CAREER: Populations and Systematic Uncertainties in the Era of the Advanced Gravitational-Wave Detectors

This award supports research in relativistic astrophysics and it addresses the priority areas of NSF's "Windows on the Universe" Big Idea. The detection of gravitational waves has opened new avenues to explore the universe and some of its most fascinating phenomena. When two compact objects, black holes or neutron stars, collide, they emit gravitational waves which encode the properties of their sources, for example masses and spins.

To date, more than a dozen binary black hole and 2 binary neutron star mergers have been found in the data of the NSF-funded LIGO observatories and the Virgo detector. Over the next five years, we expect to detect more than one binary black hole source per week, and roughly one binary neutron star per month. This project will enable a broad scientific exploitation of gravitational-wave data by developing methods to combine information from a large number of sources.

At the same time, it will deal with the main sources of systematic error, which might otherwise hinder astrophysical inference, limiting its usefulness for the scientific community. In addition to enabling a reliable analysis of the population of gravitational-wave sources, this project will also increase the representation of underserved communities and underrepresented minorities in STEM.

The project includes a professional development program for high school teachers which will target low-income areas and expose the teachers and their students to the main ideas behind gravitational-wave astrophysics and highlight the many transferable skills acquired with a physics degree.

Given the tens to hundreds of compact binary systems that will be detected in the next few years, their full exploitation will bear fruit on key physics and astrophysics questions. Such a wealth of detected systems, some of which at large signal-to-noise ratio, constitutes both an opportunity and a challenge. To fully exploit the available data, sophisticated data analysis algorithms and a full control of systematic errors will be needed.

The work has on two main goals: a) to develop tools to characterize the population of compact binaries while accounting for marginal sources and for the possibility that some triggers might not be of astrophysical origin and b) to quantify and mitigate the effect of an important type of systematic errors, those those arising from the calibration of the gravitational-wave detectors. The work will thus advance key questions in gravitational-wave astrophysics and help maximize the science output of LIGO and the international network of gravitational-wave detectors.

Despite some progress over the last twenty years, the fraction of bachelor physics degrees awarded to students from under-represented minorities, and in particular African Americans, is still too low. Among the many factors that might contribute to these low numbers, is the perception that a degree in physics does not open many doors to the job market.

The project includes a professional development program for high school teachers, with schools in districts with low per-pupil expenditure. The program will have two main goals: expose the teachers, and hence their students, to the main ideas behind general relativity, gravitational waves and astrophysics, and provide examples, directly from this research program, of ideas and methods that can be directly transferred from a physics degree to a job in industry.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.