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. 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. 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.

Supernovae are among the most energetic phenomena in the Universe and - lated to almost all aspects of modern astrophysics including starburst gal- ies, cosmic ray acceleration, neutron star and black hole formation, nuc- osynthesis and ISM chemical enrichment, energy input to the ISM, cosmic distance scale determination, dark energy related cosmological acceleration, gamma-ray bursts, extra-solar system neutrino burst detection, gravity wave generation, and many more. Additionally, the past 15 years have been p- ticularly productive with many new results and new understanding due in particular to the closest SN in 400 years in SN 1987A in the Large M- ellanic Cloud, and the unusually bright and close SN 1993J and SN 1994I in the nearby galaxies M81 and M51, respectively. In addition, the disc- ery of the ?-ray burst GRB 980425 and its related supernova SN 1998bw, and the con?rmation of GRB 030329/SN 2003dh, tied the study of SNe and GRBs inextricably together. With the many developments since the last - jor supernova meeting in La Serena, Chile in 1997, we felt that it was an appropriate time to bring together experts and students interested in the subject for a meeting where SN and GRB properties and interrelationships could be discussed. The tenth anniversary of SN 1993J provided such an - portunity and, appropriately, the meeting was held in Spain where SN 1993J was discovered on the early morning of 28 March 1993 by a Spanish amateur astronomer, Francisco Garc ́ ?a.

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

Supernovae and gamma-ray bursts are the strongest explosions in the Universe. Observations show that, rather than being symmetrical, they are driven by strong jets of energy and other asymmetrical effects. These observations demand theories and computations that challenge the biggest computers. This volume marks the transition to a fresh paradigm in the study of stellar explosions. It highlights the burgeoning era of routine supernova polarimetry and the insights into core collapse and thermonuclear explosions. With chapters by leading scientists, the book summarises the status of a fresh perspective on stellar explosions and should be a valuable resource for graduate students and research scientists.

This conference presents invited and contributed papers by international experts devoted to explosive phenomena in cosmic settings as diverse as stellar flares, X-ray bursts, jets, novae, supernovae, hypernovae, and gamma-ray bursts. The conference considered not only the origins of explosive behavior, but also information about the host systems that the explosive phenomena might yield. For example, X-ray bursts can be used to determine structural parameters of neutron stars, and specific types of supernovae can be used as standard candles to study the deceleration of the Hubble expansion.

What happens at the end of the life of massive stars? At one time we thought all these stars followed similar evolutionary paths. However, new discoveries have shown that things are not quite that simple. This book focuses on the extreme –the most intense, brilliant and peculiar– of astronomical explosions. It features highly significant observational finds that push the frontiers of astronomy and astrophysics, particularly as before these objects were only predicted in theory. This book is for those who want the latest information and ideas about the most dramatic and unusual explosions detected by current supernova searches. It examines and explains cataclysmic and unusual events in stellar astrophysics and presents them in a non-mathematical but highly detailed way that non-professionals can understand and enjoy.

The Story Begins In The Seventh Century During The Region Of The King Harshavardhna. Bhikku Sariputta, The Head Of The Buddhist Vihar At Sthanvishwar Is A Keen Observer Of The Star-Studded Heavens. His Pet Student Rohit Witnesses A Remarkable Sight In The Sky And Rushes To His Teacher For Guidance. Sariputta Suspects That The Event Is Of Such Great Significance That He Immediately Reports It To The King. At The KingýS Behest With RohitýS Help Sariputta Prepares Meticulous Records Of The Event Which The Buried Underground For Posterity. It Is In The Twentieth Century That The Records In The Form Of Brass Plates Are Accidentally Unearthed. Tatyasaheb Bhagvat, A Scholar On Ancient Indian Studies And The Astrophysicist Avinash Nene Together Find Might Have Momentus Implications For The Earth And Its Inhabitants. Did The Event Records By Sariputta Spell Doom? The Final Part Of The Novel Tells Us What Happened Several More Centuries Later...