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Title: Active galactic nuclei, neutrinos, and interacting cosmic rays in NGC 253 and NGC 1068

The galaxies M82, NGC 253, NGC 1068, and NGC 4945 have been detected in γ-rays by Fermi. Previously, we developed and tested a model for cosmic-ray interactions in the starburst galaxy M82. Now, we aim to explore the differences between starburst and active galactic nucleus (AGN) environments by applying our self-consistent model to the starburst galaxy NGC 253 and the Seyfert galaxy NGC 1068. Assuming a constant cosmic-ray acceleration efficiency by supernova remnants with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations, predict the radio and γ-ray spectra, and compare with published measurements. We find that our models easily fit the observed γ-ray spectrum for NGC 253 while constraining the cosmic-ray source spectral index and acceleration efficiency. However, we encountered difficultly modeling the observed radio data and constraining the speed of the galactic wind and the magnetic field strength, unless the gas mass is less than currently preferred values. Additionally, our starburst model consistently underestimates the observed γ-ray flux and overestimates the radio flux for NGC 1068; these issues would be resolved if the AGN is the primary source of γ-rays. We discuss the implications of these results and make predictions for the neutrinomore » fluxes for both galaxies.« less
Authors:
;  [1] ;  [2] ;  [3]
  1. Department of Physics, University of Wisconsin-Madison, WI 53706 (United States)
  2. Department of Astronomy, University of Wisconsin-Madison, WI 53706 (United States)
  3. Center for Interdisciplinary Exploration and Research in Astrophysics, Northwestern University, IL 60208 (United States)
Publication Date:
OSTI Identifier:
22348253
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 780; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; COSMIC RADIATION; COSMIC RAY SOURCES; EFFICIENCY; ELECTRONS; GALAXY NUCLEI; GAMMA RADIATION; INTERACTIONS; MAGNETIC FIELDS; MASS; MILKY WAY; NEUTRINOS; POSITRONS; PROTONS; SEYFERT GALAXIES; SIMULATION; SPECTRA; SUPERNOVA REMNANTS