The H0 tension and non-minimal couplings to gravity

Reconstruction of neutrino events in the MicroBooNE detector

MicroBooNE is a Liquid Argon Time Projection Chamber (LArTPC) neutrino experiment on the Booster Neutrino Beamline at the Fermi National Accelerator Laboratory, with an 85-tonne active mass.
One of MicroBooNE’s primary physics goals is to investigate the excess of electron neutrino events seen by MiniBooNE in the [200-600] MeV range.
MicroBooNE will constrain the intrinsic electron neutrino component of the beam by measuring the muon neutrino spectrum.

Séminaire Gravitation - Giulia Cusin: presentation material

This page contains the presentation material of the seminar given by Dr Giulia Cusin on the 24th of February 2020:

Astrophysical background of gravitational waves: anisotropies, polarization and cross-correlations with cosmological observables.
Available for APC members on request of the speaker.

Vainshtein screening for slowly rotating stars

We study the Vainshtein mechanism in the context of slowly rotating stars in scalar-tensor theories.
While the Vainshtein screening is well established for spherically symmetric spacetimes, we introduce a slow rotation of the source and examine its validity in the axi-symmetric case.
We solve for the frame-dragging function accounting for the slow rotation and show that the deviations from the general relativity (GR) solution are screened in the weak-field approximation, meaning the solution for the frame-dragging function is the same as GR to leading order.

TBA

The power of probe combination : cosmology with LSS and CMB data

Through weak lensing and galaxy clustering measurements, the next generation of large-scale surveys (Euclid, LSST, ...) will provide unprecedented observations and constraints on the late Universe, and thus shed light on dark matter and dark energy. On the other hand, high-quality CMB observations (current and planned) can -- and already do -- put tight constraints on the early Universe and its content.

General relativistic weak-field limit and Newtonian N-body simulations

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.

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Séminaire