Written by Michael Coughlin

The future of gravitational-wave astronomy after the first detection

Michael Coughlin is currently a post-doctoral fellow at Harvard University with Prof. Christopher Stubbs. In September 2016, he successfully defended his physics PhD at Harvard, titled “Gravitational-wave astronomy in the LSST era”. He began researching gravitational waves with LIGO over eight years ago as a college freshman at Carleton College in Northfield, MN and it was very exciting for him to be part of LIGO’s historical confirmation in February 2016. At Harvard, he added the Large Synoptic Survey Telescope (LSST), Pan-STARRS, and ATLAS to his research areas, including designing and building a prototype calibration system, which he nicknamed “CaBumP”.

Since LIGO announced the detection of gravitational waves from binary black hole mergers in its first observing run [1-2], the most common question I have received is “What was it like to be part of such a historic scientific discovery?” The second most common question has been: “So what happens now?” The answer is a lot of stuff! Here I’ll focus on three main goals:

1. Using LIGO to detect other sources of gravitational-waves
2. Improving the gravitational-wave detectors in order to probe farther into the cosmos
3. Electromagnetic follow-up of gravitational-wave events with telescopes to get a more complete picture

What else does nature have in store for us?

The detection of gravitational waves from binary black hole mergers has been incredibly exciting, and we look forward to the detection of more such systems. Of course, there are many other sources (pulsars, supernovae, binary neutron stars, etc.) that we hope to detect as well. As a member of the group in LIGO searching for a stochastic background of gravitational waves, I am particularly interested in the processes that could create such a signal. This includes backgrounds from compact binary coalescences, pulsars, magnetars, or core-collapse supernovae. A cosmological background (such as from inflation!) could be generated by various physical processes in the early universe. In particular, with the recent discovery of binary black-hole mergers, there is a really good chance of observing a stochastic gravitational-wave background from these systems [3].

There are other sources that are likely to produce long-lived transients, including emission from rotational instabilities in proto-neutron stars and black-hole accretion disk instabilities. There is ongoing significant effort to improve Continue reading →

Written by Samantha Usman, who is currently pursuing an MPhil at Cardiff University, UK under the supervision of Prof. Stephen Fairhurst. She graduated in May 2016 with a BS in Mathematics and Physics at Syracuse University. While at Syracuse, Usman worked with Prof. Duncan Brown on improving LIGO’s sensitivity to gravitational waves from binary star systems. In her spare time, Usman trains in Brazilian jiu jitsu and Muay Thai kickboxing and enjoys walks with her Australian Shepherd, Marble.

The discovery of gravitational waves from an undergraduate’s perspective

Author Samantha Usman training for competition in Brazilian jiu jitsu.

The first time I learned LIGO might have detected a gravitational wave, I was listening in on a conference call on September 16, 2015. Two days earlier, ripples in the fabric of space from massive black holes crashing into each other at half the speed of light had passed through the Earth. The LIGO detectors picked up these faint changes in the length of space, but they pick up all sorts of extra noise that you’d never expect; how could we be sure this was really a gravitational wave?

On September 16th, I was an undergraduate starting my senior year at Syracuse University. I’d been doing LIGO research with my advisor, Prof. Duncan Brown, for almost two and a half years. Since LIGO had yet to start an observing run, my research had been focused on testing improvements to the codes that we use to search for gravitational waves. I’d been told in those two and a half years that it would take a few years to get our detectors to design sensitivity and not to expect a detection until I was well into graduate school.

So when I sat in my boss’ office listening to a colleague in Germany say he thought we’d really seen something, I rolled my eyes and muttered, “There’s no way it’s real.” I was convinced people were Continue reading →