UNC PHYSICS AND ASTRONOMY COLLOQUIUM
Brad Cenko, NASA GSFC
“The Relativistic Universe”
From young stellar objects in our galaxy to gamma-ray bursts from the epoch of reionization, relativistic jets appear to be a ubiquitous phenomenon in the Universe. Aside from serving as laboratories for physical regimes inaccessible on Earth, these systems play an important role in such diverse processes as star formation, supermassive black hole growth, and galaxy evolution. In this talk I will present recent efforts to conduct a cosmic census of relativistic ejecta using wide-field, high-cadence surveys in the optical (Palomar Transient Factory) and hard X-ray (Swift Gamma-Ray Burst Explorer) bandpasses. I will focus my talk on three areas: 1) the recent discovery of a class of relativistic outbursts that appear to result from the tidal disruption of a star by a central super-massive black hole (relativistic tidal disruption flares); 2) Searches for “orphan” gamma-ray burst afterglows (e.g., those whose relativistic jets are beamed away from our line of sight, or lack high-energy prompt emission altogether); and, if time, 3) Preparing for efforts to identify the electromagnetic counterparts of gravitational wave detections from the Advanced LIGO and Virgo network of detectors.