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08/02/2021 14:00Oral presentation
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Nicolas Oudart (LATMOS)08/02/2021 14:15
The mission of the ExoMars 2022 Martian rover, Rosalind Franklin, will be to find traces of past or present life in the shallow subsurface of Oxia Planum. To assure such traces were shielded from radiations and oxydation, the rover will be equiped with an instrumented drill, able to collect samples down to 2 m in the Martian subsurface. Samples will be analyzed in-situ, by instruments located...
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Gwenael Milcareck (LATMOS)08/02/2021 14:30
Since the end of the 1980s, observations collected by Voyager 2, large ground-based telescopes and space telescopes (notably Hubble Space Telescope) have revealed that Uranus and Neptune are cold but very active worlds. Indeed, the observations revealed intense jet streams and strong meteorological activity (dark spots or bright cloud features). It's on Neptune where we find the fastest zonal...
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Théo PELLEGRIN08/02/2021 15:00
Understanding the physical mechanism responsible for the solar wind generation is one of the key objectives of the two new solar missions, Parker Solar Probe and Solar Orbiter. The Sun produces two kinds of solar winds. The first one, the fast wind, has a velocity larger than 600 km.s-1. The second one is the slow wind which velocity is slower than 400 km.s-1. Its generation mechanism is still...
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Lami Suleiman (Laboratoire Univers et Théories)08/02/2021 15:15
The core of neutron stars involve such high densities that its matter cannot be reproduced in laboratories. There is however a chance to probe the interior of those compact stars via observation of macroscopic parameters such as the mass, the radius, the moment of inertia or the tidal deformability. We propose to give insight in the consequences of using nuclear models calculated non...
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Dr Sandrine Guerlet (LMD)08/02/2021 15:30Oral presentation
Lancé en mars 2016, et en phase opérationnelle depuis mars 2018, le satellite ExoMars Trace Gas Orbiter (TGO) embarque plusieurs spectromètres ultra performants à la recherche de gaz traces dans l'atmosphère martienne -- dont le plus emblématique est probablement le méthane. La détection passée du méthane par d'autres instruments fait l'objet de nombreuses controverses, qui ne sont toujours...
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Deborah Bardet (Laboratoire de Météorologie Dynamique)08/02/2021 16:15
Introduction: The Saturn's Semi-Annual Oscillation (SSAO) observed by Cassini is a source of debate within the community, because of its similarities (sometimes conflicting) with both the terrestrial Quasi-Biennial Oscillation (QBO) and the terrestrial Semi-Annual Oscillation (SAO). As the QBO, the downward propagation of the SSAO occurs almost to the tropopause (Schinder et al. 2011). In...
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Raphaël Duque (Institut d'Astrophysique de Paris)08/02/2021 16:30
Binary neutron star mergers offer a new and independent means of measuring the Hubble constant by combining the gravitational-wave-inferred source luminosity distance with its redshift obtained from electromagnetic follow-up. This method is limited by intrinsic degeneracy between the system distance and orbital inclination in the gravitational-wave signal. Observing the afterglow counterpart...
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M. Nam Hoang (IMCCE)08/02/2021 16:45
These astronomical signals, which have been recovered in geological records, revolutionized the accuracy and precision of the geological timescale (Gradstein & Ogg 2020). However, the orbital variations beyond 60 Myr cannot be reliably predicted because of the chaotic dynamics of the Solar System planets (Laskar 1989). Taking into account the uncertainty of the orbital evolution beyond 60 Myr...
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The AFA Team08/02/2021 17:00Oral presentation
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Mohammad Farhat (IMCCE)09/02/2021 14:00
The "timescale problem" of the Lunar origin is one of the major concerns in understanding the past history of the evolution of the Earth-Moon system. Using the present rate of tidal breaking of the Earth's rotation, a backward integration of the system places the Moon at the Roche limit just 2 billion years ago, which is not compatible with modern theories of Lunar formation. A possible...
