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Title: Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter

Abstract

Active Galactic Nuclei (AGN) host powerful jets containing high-energy electrons and protons. The astrophysical environment where AGNs and their jets are found is characterized by large concentrations of both dark matter (DM) and intra-cluster medium (ICM) gas. As the high-energy jet particles transverse the DM and the ICM, elastic and inelastic scattering processes generically lead to the production of final-state photons. As first envisioned by Bloom and Wells (1998), and as more recently pointed out by us and others, the scattering of electrons off of DM could lead to a potentially detectable gamma-ray signal, with the parton-level contribution from protons offering dimmer perspectives. Recently, Chang et al. argued that taking into account photons from hadronization and showering, the actual photon flux is substantially increased. Here, we point out that the proton-jets have to be highly collimated, contrary to what predicted by simple blob-geometry jet-models sometimes employed in these studies, otherwise they would produce a very large flux of photons from inelaystic collisions with ICM nucleons, which would outshine by many orders of magnitude the signal from DM, for almost any reasonable ICM and DM density profiles.

Authors:
 [1];  [2];  [3]
  1. Department of Physics, University of California, 1156 High St., Santa Cruz, CA 95064 (United States)
  2. Bethe Center for Theoretical Physics and Physikalisches Institut, Universität Bonn, Bonn (Germany)
  3. Institut für Kernphysik, Universität Mainz, 55128 Mainz (Germany)
Publication Date:
OSTI Identifier:
22282994
Resource Type:
Journal Article
Journal Name:
Journal of Cosmology and Astroparticle Physics
Additional Journal Information:
Journal Volume: 2013; Journal Issue: 04; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1475-7516
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTROPHYSICS; CONCENTRATION RATIO; COSMIC PHOTONS; COSMOLOGY; DENSITY; ELECTRONS; GALAXY NUCLEI; GAMMA RADIATION; INELASTIC SCATTERING; JET MODEL; NONLUMINOUS MATTER; POTENTIALS; PROTONS

Citation Formats

Profumo, Stefano, Ubaldi, Lorenzo, and Gorchtein, Mikhail. Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter. United States: N. p., 2013. Web. doi:10.1088/1475-7516/2013/04/012.
Profumo, Stefano, Ubaldi, Lorenzo, & Gorchtein, Mikhail. Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter. United States. https://doi.org/10.1088/1475-7516/2013/04/012
Profumo, Stefano, Ubaldi, Lorenzo, and Gorchtein, Mikhail. 2013. "Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter". United States. https://doi.org/10.1088/1475-7516/2013/04/012.
@article{osti_22282994,
title = {Gamma rays from cosmic-ray proton scattering in AGN jets: the intra-cluster gas vastly outshines dark matter},
author = {Profumo, Stefano and Ubaldi, Lorenzo and Gorchtein, Mikhail},
abstractNote = {Active Galactic Nuclei (AGN) host powerful jets containing high-energy electrons and protons. The astrophysical environment where AGNs and their jets are found is characterized by large concentrations of both dark matter (DM) and intra-cluster medium (ICM) gas. As the high-energy jet particles transverse the DM and the ICM, elastic and inelastic scattering processes generically lead to the production of final-state photons. As first envisioned by Bloom and Wells (1998), and as more recently pointed out by us and others, the scattering of electrons off of DM could lead to a potentially detectable gamma-ray signal, with the parton-level contribution from protons offering dimmer perspectives. Recently, Chang et al. argued that taking into account photons from hadronization and showering, the actual photon flux is substantially increased. Here, we point out that the proton-jets have to be highly collimated, contrary to what predicted by simple blob-geometry jet-models sometimes employed in these studies, otherwise they would produce a very large flux of photons from inelaystic collisions with ICM nucleons, which would outshine by many orders of magnitude the signal from DM, for almost any reasonable ICM and DM density profiles.},
doi = {10.1088/1475-7516/2013/04/012},
url = {https://www.osti.gov/biblio/22282994}, journal = {Journal of Cosmology and Astroparticle Physics},
issn = {1475-7516},
number = 04,
volume = 2013,
place = {United States},
year = {Mon Apr 01 00:00:00 EDT 2013},
month = {Mon Apr 01 00:00:00 EDT 2013}
}