Implications of axion-like particles from the Fermi-LAT and H.E.S.S. observations of PG 1553+113 and PKS 2155-304
Abstract
We investigate the axion-like particle (ALP)-photon oscillation effect in the high-energy $\gamma$ -ray spectra of PG 1553+113 and PKS 2155-304 measured by Fermi-LAT and H.E.S.S. The choice of extragalactic background light (EBL) model, which induces the attenuation effect in observed $\gamma$ -ray spectra, affects the ALP implications. For the ordinary EBL model that prefers a null hypothesis, we set constraints on the ALP-photon coupling constant at 95% C.L. as $g_{a\gamma}\lesssim 5\times 10^{-11} ~{\rm{GeV}}^{-1}$ for the ALP mass $\sim 10$ neV. We also consider the CIBER observation of the cosmic infrared radiation, which shows an excess at wavelengths of $\sim 1~\mu$ m after the substraction of foregrounds. High-energy gamma-rays from extragalactic sources at high redshifts would suffer from a more significant attenuation effect caused by this excess. In this case, we find that the ALP-photon oscillation would improve the fit to the observed spectra of PKS 2155-304 and PG 1553+113 and find a favored parameter region at 95% C.L.. * Supported by the National Key R&D Program of China (2016YFA0400200) and the National Natural Science Foundation of China (U1738209, 11851303)
- Publication:
-
Chinese Physics C
- Pub Date:
- February 2021
- DOI:
- arXiv:
- arXiv:2002.07571
- Bibcode:
- 2021ChPhC..45b5105G
- Keywords:
-
- axion-like particle;
- gamma-ray;
- extragalactic background light;
- Astrophysics - High Energy Astrophysical Phenomena;
- High Energy Physics - Phenomenology
- E-Print:
- 8 pages, 7 figures, 1 table