**Sabancı University Physics Seminar**

**Title:** The gravitational wave event GW150914, and towards the geometry of the Universe from observations

**Speaker: **Nigel T. Bishop, Department of Mathematics, Rhodes University, Grahamstown, South Africa

**Date/Time: **May 16, 2016 Monday at 13:40

**Place: **Sabancı University, FENS L048

**Abstract:**

This talk is in two parts:

The LIGO observations of GW150914 are reviewed, and and it is shown how this data leads to the interpretation that it represents the merger of two black holes each of mass about 30 Msun at about 400Mpc. We also review observations of a possible coincident gamma ray burst. The implications for astrophysics and fundamental physics are discussed.

In characteristic numerical relativity, coordinates are based on null cones. The formalism is important in cosmology, since data comes from observations on our past null cone. It is in principle possible to measure the initial data required to calculate an evolution into the interior of the past null cone. In the case of spherical symmetry, it is now possible to apply this process using actual observations leading to constraints on the geometry of the Universe.

The LIGO observations of GW150914 are reviewed, and and it is shown how this data leads to the interpretation that it represents the merger of two black holes each of mass about 30 Msun at about 400Mpc. We also review observations of a possible coincident gamma ray burst. The implications for astrophysics and fundamental physics are discussed.

In characteristic numerical relativity, coordinates are based on null cones. The formalism is important in cosmology, since data comes from observations on our past null cone. It is in principle possible to measure the initial data required to calculate an evolution into the interior of the past null cone. In the case of spherical symmetry, it is now possible to apply this process using actual observations leading to constraints on the geometry of the Universe.

**Speaker: **n.bishop@ru.ac.za

**Contact**: ersing@sabanciuniv.edu