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Astro Seminar

Cosmology from combining GW events with optical surveys

Speaker: Dr Will Hartley (Geneva)
Date: Wednesday 22 January 2020
Time: 14:00
Venue: Queens Buildings N/3.28

The age of gravitational wave astronomy began almost as soon as the advanced-LIGO interferometer was turned on in 2015. Four and a half years later, this new window on the cosmos has already had an impact on a wide range of topics in astronomy, and carries the potential to make a defining contribution to a number of important questions. I will discuss the electromagnetic follow-up efforts of the Dark Energy Survey GW team and the recent contribution that the combination of optical and GW astronomy has made to the problem of estimating the Hubble parameter - through using GW events as so-called standard sirens. The value of the Hubble parameter is one of the most hotly-debated topics in contemporary cosmology, and the apparent tension between values derived in the local and high-redshift universe offer the tantalising prospect of uncovering the need for new physics in our cosmological model. However, despite the excitement of the spectacular binary neutron star event of 2017, there are ongoing challenges and a great deal of hard work needed to realise the full potential of GW events for this end. I will highlight some of the current H0 results and challenges in pursuit of this goal.