Fermi Gamma-ray Space Telescope

Search for Gamma-ray Production in Supernovae located in a dense circumstellar medium with Fermi-LAT

Anna Franckowiak
on behalf of the Fermi LAT Collaboration, Kohta Murase, Eran Ofek

Abstract:

Supernovae (SNe) exploding in a dense circumstellar medium (CSM) are predicted to accelerate cosmic rays in collisionless shocks and emit GeV gamma-rays and TeV neutrinos on a time scale of several months. We perform the first systematic search for gamma-ray emission in Fermi-LAT data from the ensemble of SNe exploding in dense CSM. We study a sample of 147 SNe Type IIn and perform a likelihood analysis for each source. In addition, we apply a stacking analysis of the closest and optically brightest sources of our sample. We do not find a significant excess in gamma-rays for any individual source nor for the stacked sources. We provide flux upper limits for individual and stacked sources. We derive a model independent limit on the gamma-ray luminosity and the ratio of gamma-ray to optical luminosity as a function of the index of the proton injection spectrum. Furthermore we present detailed flux predictions and the corresponding flux upper limit for the source SN 2010jl (PTF 10aaxf).