Cosmic-ray energy densities in star-forming galaxies
1 INAF/Osservatorio Astronomico di Trieste and INFN, via G.B. Tiepolo 11, I-34143 Trieste, Italy
2 Physics & Astronomy Department, University of Bologna, via C. Ranzani 1, I-40127 Bologna, Italy
3 School of Physics & Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel and UC San Diego, USA
Published online: 23 March 2017
The energy density of cosmic ray protons in star forming galaxies can be estimated from π0-decay γ-ray emission, synchrotron radio emission, and supernova rates. To galaxies for which these methods can be applied, the three methods yield consistent energy densities ranging from Up ~ 0.1 − 1 eV cm−3 to Up ~ 102 − 103 eV cm−3 in galaxies with low to high star-formation rates, respectively.
© The Authors, published by EDP Sciences, 2017
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