Formation and abundance of primordial black holes

Primordial black holes can form in the early Universe from the collapse of cosmological perturbations after the cosmological horizon crossing. They are possible candidates for the dark matter as well as for the seeds of supermassive black holes observed today in the centre of galaxies. In calculations of spherically symmetric collapse, a Lagrangian relativistic hydrodynamical code is used to follow the non linear evolution. If the perturbation is larger than a threshold depending on the equation of state and on the specific shape of the perturbation, a black hole is formed.

Sidestepping the inversion of the weak-lensing covariance matrix with likelihood-free inference

Beyond the Standard Models with Cosmic Strings

Cosmic strings (CS) are topological defects formed after spontaneous breaking of a U(1) symmetry. Remarkably, thanks to the scaling regime, CS loops constitute a long-standing source of Gravitational Waves (GW) and produce a flat GW spectrum during radiation domination, spanning many orders of magnitude in frequency.

Gravitation Seminar: Etienne Savalle, The DAMNED experiment

The gravitation group is inviting you to the following seminar:

Exsqueez : Frequency dependent squeezing under vacuum for Virgo

Over the years gravitational waves detectors have increased their sensitivity and are now more and more limitated by the standard quantum limit.

Séminaire Gravitation - Giulia Cusin, Astrophysical background of gravitational waves: anisotropies, polarization and cross-correlations with cosmological observables.

Le groupe Gravitation organise le séminaire suivant le lundi 24 février à 11h, par Giulia Cusin, dans la salle 631B de l’APC.

Astrophysical background of gravitational waves: anisotropies, polarization and cross-correlations with cosmological observables.

Cosmology with peculiar velocities

The Universe is not homogenous. Since the early times, its structures have grown and moved under the laws of gravity. By measuring these motions today we are able to trace the spatial distribution of dark matter and accurately map the Universe. The comparison of the recovered large scale structures with the predictions of the concordance model of cosmology is then a powerful test of the laws of expansion and gravity.

The Diffuse Supernova Neutrino Background in Super-Kamiokande

Cosmology as a CFT1

Over the last decades, the emergence of conformal symmetry in gravitational systems has provided a powerful tool to investigate new aspects in classical, semi-classical and quantum general relativity.

Observational signatures of multifield inflation

Slow-roll single-field inflation constitutes the main paradigm of the
Early Universe. But this model suffers from a number of conceptual issues
that naturally lead to the consideration of multifield models of
inflation with curved field space, that have recently been under scrutiny
as realistic realizations of high-energy physics in the Early Universe.
I will show that the non-trivial internal geometry reshuffles
observational predictions from inflation, at the level of the background
(geometrical destabilisation of inflation), of linear

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Séminaire