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Pierre Astier (LPNHE)22/11/2021 17:15
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Benjamin Racine (CPPM/IN2P3/CNRS), Estelle Robert (IP2I), Nicolas Regnault (LPNHE), Philippe Gris (LPC), Philippe Rosnet (Université Blaise Pascal - CNRS/IN2P3)23/11/2021 09:00
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Johan Bregeon (IN2P3 LSPC)23/11/2021 09:50
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Jérémy Neveu (IJCLab)23/11/2021 10:10
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Laurent Le Guillou (LPNHE / Sorbonne Université), Sébastien Bongard (LPNHE)23/11/2021 11:00
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Claire JURAMY ({CNRS}UMR7585), Pierre Antilogus (LPNHE), Pierre Astier (LPNHE)23/11/2021 11:20
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Sylvie Dagoret-Campagne (IJCLab)23/11/2021 12:10
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Qiufan Lin (CPPM)23/11/2021 14:30
Deep Learning models have been increasingly exploited in astrophysical studies, yet such data-driven algorithms are prone to producing biased outputs detrimental for subsequent analyses. Using galaxy photometric redshift estimation as an example, we propose a set of consecutive steps for resolving two biases in the existing Deep Learning methods, namely redshift-dependent residuals and mode...
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EMERIC LE FLOC'H (CEA)23/11/2021 14:50
Exploiting the gigantic flow of transient sky alerts uncovered by LSST will be one of the most outstanding challenges that the community of Time-Domain Astrophysics will face in the coming years. I will present a Phase-A project of a small robotic telescope operating from the Indian Ocean and that will cover 8hours ahead of Chile the fields visited by LSST every night. Reaching typical...
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Prof. Frédéric Daigne (Institut d'Astrophysique de Paris - Sorbonne Université)23/11/2021 15:10
The deep magnitude reached by the Vera Rubin-LSST combined with the very large field covered every night may allow it to play an important role in the search for electromagnetic counterparts following the detection of gravitational waves emitted by the coalescence of a binary system of two neutron stars (or of some neutron star-black hole systems): kilonova associated with the thermal emission...
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Emille Ishida (LPC-UCA)23/11/2021 15:30
The Legacy Survey of Space and Time (LSST), using the Vera Rubin Observatory LSST Camera at the Simonyi Survey Telescope, aims to survey the southern sky deeper and faster than any wide-field survey to date. Starting in 2024, and for its 10 years of operations, LSST will enable the discovery of an unprecedented large number of astrophysical transients, opening a new era of optical big data in...
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Damien TURPIN (CNES/CEA-Saclay)23/11/2021 16:00
The current decade will see the renewal of the ground and spaced based facilities that continuously
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observe the transient sky at any wavelength. In particular, in 2023, the French-Chinese mission SVOM
will pursue the multi-wavelength (messenger) study of the explosive transient sky initiated 15 years
ago by the NASA/Swift mission with a core program dedicated to the Gamma-ray Bursts (GRBs).... -
Dr Johan Bregeon (IN2P3 LSPC)23/11/2021 16:50
Gamma-ray bursts are the most violent phenomena in the universe and are characterized by a bright ultra-energetic flash of gamma rays lasting from a few seconds to several days. From constraints on the energetics, the emission that is observed at Earth has to come from a highly relativistic beam with an opening angle of just a few degrees and bulk Lorentz factor that can reach a...
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Benoit Carry (Lagrange, Observatoire de la Cote d Azur)23/11/2021 17:10
In contrast with many surveys that imaged only once their survey
footprint, the LSST will repeatedly image its survey area for a decade.
This aspect is key for Solar System science, owing to the ever-changing
coordinates and photometry of the objects imposed by celestial mechanics.The LSST is expected to revolutionize the field, by significantly
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increasing the total known... -
23/11/2021 17:30
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Dr Michel Aguena (LAPP)24/11/2021 09:00
We present here the impacts of redshift uncertainties on galaxy cluster detection using the Wavelet Z Photometric (WaZP) Cluster Finder on the DC2 Simulation. This is evaluated considering three redshift cases with different levels of complexity: true redshifts, redshifts with gaussan noise and photometric redshifts using BPZ. By comparing the clusters detected in each with the simulation...