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Simon Chiche (Institut d'Astrophysique de Paris)09/02/2021 14:15
The Giant Radio Array for Neutrino Detection (GRAND) is a project dedicated to the radio detection of ultra-high energy cosmic rays, gamma rays and neutrinos. It aims at deploying a radio array of 200 000 antennas over 200 000 km2 in mountainous regions with 20 subarrays of 10 000 antennas in several favorable locations around the world. The objective is to detect inclined (θ> 65°) particle...
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Benjamin Schneider (CEA - Saclay)09/02/2021 14:30
Long-duration gamma-ray bursts (GRBs) are produced after the death of very massive stars and can be used to trace the formation of stars inside the host galaxy. Thus, their rate might constraint the evolution of star formation throughout the cosmic times, especially at high-redshift where the trend is still under debate. However, previous works on GRB host galaxies at low redshift bring to...
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Antony DELAVOIS ({CNRS}UMR8539)09/02/2021 15:00
How Mars was during its first billion years is one of the most intriguing question in our understanding of the Solar System. The planet was host of a tremendous amount of liquid water flowing on the surface throughout the Noachian era, approximatively 4Gya. Geomorphological observations is the main evidence for liquid water since valley networks and lakes are still visible on the surface,...
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Daniela Galárraga-Espinosa (Universite Paris-Saclay)09/02/2021 15:15
Under the action of gravity, matter in the largest scales is assembled to form a gigantic network composed of nodes, filaments, walls and voids, that is called the cosmic web. According to numerical simulations, around 50% of the total mass of the Universe might reside in the cosmic filaments, thus tying our understanding of matter to that of filaments. However, since these large-scale...
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Dr Benoît Cerutti (Institut de Planétologie et d'Astrophysique de Grenoble / Université Grenoble Alpes)09/02/2021 15:30
Black hole astrophysics has taken a dramatic leap forward in recent years thanks to the detection of gravitational waves from merging stellar-mass black holes and the first image of the shadow of the supermassive black hole M87*, opening up the exciting opportunity to probe physics in curved spacetime. To this end, it is of prime importance to have an accurate description of how matter and...
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Huy Duy Do (Do)09/02/2021 16:15
For the development of future telescopes, or more generally for all heterodyne instruments, high resolution spectroscopic imaging in the THz domain is an important issue that is attracting increasing interest in many scientific fields. This canbe achieved only through the development of a mixer technology in multi-pixel configuration. Of all the existing THz mixers, the Superconducting Hot...
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Mélanie Armante (doctorate)09/02/2021 16:30
The formation of stars plays a central role in the evolution of the interstellar medium of galaxies,
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characterized by complex multi-scale mechanisms. In large hyperdense filaments generated by Galactic
collisions between molecular clouds, cloud fragments called dense cores form, then collapse, converting
their material in protostars. In order to survive this collapse and efficiently accrete... -
Claire Baskevitch09/02/2021 16:45
Galilean moons are embedded in Jupiter’s giant magnetosphere. The jovian plasma particles interact with the atmosphere of the moons, exchanging momentum and energy, and generate different phenoma such as aurora, electric current, etc..
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The exploration of the Galilean moons, and in particular Ganymede and Europa considered as potential habitats, are listed among the main objectives of the ESA... -
Alexander Vinogradov (LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris)09/02/2021 17:00
We study intermittency of turbulence in the young solar wind at 0.17 au with NASA/Parker Solar Probe during the first perihelion. We use a merged FIELDS/Search Coil and Fluxgate Magnetometers data for magnetic field, SWEAP/SPC instrument for ions and RFS/FIELDS quasi thermal noise data for electrons parameters to characterize the plasma environment. The merged magnetic waveforms have 3.4 ms...
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Ophélie MCINTOSH ({UNIV VERSAILLES ST-QUENTIN}UMR8190)10/02/2021 14:00
Mars has long been considered a planet with high astrobiological interests. Scientific research has shown that the Martian surface, due to its resemblance with Earth environments in its early history, could have seen the emergence of life. Exploratory missions, such as the one conducted by the rover Curiosity since 2012, have deployed scientific tools to find chemical and mineral evidence of...
