The first direct detection of gravitational waves by Advanced LIGO in September 2015 has officially launched the era of gravitational-wave astronomy, bringing a plethora of new astrophysics to our doorstep. This grant supports the work of members of the LIGO Scientific Collaboration at Kenyon College. Kenyon LIGO group members have lead roles in the calibration of the Advanced LIGO (aLIGO) interferometers and the search for gravitational wave signals from large black holes. The calibration of the aLIGO detectors is the first fundamental step after data has been collected by the detector. Only after the data is calibrated can searches for gravitational wave signals begin. LIGO scientists search for a range of sources, but the most promising source is the coalescence of two compact, astrophysical objects, such as black holes and neutron stars. Historically, LIGO has performed careful searches for black hole systems with masses that range up to 100 times the mass of the Sun. Members of the Kenyon LIGO group are part of the effort to expand this search to black holes of even higher masses. These large black holes may hold key answers as to how the supermassive black holes at the centers of galaxies were formed. Additionally, the Kenyon LIGO group is exploring and improving aLIGO's ability to extract information about the matter that composes neutron stars in preparation for the first gravitational wave detection from a coalescing neutron star system. While electromagnetic signals from binary neutron star systems can provide insight into the surface of neutron stars, the detection of gravitational waves from a binary neutron star system could dig deeper and reveal secrets of the illusive neutron star matter itself. Finally, this project also supports the expansion of an existing NSF-funded outreach program at Kenyon College that targets engaging middle-school-aged audiences with exciting, hands-on science workshops. Separate workshops are held for middle school boys (LADS: Learning and Doing Science) and middle school girls (GSS: Girls Science Saturdays) several Saturdays throughout the school year.
This award supports three main efforts in the field of gravitational-wave physics. The first is related to ongoing work in the calibration of the aLIGO detectors. Specifically, Kenyon LIGO group members will not only maintain existing low-latency calibration software, which is a large task as the calibration procedure is constantly changing with upgrades to the interferometers, but they will also work towards reducing the latency of the current calibration software from around a few tens of seconds down to a few seconds. The lowest possible latency calibration is crucial for electromagnetic follow-up of gravitational wave signal candidates. The main methods that will be employed to reduce the latency of the calibration software are to reduce the complexity of the procedure, shift as much of the calibration procedure as possible into the real-time instrument computers, and improve the computational efficiency of all existing calibration software. The award also supports the development and execution of a modeled, matched-filter search for intermediate mass black hole binary (IMBHB) systems. The goal of the search is to make the first confident detection of black holes in the intermediate mass range or to provide upper limits on the existence of IMBHB systems. Existing search software is being optimized to fit the needs of a higher mass, and therefore shorter waveform, matched filter search, and the search is being developed to run in a low-latency mode during future observing runs. Finally, this grant supports the development of tools to extract information about the neutron star equation of state from a binary neutron star gravitational wave detection. Markov Chain Monte Carlo (MCMC) gravitational wave parameter estimation software is being modified to more optimally explore the neutron star equation of state parameter space, and software to allow for the use of different models of the neutron star equation of state is being developed. The first few gravitational wave detections from binary neutron star systems will be able to provide a wealth of new knowledge about neutron star matter.
