Cosmic Explosions: The Beasts and Their Lair PDF (Adobe DRM) download by Edo Berger

Cosmic Explosions: The Beasts and Their Lair

Dissertation.Com.
Publication date: October 2005
ISBN: 9781599422336
Digital Book format: PDF (Adobe DRM)

Buy PDF

List price:
$13.00
Our price:
$11.99

You save: $1.01 (8%)
GET THIS EBOOK
FOR FREE!
Join our Facebook sweepstake, share and
get 10 likes. Winners
get notified in 24H!
The diversity of stellar death is revealed in the energy, velocity and geometry of the explosion debris ("ejecta"). Using multi-wavelength observations of gamma-ray burst (GRB) afterglows I show that GRBs, arising from the death of massive stars, are marked by relativistic, collimated ejecta ("jets") with a wide range of opening angles. I further show that the jet opening angles are strongly correlated with the isotropic-equivalent kinetic energies, such that the true relativistic energy of GRBs is nearly standard, with a value of few times 10^51 erg. A geometry-independent analysis which relies on the simple non-relativistic dynamics of GRBs at late time confirms these inferences. Still, the energy in the highest velocity ejecta, which give rise to the prompt gamma-ray emission, is highly variable. These results suggest that various cosmic explosions are powered by a common energy source, an "engine" (possibly an accreting stellar-mass black hole), with their diverse appearances determined solely by the variable high velocity output. On the other hand, using radio observations I show that local type Ibc core-collapse supernovae generally lack relativistic ejecta and are therefore not powered by engines. Instead, the highest velocity debris in these sources, typically with a velocity lower than 100,000 km/sec, are produced in the (effectively) spherical ejection of the stellar envelope. The relative rates of engine- and collapse-powered explosions suggest that the former account for only a small fraction of the stellar death rate. Motivated by the connection of GRBs to massive stars, and by their ability to overcome the biases inhenert in current galaxy surveys, I investigate the relation between GRB hosts and the underlying population of star-forming galaxies. Using the first radio and submillimeter observations of GRB hosts, I show that some are extreme starburst galaxies with the bursts directly associated with the regions of most intense star formation. I suggest, by comparison to other well-studied samples, that GRBs preferentially occur in sub-luminous, low mass galaxies, undergoing the early stages of a starburst process. If confirmed with future observations, this trend will place GRBs in the forefront of star formation and galaxy evolution studies.
Please sign in to review this product.
Format:
Devices:
Cosmic Explosions: The Beasts and Their Lair PDF (Adobe DRM) can be read on any device that can open PDF (Adobe DRM) files.

File Size:
6660 Kb
Language:
ENG
Copy From Text:
Enabled. Limit of 25 selections within 30 days.
Printing:
Enabled. Limit of 25 pages within 30 days.