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Fériel Tache10/02/2021 14:15
MMX (Martian Moons eXploration) is the first sample return mission from the Phobos satellite (2024) with detailed exploration of the Martian system.
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The objective is to determine the origins of the Mars’s moons in order to address the roles of small bodies in the formation of planetary systems in the habitable zone.
MMX will carry several scientific instruments, including a rover and a... -
Aline Chu (Institut d'Astrophysique de Paris)10/02/2021 14:30
Galaxy clusters are the largest gravitationally bound structures in the Universe, and are believed to form by accretion of galaxies and mergers with smaller groups of galaxies. Clusters have generally in their center a very massive galaxy (BCG, the Brightest Cluster Galaxy), which is located at the bottom of the cluster gravitational potential well, and has grown by accreting gas as well as...
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Soboh AlQeeq (LPP)10/02/2021 15:00
In July 2017, the MMS constellation was in the magnetotail with an apogee of 25 Earth radii and an average inter-satellite distance of 10 km (i.e. at electron scales). On 23 July around 16:19 UT, MMS was located at the edge of the current sheet which was in a quasi-static state. Then, MMS suddenly entered in the central plasma sheet and detected the local onset of a small substorm as indicated...
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Hiyam Debary (ONERA)10/02/2021 15:15
A new concept of imaging device has emerged during the past decade: the Segmented Planar Imaging Detector for Electro-optical Reconnaissance (SPIDER).
While with a conventional telescope the image is directly detected in the focal plane, with SPIDER, the incident wave is sampled in the pupil by a lenslet array. The wave fractions collected by each lens are then recombined in a photonic...
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Dr Frédéric Auchère (IAS)10/02/2021 15:30Oral presentation
La mission Solar Orbiter a été lancée avec succès en février 2020. Elle emporte une charge utile de 10 instruments dédiée à l'étude du Soleil et de son influence sur l'héliosphère. La phase de recette en vol s'est achevée en juin 2020. Après une première manœuvre d'assistance gravitationnelle avec Vénus en décembre, la sonde est maintenant sur une trajectoire qui l'amènera au plus près du...
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Valentin Moulay10/02/2021 16:15
Titan is one of the most promising worlds for astrobiology in our solar system. Its thick atmosphere is the site of a complex and rich chemistry that leads to the formation of a photochemical haze. This haze precipitates at the surface [1] where a wide range of reactions can occur. Titan’s surface is composed of water ice [2] which can melt under certain conditions (meteoritic impact,...
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Tony Bonnaire (Institut d'Astrophysique Spatiale)10/02/2021 16:30
In the context of recent and upcoming large-sky galaxy surveys, it is essential to automatically identify features of the Cosmic Web and, in particular, its filamentary pattern. In this presentation, we introduce T-ReX, a framework allowing the extraction of a principal graph from the observed set of galaxies, even in case noisy and heteroscedastic sampling. Based on a regularised mixture...
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Sullivan Marafico10/02/2021 16:45
The Pierre Auger Observatory is the largest cosmic-ray observatory to date. It has been built in order to study the most energetic particles in the universe, commonly known as Ultra High Energy Cosmic Rays (UHECR). With a surface of $3,000\,{\rm km^{2}}$(30 times Paris), the observatory detects cosmic rays from $10^{17.5}\text{ to }10^{20.5}\,{\rm eV}$. The energy, the shower depth ${\rm...
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Tristan Blaineau (LAL)10/02/2021 17:00
Gravitational microlensing imposes constraints on the massive compact object abundance within the Galactic halo. To estimate the effectiveness of microlensing search analysis, it is necessary to know the number of stars surveyed. However an identified source in the catalogue can be composed of several stars that could not be separated by the instrument (blending). These stars may be...
