Cosmic Extremes: Probing Energetic Transients with Radio Observations

Kate Alexander (CfA)
October 6, 2017 - 12:15pm

Abstract

With the advent of sensitive facilities like the Karl G. Jansky Very Large Array (VLA) and planning well underway for vastly more powerful wide-field interferometers like the Square Kilometer Array, the study of radio astrophysical transients is poised for dramatic growth. Radio observations provide a unique window into a wide variety of transient events, from gamma-ray bursts (GRBs) to supernovae to tidal disruption events (TDEs) in which a star is torn apart by a supermassive black hole. In particular, GRBs and TDEs have emerged as valuable probes of some of the most extreme physics in the Universe. In these high-energy laboratories, the longer timescale of radio emission allows for extensive followup and characterization of the event energies and the densities of surrounding material, complementing observations at other wavelengths. I will present our high-cadence broadband radio studies of GRB afterglows and TDEs undertaken with the goal of learning more about their physical properties, the physics underlying the formation and growth of relativistic jets and outflows, and the environments in which these events occur. If time permits I will also touch on planned future work, including probing the short GRB/compact-object binary merger connection via follow-up observations of gravitational wave events from Advanced LIGO/Virgo, and the opportunities afforded by joint observations with the VLA and ALMA. These insights derived from these studies will be invaluable for designing and interpreting the results from future radio transient surveys.