Prospect of Studying Hard X- and Gamma-Rays from Type Ia Supernovae. (arXiv:1208.2094v1 [astro-ph.HE])

Prospect of Studying Hard X- and Gamma-Rays from Type Ia Supernovae. (arXiv:1208.2094v1 [astro-ph.HE]):
We perform multi-dimensional, time-dependent radiation transfer simulations
for hard X-ray and $\gamma$-ray emissions, following radioactive decays of
$^{56}$Ni and $^{56}$Co, for two-dimensional delayed detonation models of Type
Ia supernovae (SNe Ia). The synthetic spectra and light curves are compared
with the sensitivities of current and future observatories with an exposure of
$10^6$ seconds. The non-detection of the $\gamma$-ray signal from SN 2011fe at
6.4 Mpc by SPI on board INTEGRAL places the upper limit for the mass of
$^{56}$Ni as $\lsim$1.0 M_{\odot}$ independently from observations in any
other wavelengths. Signals from the newly formed radioactive species have not
been convincingly measured yet from any SN Ia, but the future X-ray and
$\gamma$-ray missions are expected to deepen the observable horizon to provide
the high energy emission data for a significant SN Ia sample. We predict that
the hard X-ray detectors on board NuStar or ASTRO-H, launched in 2012 and to be
so in 2014, will reach to SNe Ia at $\sim$15 Mpc, i.e., one SN in a few years.
Furthermore, according to the present results, the soft $\gamma$-ray detector
on board ASTRO-H will be able to detect the 158 keV line emission up to
$\sim$25 Mpc, i.e., a few SNe Ia per year. Proposed next generation
$\gamma$-ray missions, e.g., GRIPS, could reach to SNe Ia at $\sim$20 - 35$
Mpc by MeV observations. Those would provide new diagnostics and strong
constraints on explosion models, detecting rather directly the main energy
source of supernova light.