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...
The current decade will see the renewal of the ground and spaced based facilities that continuously
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)....
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...
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
increasing the total known...
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...
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.
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,...
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...
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...
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.
The...
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....
