Gravitation

LISA a passé  avec succès une revue de faisabilité et entre  officiellement en phase de conception préliminaire.

Constraining parameters of cosmic strings with Pulsar Timing Array

Pulsar timing array (PTA) uses long-term monitoring of ultra-stable millisecond pulsars to search for gravitational wave (GW) signal in the nano-Hz band. The recently detected common red noise could potentially be a stochastic GW signal.  Such a signal could be generated by a population of supper-massive black hole binaries or by violent processes in the early Universe. We will assume that this signal was produced by a network of cosmic strings and infer their properties using observational data. 

Using quantum correlations to study black-holes: squeezing techniques for present and next generation gravitational-wave detectors

Second generation gravitational wave (GW) detectors opened era of gravitational wave astronomy with the fist GW detection in 2015 and are now approaching their design sensitivity. During the 3 past observations runs, they detected 90 GW signals produced by the merging of binary compact objects, providing a wealth of scientific results ranging from the general relativity, to astrophysics and cosmology.
 

Using quantum correlations to study black-holes: squeezing techniques for present and next generation gravitational-wave detectors

Second generation gravitational wave (GW) detectors opened era of gravitational wave astronomy with the fist GW detection in 2015 and are now approaching their design sensitivity. During the 3 past observations runs, they detected 90 GW signals produced by the merging of binary compact objects, providing a wealth of scientific results ranging from the general relativity, to astrophysics and cosmology.
 

Métrologie de haute précision et modélisation de performances instrumentales pour LISA

(English version below)

   Le projet LISA de détection des ondes gravitationnelles a été sélectionné au printemps 2017 comme mission de classe " Large " de l'Agence spatiale européenne. Cette mission repose sur la capacité à mesurer, par interférométrie laser, les fluctuations de distance entre des satellites distants de 2,5 millions de km, avec une précision au picomètre sur des échelles de temps de quelques secondes à quelques heures.
LIGO et Virgo ont rendu public leur 3ème catalogue GWTC-3 de détections, couvrant la période correspondant à la fin du troisième run d'observation dans leur configuration avancée. Les détecteurs ont observé 35 nouveaux événements d'ondes gravitationnelles entre novembre 2019 et mars 2020. Le nombre total de signaux gravitationnels détectés à ce jour par le réseau international des trois détecteurs d’ondes gravitationnelles flirte désormais avec la centaine.

La publication scientifique annonçant cette observation est co-signée par l'équipe Virgo du...

DISENTANGLING AND CHARACTERIZING ASTROPHYSICAL GRAVITATIONAL WAVE SIGNALS WITH LISA

LISA is a space-based gravitational wave (GW) observatory that is planned for launch in 2034. It consists of three satellites in the free fall in the heliocentric orbit forming an equilateral triangle. Satellites exchange the laser light forming transponding interferometry allowing to detect GWs in the mHz band.  A plethora of gravitational-wave signals from different astrophysical sources is expected to be observed by LISA. These sources include galactic white dwarf binaries, extreme mass-ratio inspirals, massive black hole binaries, etc.
Crédits: Collaboration PTA

Massive black holes binaries as probes of the Universe.

Massive black holes are located in the centre of all massive galaxies. During the encounter of galaxies those black holes pair and, after some hardening period, become sources of gravitational waves (GWs).  Binaries at the early stage of inspiral emit almost monochromatic GWs and the population of massive black hole binaries (MBHBs) is the main source for the Pulsar Timing Array (PTA).  In PTA we use radio emission from the millisecond pulsars to detect GWs in the nano-Hz frequency band.

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