Astronomy and Astrophysics – Astrophysics
Scientific paper
1999-12-30
Astronomy and Astrophysics
Astrophysics
LaTeX, 6 figures; accepted for publication in ApJ
Scientific paper
10.1086/308828
The inverse Compton (IC) interpretation of the excess EUV emission, that was recently reported from several clusters of galaxies, suggests that the amount of relativistic electrons in the intracluster medium is highly significant, W_e>10^{61} erg. Considering Coma as the prototype galaxy cluster of nonthermal radiation, we discuss implications of the inverse Compton origin of the excess EUV fluxes in the case of low intracluster magnetic fields of order 0.1 muG, as required for the IC interpretation of the observed excess hard X-ray flux, and in the case of high fields of order 1 muG as suggested by Faraday rotation measurements. Although for such high intracluster fields the excess hard X-rays will require an explanation other than by the IC effect, we show that the excess EUV flux can be explained by the IC emission of a `relic' population of electrons driven into the incipient intracluster medium at the epoch of starburst activity by galactic winds, and later on reenergized by adiabatic compression and/or large-scale shocks transmitted through the cluster as the consequence of more recent merger events. For high magnetic fields B > 1 muG the interpretation of the radio fluxes of Coma requires a second population of electrons injected recently. They can be explained as secondaries produced by a population of relativistic protons. We calculate the fluxes of gamma-rays to be expected in both the low and high magnetic field scenarios, and discuss possibilities to distinguish between these two principal options by future gamma-ray observations.
Atoyan Armen M.
Voelk Heinrich J.
No associations
LandOfFree
Implications of a Nonthermal Origin of the Excess EUV Emission from the Coma Cluster of Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Implications of a Nonthermal Origin of the Excess EUV Emission from the Coma Cluster of Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Implications of a Nonthermal Origin of the Excess EUV Emission from the Coma Cluster of Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-312082