Evaluation of Hadronic Emission in Starburst Galaxies and Star-forming Galaxies

Yun-chuan Xiang, Ze-jun Jiang, Yun-yong Tang

Published 2021-05-06Version 1

In this work, we reanalyzed the 11 years of spectral data from Fermi-LAT of starburst galaxies (SBGs) and star-forming galaxies (SFGs) currently observed. We used a one-zone model provided by \textbf{NAIMA} and the hadronic origin to explain the GeV observation data of SBGs and SFGs. We found that a protonic distribution of a power-law form with an exponential cutoff can explain the spectra of most SBGs and SFGs. However, it cannot well explain the spectral hardening components from NGC 1068 and NGC 4945 in the GeV energy band. Therefore, we considered the two-zone model to well explain these phenomena. We summarized the features of various model parameters including the spectral index, cutoff energy, protonic total energy. Similar to the evolution of supernova remnants (SNRs) in the Milky Way, we estimated that the protonic acceleration limitation inside SBGs likely reach the order of 10$^{2}$ TeV by the one-zone model, close to those of SNRs in the Milky Way.