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Marion Ullmo (IAS)10/02/2021 17:15
Recently a type of neural networks called Generative Adversarial Networks (GANs) has been proposed as a solution for fast generation of simulation-like datasets, in an attempt to bypass heavy computations and expensive cosmological simulations to run in terms of time and computing power. In the present work, we build and train a GAN to look further into the strengths and limitations of such an...
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Amélie Gressier (LATMOS/IAP)11/02/2021 14:00
We present an atmospheric characterisation of two intermediate-sized planets: HD 106315 c (R$_{\rm P}$=4.98±0.23 R⊕) and HD 3167 c (R$_{\rm P}$=2.74±0.11 R⊕) whose results have been published in the ARES IV article, i.e Guilluy et al 2020. We analysed spatially scanned spectroscopic observations obtained with the G141 grism (1.125 - 1.650 μm) of the Wide Field Camera 3 (WFC3) onboard the...
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Raphaël Wicker11/02/2021 14:15
I will present the first analysis of VLT/VIMOS optical data of the two Planck detected multiple-cluster systems, PLCKG214.6+37.0 and PLCKG334.8-38.0.
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These systems were discovered in 2011 in Planck data via their Sunyaev-Zel'dovich (SZ) signal, and their nature of triple-cluster systems was revealed by XMM-Newton short observations as part of a follow-up X-ray program for validation of... -
Mehdi KOURDOURLI11/02/2021 14:30
The observation of rocky planets and older giant planets requires an attenuation of the star flux by a factor of 10^10 to 10^9. At this level of performance, active wavefront correction is critical to compensate the effects introduced by polishing quality, alignment errors, coronagraphic defects, thermal expansion, etc...
The correction requires, on the one hand, an unbiased measurement of...
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Yann Leseigneur (Institut d'Astrophysique Spatiale)11/02/2021 15:00
Dust is omnipresent within Mars’s atmosphere and at its surface. These small (micrometer-sized) particles are one of the major features of Mars modern climate and may also represent a key factor controlling some current surface properties such as composition and activity. Some dust characteristics are still imperfectly unknown, such as the link between dust storms and the seasonal dark flows...
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Samuel Zouari (APC - Université de Paris)11/02/2021 15:15
The galactic center (GC) is one of the most actively surveyed region for very high energy photons (noted VHE, over 100 GeV), by the High Energy Stereoscopic System (H.E.S.S) in our case. In addition to a diffuse emission in the central few 100 pc, one the strongest sources in the gamma ray sky, HESS J1745-290, is located at the GC, and is compatible with Sgr A*, the supermassive black hole at...
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Dr Laura Salvati (OATs-INAF / IAS)11/02/2021 15:30
In this talk I will discuss how we can infer cosmological information from the analysis of galaxy clusters. I will consider currently available data, in particular galaxy clusters detected in the mm wavelengths, and propose a forecasts analysis for future missions.
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Eduardo Vitral (Institut d’Astrophysique de Paris (UMR 7095: CNRS & Sorbonne Université), 98 bis Bd Arago, F-75014 Paris, France)11/02/2021 16:15
We analyze proper motions from the Hubble Space Telescope (HST) and the second Gaia data release along with line-of-sight velocities from the MUSE spectrograph to detect imprints of an intermediate-mass black hole (IMBH) in the center of the nearby globular cluster NGC 6397. For this, we use the new MAMPOSSt-PM Bayesian mass-modeling code, along with updated estimates of the surface density...
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Mathilde Mâlin (LESIA)11/02/2021 16:30
Direct observation is the only way to constrain the physical properties of exoplanet atmospheres. In the case of long period planets, direct imaging is challenging as it requires to achieve very high contrasts. The current generation of instruments are reaching contrast performance that allows us to observe young giant planets (still warm hence bright) that are distant from their host star (to...
