Documents de présentation
Nested sampling is a crucial tool for gravitational-wave data analysis. However, it is often computationally expensive, especially for high-dimensional and complex parameter spaces. This poses a challenge for applications to LISA data analysis. It has been shown that nessai, a nested sampling algorithm that incorporates normalising flows, can accelerate gravitational-wave inference...
One of the sources which we expect to be detected by the Laser Interferometer Space Antenna (LISA) are Massive Black Hole Binaries (MBHBs). Detection for these sources should be relatively easy, since their signal to noise ratio (SNR) will be large.
Once a detection has been made, parameter estimation is typically done with Bayesian sampling methods, such as nested sampling or variations of...
The LISA space-interferometer will simultaneously acquire gravitational waves emitted from thousands of sources through three time series.
The disentanglement of these signals poses a challenging underdetermined source separation problem.
To isolate signals based on their individual signatures, we introduce a new source separation algorithm based on learning signal representations in a...
With LISA Mission being now in phase B1, its requirements have been consolidated and we are more and more able to tailor the mission, including the methods to scientifically analyse the data during operations.
Also, to fulfil one of LISA’s role as an actor in enabling multi-messenger astronomy, we need to analyse the data in a fast and reliable way in order to quickly identify important...
LISA data is expected to feature at least one significant anisotropic stochastic gravitational wave (GW) signal: a galactic foreground comprised of the GW contribution from millions of unresolved double white dwarf (DWD) binaries throughout our galaxy. However, the Milky Way itself is not the only local host of such systems. For instance, the Large Magellanic Cloud (LMC) is expected to contain...
Observational constraints and prospects for detection of features, i.e. physically motivated oscillations in the primordial power spectrum, have so far concentrated on the CMB and Large Scale Structure surveys. Probing these features could, for instance, establish the existence of heavy particles beyond the reach of terrestrial experiments, and even test the inflationary paradigm or point to...
The detection of a stochastic gravitational wave background (SGWB) by LISA is an exciting prospect, especially in the light of the recent NANOGrav results. One of the many possible sources of cosmological SGWB signals which could be detected by LISA is cosmic strings. An important ingredient in the calculation of this contribution is the loop power spectrum which characterizes the emission...
One of the main scientific objectives of LISA is to probe the expansion rate of the Universe. In this talk, we examine the problem of measuring cosmological parameters through gravitational wave observations using LISA standard sirens. We discuss a Bayesian framework to do cosmological parameter inference with LISA dark and bright sirens, presenting forecasts based on simulated catalogs of...
In the present work we explore how modified gravity theories affect the propagation of gravitational waves produced by the merger of binary massive black holes (MBH) and also by a stochastic background. For this purpose we developed a mock of catalogs that are expected to be observed in the operating frequency band of the Laser Interferometer Space Antenna (LISA). For this proposal we develop...
The gravitational waves emitted during the coalescence of binary black holes are an excellent probe to test the behaviour of strong gravity. We propose a new test called the merger-ringdown consistency test` that focuses on probing the imprints of the dynamics in strong-gravity around the black-holes during the plunge-merger and ringdown phase. We demonstrate the feasibility of our test on a...
Black holes are potential gateways to groundbreaking discoveries. Black hole astrophysics has undergone an observational renaissance in the past 6 years. Notably, the observation of gravitational waves has provided an exciting new window to probe as close as possible to the event horizon of observed binary black hole mergers. In this talk, I will provide an overview of the strong motivations...
Accreting binary white dwarf systems are among the sources expected to emanate gravitational waves that will be detectable by LISA. We attempt to ascertain whether the individual masses of such a binary can be determined from LISA’s measurements of the frequency and frequency time derivative of gravitational waves emanated by the binary. We present analytic expressions for the gravitational...
