Gamma-ray halo around 3C 279: Looking through the Sun on the 8th of October

Abstract

We discuss how the solar occultations of bright sources of energetic gamma-rays can be used to extract non-trivial physical and astrophysical information, including the angular size of the image when it is significantly smaller than the experiment's angular resolution. We analyse the EGRET data and discuss prospects for other instruments. The Fermi Gamma-ray Space Telescope will be able to constrain the size of a possible halo around 3C 279 from observations it makes on October 8 each year. © 2010 The Authors. Journal compilation © 2010 RAS.