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Guillaume Dréau11/02/2021 16:45
The success of the CoRoT and Kepler space-borne missions has opened a new era for stellar phys-ics. Indeed, thanks to the long four-year time series of Kepler, it is now possible to decipher in detail the oscillation spectrum of evolved giants. The information contained in these oscillation spectra, which has never been precisely studied so far for evolved red-giant branch (RGB) and...
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The SpaceBus team11/02/2021 17:00Oral presentation
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Pauline Simon (LPP)12/02/2021 14:00
Voyager 2 revealed that the solar wind ion temperature decreases (up to 40 AU) slower than what is expected from the adiabatic radial expansion model of the wind. A possible answer to this discrepancy is a local heating allowed by turbulence. Indeed, in turbulence theories energy contained at large scales cascades to smaller scales (because of the nonlinearities in the system) until it is...
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Aurélien Stcherbinine (IAS / LATMOS)12/02/2021 14:15
Mars is known to present a widespread absorption band in the 3 µm spectral range. Related to water or aqueous hydration of a mixture, it has been used in previous studies to retrieve the surface hydration of the Red Planet, using observations of the OMEGA instrument onboard Mars-Express, that has been providing a global mapping of the Martian surface in the $0.3-5.1$ µm spectral range from...
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M. Thomas Colas (IAS/APC)12/02/2021 14:30
One of the most striking predictions of the standard model of cosmology is to trace back the origin of cosmic inhomogeneities that seed the Cosmic Microwave Background anisotropies and the Large-Scale Structures of the universe to quantum fluctuations of the primordial vacuum. Yet, the quantum nature of the inhomogeneities has not been experimentally proven so far. Before thinking of an...
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Leon Vidal12/02/2021 15:00
Gravitational waves are very small variations of space-time metric which can
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be detected with high precision laser interferometry. The LISA method consist
of measuring distance fluctuations between free-falling test masses.
As with any detector, signal to noise ratio has to be optimised. In actual ground-
based interferometers like LIGO/VIRGO experiment, sensitivity is limited by
seismic... -
Yann Arribard (IAS)12/02/2021 15:15
The study of chondrites gives a lot of information about the formation and the evolution of the early solar system. The organic matter contained in those chondrites is particularly interesting. Usually, the organic matter is extracted from the meteorite matrix, what could possibly alter or modify it and inevitably make loose the information of mineral phases. To preserve this precious...
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Dr Philippe Zarka (LESIA, CNRS - Observatoire de Paris - PSL)12/02/2021 15:30
Even before the discovery of the first exoplanet in 1995, radio observations inspired by the intensity of Jupiter’s radio emissions had begun. They proved to be extremely difficult, but also motivated the development of ever larger antenna arrays. The theory rather predicts emissions at low radio frequencies and of very low intensity. But the predictions are subject to large uncertainties on...
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Gaetan GAUTHIER (LPP)12/02/2021 16:15
Recent MMS observations exploring various regions of the magnetosphere have found solitary potential structures call Electron phase-space Hole (EH). These structures have kinetic scale (dozens of Debye lengths) and persist during long time (dozens of plasma frequency periods). EH are characterized by a bipolar electric field parallel to ambient magnetic field and fastly propagate along this...
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Anne-Charlotte Perlbarg (IMCCE/IPSA)12/02/2021 16:30
Near Earth Asteroids represent a real danger for the Earth. An impact of a Potentially Hazardous Asteroid could have catastrophic consequences. The knowledge of the actual dynamic of Potential Hazardous Asteroids is essential for the purpose of an international program of planetary defense. In this respect, accurate astrometric measurements acquired over a large time span are crucial to...
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Lise RAMAMBASON (CEA/AIM)12/02/2021 16:45
Part of the ionizing continuum (Lyman continuum, LyC) produced by young stars can leak out of its host galaxy and ionize its surroundings. At high redshift, constraining the contribution of such LyC-leaking galaxies to the total ionizing budget is crucial as several studies consider primordial, low mass galaxies as the best candidates to explain the origin of reionization. Indeed, simulations...
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Valentin SAUVAGE12/02/2021 17:00
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...
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