The Physics department colloquia are usually on Friday afternoons at 3 pm in Room 135. Coffee and cookies are served at 2:45 pm in the same room. Anyone is welcome.

Measuring the Neutron-Star Equation of State Using Advanced Gravitational-Wave Detectors
Leslie E. Wade, PhD Candidate, UWM Dept. of Physics

It is widely anticipated that the first direct detections of gravitational waves will be made by advanced gravitational-wave detectors, such as the two Laser Interferometer Gravitational-waves Observatories (LIGO) and Virgo interferometer. Arguably the most promising source for ground-based interferometers are coalescing binary neutron stars (NSs). NSs are stellar remnants resulting from the gravitational collapse of massive stars. They are extremely dense objects whose radius is the size of Milwaukee but whose mass is roughly 1.5 times the mass of the Sun! Through the detection of a coalescing binary NS system, advanced gravitational detectors can measure certain properties of the system. In particular, they are capable of constraining the NS equation of state (EOS), which is highly unconstrained at present. Much like how the Ideal Gas Law is an EOS relating state variables of an ideal gas, the NS EOS is a relationship that relates state variables of a NS. For instance, the NS EOS can relate mass to radius and density to pressure.

In this talk, I will explain how gravitational-wave detectors can measure EOS effects in binary NS systems, and I will present a new method of directly measuring the NS EOS by estimating the parameters of a 4-piece polytropic model that matches theoretical EOS candidates to a few percent. I will finish by discussing important sources of error in EOS measurements that is the last remaining obstacle in unlocking the secrets of the NS EOS through gravitational waves.