A search for pulsed gravitational waves associated with gamma -ray bursts using LIGO

LIGO---the Laser Interferometer Gravitational-wave Observatory---is a set of instruments designed to detect gravitational waves from astrophysical sources over a broad spectrum of frequencies. The instruments have steadily improved in sensitivity over the past several years, giving the opportunity to search for a variety of possible gravitational-wave sources. This thesis describes a search for gravitational waves which are coincident with gamma-ray bursts (GRBs) which occurred during LIGO's fourth science run (S4) in early 2005, at which time LIGO was near its design goal. GRBs are intense flashes of gamma rays from sources which are likely cosmologically distant from us. These brief flashes are often trailed by decreasingly energetic electromagnetic radiation such as X-rays and visible light which can be observed by satellites or Earth-based telescopes. The energy emitted via gamma rays has been estimated as high as Eiso ∼ 1054erg (∼1 M⊙ c2), greater than any other observed source. It is possible that the progenitors of GRBs may also generate bursts of gravitational waves and may thus be observable by LIGO. Some models of the GRB progenitors predict that the associated gravitational-wave bursts (GWBs) may be divided into pulses. The search technique presented here is optimized for these types of bursts.