The Many Facets of Cosmic Explosions

Alicia Soderberg

ISBN 10: 1581123779 / ISBN 13: 9781581123777

Published by Dissertation.Com Okt 2007, 2007

About this Item

Neuware - Over the past few years, long-duration gamma-ray bursts (GRBs),including the subclass of X-ray flashes (XRFs), have been revealed tobe a rare variety of Type Ibc supernova (SN Ibc). While all theseevents result from the death of massive stars, the electromagneticluminosities of GRBs and XRFs exceed those of ordinary Type Ibc SNe bymany orders of magnitude. The observed diversity of stellar deathcorresponds to large variations in the energy, velocity, and geometryof the explosion ejecta. Using multi-wavelength (radio, optical,X-ray) observations of the nearest GRBs, XRFs, and SNe Ibc, I showthat GRBs and XRFs couple at least 1048 erg to relativisticmaterial while SNe Ibc typically couple less than 1048 erg to theirfastest (albeit non-relativistic) outflows. Specifically, I find thatless than 3 percent of local SNe Ibc show any evidence for association witha GRB or XRF. Interestingly, this dichotomy is not echoed by theproperties of their optical SN emission, dominated by the radioactivedecay of Nickel-56; I find that GRBs, XRFs, and SNe Ibc showsignificant overlap in their optical peak luminosity and photosphericvelocities. Recently, I identified a new class of GRBs and XRFs thatare under-luminous in comparison with the statistical sample of GRBs.Owing to their faint high-energy emission, these sub-energetic burstsare only detectable nearby (z < 0.1) and are likely 10 times morecommon than cosmological GRBs. In comparison with local SNe Ibc andtypical GRBs/XRFs, these explosions are intermediate in terms of both volumetric rate and energetics. Yet the essential physical processthat causes a dying star to produce a GRB, XRF, or sub-energeticburst, and not just a SN, remains a crucial open question. Progressrequires a detailed understanding of ordinary SNe Ibc which will befacilitated with the launch of wide-field optical surveys in the near future.

Seller Inventory # 9781581123777

Bibliographic Details

• Title: The Many Facets of Cosmic Explosions
• Publisher: Dissertation.Com Okt 2007
• Publication Date: 2007
• Language: English
• ISBN 10: 1581123779
• ISBN 13: 9781581123777
• Binding: Taschenbuch
• Condition: Neu
• Dimensions: 246W x 189H x 15D millimeters 246 millimeters width by 189 millimeters height by 15 millimeters depth
• Weight: 525 grams

About this title

Synopsis

Over the past few years, long-duration gamma-ray bursts (GRBs), including the subclass of X-ray flashes (XRFs), have been revealed to be a rare variety of Type Ibc supernova (SN Ibc). While all these events result from the death of massive stars, the electromagnetic luminosities of GRBs and XRFs exceed those of ordinary Type Ibc SNe by many orders of magnitude. The observed diversity of stellar death corresponds to large variations in the energy, velocity, and geometry of the explosion ejecta. Using multi-wavelength (radio, optical, X-ray) observations of the nearest GRBs, XRFs, and SNe Ibc, I show that GRBs and XRFs couple at least 1048 erg to relativistic material while SNe Ibc typically couple less than 1048 erg to their fastest (albeit non-relativistic) outflows. Specifically, I find that less than 3 percent of local SNe Ibc show any evidence for association with a GRB or XRF. Interestingly, this dichotomy is not echoed by the properties of their optical SN emission, dominated by the radioactive decay of Nickel-56; I find that GRBs, XRFs, and SNe Ibc show significant overlap in their optical peak luminosity and photospheric velocities. Recently, I identified a new class of GRBs and XRFs that are under-luminous in comparison with the statistical sample of GRBs. Owing to their faint high-energy emission, these sub-energetic bursts are only detectable nearby (z