Analysis and interpretation of gamma-ray burst continuum spectral evolution with BATSE data

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dc.contributor.advisorLiang, Edison P.en_US
dc.creatorCrider, Anthony Wayneen_US
dc.date.accessioned2009-06-04T08:04:50Zen_US
dc.date.available2009-06-04T08:04:50Zen_US
dc.date.issued1999en_US
dc.description.abstractOnce a day, a flash of gamma-rays erupts somewhere in space and is detected by an international fleet of satellites. Since their first detection over a quarter century ago, these gamma-ray bursts have puzzled researchers who could not determine their distance, emission mechanism, or progenitor. Much of this confusion arose as theorists attempted to create a single model to explain what we now believe are at least two, and probably more, populations of gamma-ray transients. Within the past two years, thanks largely to the Dutch-Italian satellite BeppoSAX, astronomers discovered that bursts have multiwavelength fading afterglows. This helped them determine that most gamma-ray bursts are from distant galaxies. However, it did not answer the questions regarding the emission mechanism or the progenitor. We place constraints on the emission mechanism by closely examining the spectral evolution of gamma-ray bursts observed by the American instrument BATSE. From a sample of 41 distinct pulses in 26 bright gamma-ray bursts, we have determined that the pulses appear to be radiatively cooling. We also studied the evolving spectral shape in 79 bursts. In particular, we found that both the range and evolution of the spectral index below the spectral break conflict with the predictions of a popular synchrotron shock model. They instead suggest inverse Comptonization in a hybrid thermal plus nonthermal plasma as the emission mechanism. With our Monte Carlo codes, we have begun the generation of a library of inverse Compton spectra. Using them, we have made preliminary fits to two bursts with prompt multiwavelength data. The characteristic "terrace-shaped" Compton spectrum is evident in both using BATSE data alone. This shape appears to be confirmed for the January 1, 1997 burst using BeppoSAX X-ray data and for the January 23, 1999 burst using optical data from the ground-based robotic telescope, ROTSE. Both bursts appear to be enshrouded in a material with a high initial Thomson scattering depth tT≳20 . Fitting with a larger, more organized library of Monte Carlo simulations will be required before precise limits can be placed on physical parameters such as the energies, masses, and densities of bursters.en_US
dc.format.extent105 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoTHESIS SP. SCI. 1999 CRIDER, A.en_US
dc.identifier.citationCrider, Anthony Wayne. "Analysis and interpretation of gamma-ray burst continuum spectral evolution with BATSE data." (1999) Diss., Rice University. <a href="https://hdl.handle.net/1911/19367">https://hdl.handle.net/1911/19367</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/19367en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectStatisticsen_US
dc.subjectAtmospheric sciencesen_US
dc.subjectRadiationen_US
dc.titleAnalysis and interpretation of gamma-ray burst continuum spectral evolution with BATSE dataen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentSpace Scienceen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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