2020 New Investigator Grant
Carl Rodriguez, Ph.D. Assistant Professor, Department of Physics, Carnegie Mellon University
The lives and deaths of star clusters and the gravitational waves they leave behind
On Sept. 14, 2015, the two detectors of the Laser Interferometer Gravitational-wave Observatory (LIGO) observed a 0.2 second burst of energy that forever transformed physics. Five months later, when that detection of gravitational waves from the merger of two black holes was announced, a new era of astronomy began. But even five years later, we still do not fully understand the origin of the binary black holes that LIGO saw that day (to say nothing of the 50+ detections since). Many have theorized that the two black holes were born from the collapsing components of a binary star, where the two stars orbited one another from birth. Others have suggested that perhaps the black holes formed from single stars and were later forced together through strong gravitational encounters in the cores of dense star clusters. This proposal seeks to understand the middle ground between these two ideas and understand how the gravitational pull of nearby stars can alter the standard evolutionary pathways that otherwise isolated binary stars would follow. Using specialized software designed to run on graphical processing units (the same computer units that power modern video games), we will model the dynamics of many thousand small star clusters in order to better understand the effects of neighboring stars on the binaries that may create gravitational waves. This kind of specialized approach will be critical to understanding the coming thousands of detections that LIGO is expected to make over the coming decade.