Modeling Gamma-ray Bursts on the Fly (2010)

Undergraduate: Apurva Oza

Faculty Advisor: Daniel Reichart
Department: Physics & Astronomy

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Gamma-Ray Bursts (GRBs) are the farthest, most violent explosions in our Universe; they occur at great distances—billions of light years away. Our current understanding of the bursts is that they are caused by collapsing massive stars, which results in a black hole that accretes matter and produces energetic jets. GRBs tell us three pivotal things about the Universe: (1) rate at which stars formed in early Universe (2) The GRB afterglows act as backlights illuminating the gas around them and revealing the composition of the early Universe through spectroscopy; and finally (3) They tell us the re-ionization history of the Universe. It is our goal to observe these events as quickly and as fully as possible before they fade away, so that we can better probe our Universe’s infancy. We observe these bursts using robotic telescopes named PROMPT, which have the ability to capture the afterglow that is left behind in tens of seconds. GRB analysis begins with reducing and analyzing the data by using photometry techniques. The values obtained from this analysis are crucial to the next step of modeling. We discuss the process of modeling using a software called “Galapagos,” which employs models of genetic algorithms to find a best fit physical model. When we are running these fits, we are constraining two physical models—emission of light and extinction, or the absorption of the emitted light by dust. Currently we are fitting GRB 091018 to the model. We present preliminary results.