Gravitation

Searching for gravitational waves from space: disentangling the source confusion

 LISA (Laser Interferometer Space Antenna) is a low-frequency gravitational wave observatory (0.1 mHz - 1 Hz) to be launched by ESA in 2035. It aims to observe several populations of relativistic binary stars: the white dwarf binaries in our Galaxy, super-massive black holes in coalescence, stellar-mass black holes captured by super-massive black holes in galactic nuclei, etc. In addition, we hope to observe stochastic gravitational wave signals from the primordial Universe.

La mission LISA adoptée!

La mission spatiale LISA, menée par l’Agence Spatiale Européenne, vient d’être adoptée par le Science Program Committee de l’Agence Spatiale Européenne ! Cette décision ouvre la voie à la conception et fabrication de cette ambitieuse mission spatiale scientifique, devant décoller en 2034-2035.
 

Inferring the nuclear equation of state using binary neutron star mergers

The detection of the binary neutron star merger GW170817 demonstrated that it was possible to infer the nuclear equation of state of the neutron starts, and constrain the mass-radius relation.  This internship will used a machine learning based algorithm developed at APC to test different equation of state predictions using current 2G and future 3G gravitational wave detectors.

Compact representations to detect gravitational waves from extreme-mass ratio inspirals

Extreme mass ratio inspirals (EMRI) are one of the most exciting gravitational-wave sources the Laser Interferometer Space Antenna (LISA) will detect. They are made of compact objects evolving in the highly curved spacetime around Massive Black Holes (MBH). As such, they are exquisite probes of the strong regime of gravity. EMRIs emit gravitational-wave signals that typically feature 105 orbit cycles and can last one year in the observation window.

Experimental validation of the high precision interferometric instruments onboard LISA

The proposed thesis subject is focused on the global validation process of the instrument metrological performance. Preliminary concepts exist for the various optical metrology test benches that will be required measure the instrumental characteristics. Obviously, the full constellation cannot be tested in flight conditions on ground. The instrument validation will therefore rely on a ingenious combination of specific measurements performed on the different subsystems, as well as the results obtained with specifically designed lab experiments.

Searching for Supermassive Black Hole Binaries with Pulsar Timing Array

International Pulsar Timing Array is a consortium of four collaborations working on detecting gravitational waves (GWs) in the nano-Hz band. The analysis of the third combined dataset of radio observations from 9 worldwide telescopes will start at the end of 2023. We are searching for GWs from a population of supermassive black hole binaries (SMBHBs). The expected signal could be decomposed into two components: the stochastic signal that is the result of an incoherent superposition of thousands of weak signals and the resolvable signal(s) from particularly massive and nearby binaries.
Gravitation