Nonlinear Effects and Magnetic Field Generation

In contrast with the situation in nonrelativistic shocks 16 , the nonlinear modification of relativistic shock does not affect the asymptotic power-law index. There are two reasons for this firstly, isotropized, accelerated particles behave like a relativistic gas with adiabatic index 4 3, so that the overall compression ratio of an ultra-relativistic shock front remains 3, even when a significant part of the overall energy and momentum flux is carried by these particles. Secondly, the...

Introduction

In the standard model of radio emission from supernovae, a blast wave is driven into an ionized, dense, slowly expanding wind. As a result, a high-energy-density shell is formed. The relativistic electrons present in this shell spiral along the magnetic field and respond for the observed radio synchrotron emission. The supernova quickly increases its radio brightness with time, due to the increasingly smaller electron column density in the line of sight. When the optical depth at cm-wavelengths...

Electron Capture During Core Collapse

The residual nuclear interaction, beyond the IPM, mixes the pf shell with the levels of the sdg shell, in particular, with the lowest orbital, g9 2. The presence of configurations were more than a neutron is promoted from the pf shell into the gg 2 orbit unblocks the GT transitions for nuclei with N > 40. In addition, during core collapse electron capture occurs at temperatures T > 0.8 MeV. A model that is a able to describe both correlations and finite temperature is then necessary for the...

Recent Studies of SN 1993J

Most of the above papers were published before year 2000, but in this section we discuss several more recent studies. Matheson et al. 39 present a series of 42 Lick and Keck low-resolution optical spectra of SN 1993J from day 3 after explosion to day 2454, as well as one Keck high-dispersion spectrum from day 383. The spectra are studied in detail by 40 . Spectra during the nebular phase, but within the first two years after explosion, exhibit small-scale structure in the emission lines of some...

The Standard Model

Supernova progenitors come in basically two flavors extended red super-giants, or compact, hot stripped stellar cores. The former are thought to be related to Type IIP SNe, while the latter are most likely related to Type Ib and Ic SNe. Type IIL, IIn and IIb SNe probably represent a decreasingly massive hydrogen envelope. It is also tempting to identify this as a sequence of increasing ZAMS mass, with the Type IIP representing the most common low mass progenitors, and the Type Ic's originating...

Properties of Hypernovae

Based on the observed objects and their interpretation, it is possible to make some generalization regarding the properties of hyperenergetic type Ic SNe and their relation to the progenitor stars. All hypernovae are highly energetic. Fig. 3 shows Ekin as a function of the main-sequence mass Mms of the progenitor star as derived from fitting the optical light curves and spectra of normal and highly energetic SNe. In a hypernova branch Ek n appears to increase with Mms, reaching values much...

Corecollapse Supernovae

Supernovae of type II, i.e. explosions of stars which show strong Balmer lines of hydrogen in their spectra, and also type Ib and Ic events, are thought to originate from the collapse of massive stars, M > 8 Mq, at the end of their quiet hydrostatic nuclear burning, and the final outcome is believed to be the birth event of (most) neutron stars, and sometimes of black holes and 7-ray bursts. If this picture is correct the energy observed in the explosion ultimately must come from the binding...

Forward Shock

Reverse shocks r Interstellar scintillation 9, E n Synchrotron self-absorption n Wide-angle jets 9 jet > 0.2 Circumburst environment ISM vs. Wind, n Non-relativistic evolution E, n, B, 9 Host galaxies Obscured Star Formation Fig. 2. A schematic radio afterglow light curve. Timescales and scalings for the temporal evolution are indicated. The list summarizes aspects of the flux evolution which are unique to the radio bands (Lorentz factor, r source size, 6 energy, E density, n jet opening...

List of Contributors

Correos 3004 18080 Granada, Spain antxon iaa.es Max-Planck-Institut f r Astrophysik Karl-Schwarzschild-Str. 1 85741 Garching, Germany maa mpa-garching.mpg.de York University Toronto, Canada bartel yorku.ca Division of Physics, Mathematics and Astronomy, 105-24 California Institute of Technology Pasadena, CA 91125, USA ejb astro.caltech.edu York University Toronto, Canada mbieten yorku.ca Space Research Institute Russian Academy of Sciencs Profsoyuznaya 84 32 Moscow 117997, Russia...

Kinematics

The kinematic problem of particle acceleration at a relativistic shock, i.e., that of finding the distribution of a collection of test particles undergoing small-angle, random, elastic (in the plasma frame) deflections in the vicinity of a discontinuity in the (relativistic) plasma velocity is well-understood. An analytic method based on an eigenvalue decomposition is available which i-1 i i i i i i i-1-1 i i i i i 11 Fig. 1. The high-energy power-law index s (upper panel) and compression ratio...

PBH Caption

The best condition for an efficient gravitational PBH capture existed at the epoch preceding the galaxy formation when the first astrophysical objects Fig. 2. Time dependence of a neutrino emission intensity measured from the moment when Mbh 0.01Mwd. Fig. 2. Time dependence of a neutrino emission intensity measured from the moment when Mbh 0.01Mwd. with masses of the order 105-106 MQ were forming 2 . A PBH capture by first solitary stars 1 looks the most promising. However except for the...

References

Science 290, 953 (2000) 2. L. Amati et al. In Gamma-Ray Bursts in the Afterglow Era, ed. by E. Costa, F. Frontera, J. Hjorth (Springer Berlin, Heidelberg, 2001) pp. 34-36 3. L. Amati et al. Astron. Astrophys. 390, 81 (2002) 4. L. Amati In Proc. of the Frascati Workshop on Multiwavelength observations of Cosmic X-ray Sources, ed. by F. Giovannelli, L. Sabau-Graziati (Chinese J. of Astron. Astrophys., in press) 5. L.A. Antonelli et al. Astrophys. J. Lett. 545, L39 (2000) 6. D....

Dark GRBs

Following the unsuccessful search for an OA for GRB 970111 9 , intensive work was conducted for GRB 000210, a burst that was followed up by CHANDRA. The fact that no OA was detected despite of deep optical searches down to R 23.5 implied to classify the event as a another dark GRB. A constant brightness optical counterpart (R 23.5, 32 ) was coincident with the 1.6 error box derived by CHANDRA 30 implying that this was the likely host galaxy. A radio transient was discovered with the VLA and...