Optical and Infrared Observations of Gamma-Ray Burst Afterglows

利用MDM天文台的两台望远镜发现和表征伽马射线暴（GRB）光学余辉的成功计划将继续进行并扩大，以利用HETE-2和Swift空间任务预期的事件率和瞬时位置的增加，并纳入红外测光。在这一为期三年的方案的第一年，将根据BeppoSAX、RXTE和/或HETE-2卫星在数小时内定位的北方半球每年约6-8次爆发，继续进行机会目标观测。在第二年和第三年，从2003年发射雨燕开始，预期的本地化率将增加到这样一个程度，即在两台望远镜上安排具体的、协调的观测计划将变得可行。该小组将有可能在伽马射线暴事件发生后几分钟内进行光学识别，这为在MDM 1.3 m望远镜上获得可见光的光变曲线以及在MDM 2.4 m望远镜上获得红外光变曲线或随时间变化的吸收线研究提供了机会。调查人员将能够以迅速、协调的方式每年对大约12起这样的本地化作出反应。这些数据将用于研究伽马射线暴余辉的时间衰减和光谱演化，以诊断火球的能量学，并诊断这些爆炸发生的星周环境，例如，均匀ISM、恒星风或超级泡沫。

AST-0206051Halpern, Jules P.The successful program of discovering and characterizing the optical afterglows ofgamma-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.***