Journal
ASTROPHYSICAL JOURNAL
Volume 757, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/757/2/183
Keywords
BL Lacertae objects: general; galaxies: active; gamma rays: general
Categories
Funding
- DOE [DE-FG03-91ER40662]
- NSF [PHY-1066293]
Ask authors/readers for more resources
Blazars are expected to produce both gamma rays and cosmic rays. Therefore, observed high-energy gamma rays from distant blazars may contain a significant contribution from secondary gamma rays produced along the line of sight by the interactions of cosmic-ray protons with background photons. Unlike the standard models of blazars that consider only the primary photons emitted at the source, models that include the cosmic-ray contribution predict that even similar to 10 TeV photons should be detectable from distant objects with redshifts as high as z >= 0.1. Secondary photons contribute to signals of point sources only if the intergalactic magnetic fields are very small, B less than or similar to 10(-14) G, and their detection can be used to set upper bounds on magnetic fields along the line of sight. Secondary gamma rays have distinct spectral and temporal features. We explore the temporal properties of such signals using a semi-analytical formalism and detailed numerical simulations, which account for all the relevant processes, including magnetic deflections. In particular, we elucidate the interplay of time delays coming from the proton deflections and from the electromagnetic cascade, and we find that, at multi-TeV energies, secondary gamma rays can show variability on timescales of years for B similar to 10(-15) G.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available