (ACS) instrument onboard the ExoMars Trace Gas Orbiter (TGO) ESA-Roscosmos mission began...
