Gamma-ray emission expected from Kepler's supernova remnant
Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk, Russia e-mail: firstname.lastname@example.org
2 Max-Planck-Institut für Kernphysik, Postfach 103980, 69029 Heidelberg, Germany e-mail: Heinrich.Voelk@mpi-hd.mpg.de
Accepted: 19 January 2006
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 γ-ray spectrum expected from this SNR.
Methods.Observations of the nonthermal radio and X-ray emission spectra as well as theoretical constraints for the total supernova (SN) explosion energy Esn 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 Esn 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 γ-ray flux. Exploring the expected distance range we find that for a typical explosion energy erg the expected energy flux of TeV γ-rays varies from 2 10-11 to 10-13 erg/(cm2 s) when the distance changes from kpc to 7 kpc. In all cases the γ-ray emission is dominated by -decay γ-rays due to nuclear CRs. Therefore Kepler's SNR represents a very promising target for instruments like HESS, CANGAROO and GLAST. A non-detection of γ-rays would mean that the actual source distance is larger than 7 kpc.
Key words: cosmic rays / acceleration of particles / ISM: supernova remnants / radiation mechanisms: non-thermal / gamma rays: theory / hydrodynamics
© ESO, 2006