Optical and Infrared Observations of Gamma-Ray Burst Afterglows

AST-0206051

Halpern, Jules P.

The successful program of discovering and characterizing the optical afterglows of

gamma-ray bursts (GRBs) using the two telescopes of the MDM Observatory will be continued and expanded to take advantage of the increased event rate and prompt positions expected from the HETE-2 and Swift space missions, and to incorporate infrared photometry. In the first year of this three-year program, target-of-opportunity observations will be continued based on approximately 6-8 bursts per year in the northern hemisphere that are located within hours by the BeppoSAX, RXTE, and/or HETE-2 satellites. In the second and third years, beginning with the year 2003 launch of Swift, the expected localization rate will increase to the point at which it will become feasible to schedule specific, coordinated observing programs on both telescopes. It will become possible for this team to make optical identifications within minutes of a GRB event, which affords the opportunity to obtain multicolor optical light curves on the MDM 1.3m telescope, and either infrared light curves or time-dependent absorption-line studies on the MDM 2.4m. The investigators will be able to respond in a prompt, coordinated way to about a dozen such localizations per year. These data will be used to study the temporal decay and spectral evolution of GRB afterglows in order to diagnose the energetics of the fireball, and to diagnose the circumstellar environments in which these explosions occur, e.g., uniform ISM, stellar wind, or superbubble.

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