Broadband Radiation from Primary Electrons in Very Energetic Supernovae
arXiv:0808.1722 · doi:10.1086/592497
Abstract
A class of very energetic supernovae (hypernovae) is associated with long gamma-ray bursts, in particular with a less energetic but more frequent population of gamma-ray bursts. Hypernovae also appear to be associated with mildly relativistic jets or outflows, even in the absence of gamma-ray bursts. Here we consider radiation from charged particles accelerated in such mildly relativistic outflows with kinetic energies of ~10^{50} erg. The radiation processes of the primarily accelerated electrons considered are synchrotron radiation and inverse-Compton scattering of synchrotron photons (synchrotron self-Compton; SSC) and of supernova photons (external inverse-Compton; EIC). In the soft X-ray regime, both the SSC and EIC flux can be the dominant component, but due to their very different spectral shapes it should be easy to distinguish between them. When the fraction of the kinetic energy going into the electrons (ε_e) is large, the SSC is expected to be important; otherwise the EIC will dominate. The EIC flux is quite high, almost independently of ε_e, providing a good target for X-ray telescopes such as XMM-Newton and Chandra. In the GeV gamma-ray regime, the EIC would be the dominant radiation process and the Gamma-ray Large Area Space Telescope (GLAST) should be able to probe the value of ε_e, the spectrum of the electrons, and their maximum acceleration energy. Accelerated protons also lead to photon radiation through the secondary electrons produced by the photopion and photopair processes. We find that over a significant range of parameters the proton component is generally less prominent than the primary electron component. We discuss the prospects for the detection of the X-ray and GeV signatures of the mildly relativistic outflow of hypernovae.
7 pages, 5 figures; accepted by ApJ
References in corpus (16)
- The shock break-out of GRB 060218/SN 2006aj
- An optical supernova associated with the X-ray flash XRF 060218
- An extremely luminous X-ray outburst at the birth of a supernova
- Relativistic ejecta from XRF 060218 and the rate of cosmic explosions
- Low Luminosity Gamma-Ray Bursts as a Unique Population: Luminosity Function, Local Rate, and Beaming Factor
- High Energy Neutrinos and Cosmic-Rays from Low-Luminosity Gamma-Ray Bursts?
- GRB060218: A Relativistic Supernova Shock Breakout
- SN 2006aj and the nature of low-luminosity gamma-ray bursts
- High Energy Afterglow from Gamma-ray Bursts
- High-energy Cosmic Rays and Neutrinos from Semi-relativistic Hypernovae
- Neutrino Spectra from Low and High Luminosity Populations of Gamma Ray Bursts
- Low-Luminosity GRB 060218: A Collapsar Jet from a Neutron Star, Leaving a Magnetar as a Remnant?
- Temporal Profiles and Spectral Lags of XRF 060218
- Cosmic rays from trans-relativistic supernovae
- GLAST Prospects for Swift-Era Afterglows
- Secondary Photons from High-energy Protons Accelerated in Hypernovae