From standard sirens to cosmic strings: aspects of cosmology with GWs

by Danièle Steer (APC)

Wednesday 28 Feb 2018, 13:00 → 14:00 Europe/Brussels

Cyclotron

In this talk I will discuss two aspects of cosmology with GWs. The first is the determination of the Hubble constant, representing the local expansion rate of the Universe, with the binary neutron star event GW170817. I will explain how this measurement was used to obtain both the distance to the source independently of any distance-ladder as well as its redshift.   I will also discuss how, in the future, one can hope to obtain an accuracy of the order of 1% on the Hubble constant using such ``standard sirens'', and also determine other cosmological parameters.  Then I will turn to cosmic strings, which are also sources of gravitational waves. In particular I will focus on cosmic string networks with Y-junctions, resulting in the existence of many kinks, and present very recent work on strings with currents and Y-junctions as can be expected to form in many models of Grand unification.