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Calum Murray (LPSC)24/11/2021 09:20
Weak lensing magnification is an important tool in revealing the masses of galaxy clusters. Galaxies behind a cluster are magnified by the presence of the massive gravitational lens and their apparent position on the sky is deflected away from the lens centre. From such effects we can infer the mass of the lens, however such analysis may also be sensitive to the presence of intra-cluster dust,...
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Constantin Payerne (LPSC (IN2P3))24/11/2021 09:40
Cosmological analyses with galaxy cluster abundance will be significantly improved with Rubin, moving from the order of thousands of clusters to potentially hundreds of thousands clusters. A standard choice for cosmological cluster analyses is to use Poissonian likelihoods; however such a likelihood neglects the effects of sample variance whereby the anticipated number of clusters at a given...
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Raphael Gavazzi (LAM CNRS)24/11/2021 10:00
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Cécile Roucelle (APC)24/11/2021 10:50
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Morgan Schmitz (Observatoire Côte d'Azur & Université Côte d'Azur)24/11/2021 11:20
As a new addition to Rubin/LSST France, I will use this talk as an excuse to show the community some of what I have been working on, the last couple of years as a DM member, namely the handling of bright stars in the Rubin Science Pipelines. I will also talk about some of the work being carried out in the DESC working group on Point Spread Functions, for which I recently took over as co-convener.
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Mme Denise Lanzieri (Cosmostat, CEA Paris-Saclay)24/11/2021 11:40
Weak gravitational lensing is one of the most promising tools of cosmology to constrain models and probe the evolution of dark-matter structures. Yet, the current analysis techniques are only able to exploit the 2-pt statistics of the lensing signal, ignoring a large fraction of the cosmological information contained in the non-Gaussian part of the signal. Exactly how much information is lost,...
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Agnès Ferté (Jet Propulsion Laboratory)24/11/2021 12:00
I will describe the recent cosmological analysis of weak lensing and clustering data from the Dark Energy Survey 3 years of observations and show the powerful resulting constraints. I will then give my perspective on lessons learnt from this analysis and challenges for the LSST cosmological analysis of these probes, especially focusing on the issue of parameter estimation. This step is indeed...
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Philippe Gris (LPC)24/11/2021 14:00
We focus in this presentation on the impact of the parameters of a Deep Drilling (DD) strategy (number of fields, cadence of observation, filter allocation, season length, budget) on the size and depth of the Sne Ia sample observed by the survey. We present a method to collect Sne Ia complete up to higher redshifts and propose a set of realistic DD scenarios.
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Nora NICOLAS (CNRS IN2P3 IP2I)24/11/2021 14:25
The detailed nature of type Ia supernovae (SNe~Ia) remains uncertain, and as survey statistics increase, the question of astrophysical systematic uncertainties arises, notably that of the evolution of SN~Ia populations. We study the dependence on redshift of the SN~Ia \texttt{SALT2.4} light-curve stretch, which is a purely intrinsic SN property, to probe its potential redshift drift. The SN...
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Mathew Smith (IP2I/IN2P3/CNRS)24/11/2021 14:45
With measured distances to >100,000 SNeIa, LSST is the future of supernova cosmology. However, two uncertainties beyond LSST’s control will likely dominate any cosmological analysis: a nearby sample is needed to anchor the Hubble diagram, and the rate, diversity and intrinsic properties of SNeIa must be precisely measured to ensure that our understanding of dark energy is unbiased.
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The... -
Melissa Amenouche (Laboratoire de Physique de Clermont)24/11/2021 15:10
A large variety of cosmological observations has validated the $\Lambda$CDM model as the leading one in driving the dynamics of the Universe. This model requires the validity of several assumptions : the Cosmological Principle (homogeneity and isotropy at large scales). Despite numerous successes, the standard model is facing some tensions like the measurement of large scale velocity flows....
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Guy Augarde (LPNHE)24/11/2021 15:30
The Nature of Dark Energy, the mysterious component driving the acceleration of cosmic expansion, is still unknown.
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One main approach to constraint its equation of state is to construct a Hubble diagram, the evolution of luminosity distance with respect to the redshift using Type Ia Supernovae (SN Ia) used as luminosity distance indicators.
Measuring distances to SNe Ia requires a model of... -
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Frédéric Daigne (Institut d'Astrophysique de Paris - Sorbonne Université)
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EMERIC LE FLOC'H (CEA)
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