Gamma-Ray Bursts: From Progenitors to Probes

Harvard University, Cambridge MA

Investigators

Abstract

This award funds work to obtain and analyze X-ray, optical, infrared, millimeter and radio wavelength observations to study the explosion properties of short-lived Gamma Ray Burst emission (GRBs). GRBs are mysterious, transient highly energetic phenomena (significantly brighter than supernova explosions) that may be caused by the merger of binaries composed of neutron stars and/or a black hole. The investigators also plan to use the GRBs from very distant sources as 'flashlights' to illuminate foreground galaxies and intergalactic medium. The measurements will be used to measure the chemical enrichment of galaxies, and to constrain models of the Epoch of Re-ionization (EoR), which plays a dominant role in cosmological models. The EoR occurred when the universe was only a few hundred million years old, and marks the transition from when the universe's gaseous component changed from mostly neutral to mostly ionized. The researchers will integrate astronomy research into undergraduate courses, train and mentor students and post-doctoral fellows, and conduct public outreach. This work will be accomplished by focusing on three main goals using a variety of telescopes, including the JVLA, CARMA, ALMA, Magellan, Chandra and Gemini. The investigators will: 1) determine the composition of the GRB ejecta (baryonic vs. magnetic) in the first few hours to days after a burst is detected; 2) measure the jet opening angles of short GRBs to determine the energy scale and rate, search for r-process powered counterparts to test models that predict that GRBs are generated from compact object binaries; and 3) use GRB emission to measure galaxy metallicities and reionization at redshifts that are inaccessible to direct observations, and to study the mass-metallicity relation at z = 2 - 5.