Gammaray emission expected from Kepler's supernova remnant
Abstract
Aims.Nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova remnants (SNRs) is used to investigate the properties of Kepler's SNR and, in particular, to predict the γray spectrum expected from this SNR.
Methods: .Observations of the nonthermal radio and Xray emission spectra as well as theoretical constraints for the total supernova (SN) explosion energy E_sn are used to constrain the astronomical and particle acceleration parameters of the system.
Results: .Under the assumption that Kepler's SN is a type Ia SN we determine for any given explosion energy E_sn and source distance d the mass density of the ambient interstellar medium (ISM) from a fit to the observed SNR size and expansion speed. This makes it possible to make predictions for the expected γray flux. Exploring the expected distance range we find that for a typical explosion energy E_sn=10^{51} erg the expected energy flux of TeV γrays varies from 2 × 10^{11} to 10^{13} erg/(cm^{2} s) when the distance changes from d=3.4 kpc to 7 kpc. In all cases the γray emission is dominated by π^0decay γrays due to nuclear CRs. Therefore Kepler's SNR represents a very promising target for instruments like HESS, CANGAROO and GLAST. A nondetection of γrays would mean that the actual source distance is larger than 7 kpc.
 Publication:

Astronomy and Astrophysics
 Pub Date:
 June 2006
 DOI:
 10.1051/00046361:20064801
 arXiv:
 arXiv:astroph/0602068
 Bibcode:
 2006A&A...452..217B
 Keywords:

 cosmic rays;
 acceleration of particles;
 ISM: supernova remnants;
 radiation mechanisms: nonthermal;
 gamma rays: theory;
 hydrodynamics;
 Astrophysics
 EPrint:
 6 pages, 4 figures. Accepted for publication in Astronomy and Astrophysics, minor typos corrected