The effect of axion-like particles on the spectrum of the extragalactic gamma-ray background. (arXiv:2012.15513v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Liang_Y/0/1/0/all/0/1">Yun-Feng Liang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zhang_X/0/1/0/all/0/1">Xing-Fu Zhang</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cheng_J/0/1/0/all/0/1">Ji-Gui Cheng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Zeng_H/0/1/0/all/0/1">Hou-Dun Zeng</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Fan_Y/0/1/0/all/0/1">Yi-Zhong Fan</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Liang_E/0/1/0/all/0/1">En-Wei Liang</a>
Axion-like particles (ALPs) provide a feasible explanation for the observed
low TeV opacity of the Universe. If the low TeV opacity is caused by ALP, then
the $>{rm TeV}$ fluxes of unresolved extragalactic point sources will be
correspondingly enhanced, resulting in an enhancement of the observed EGB
spectrum at high energies. In this work, we for the first time investigate the
ALP effect on the EGB spectrum. Our results show that the existence of ALPs can
cause the EGB spectrum to deviate from a pure EBL absorption case. The
deviation occurs at about $sim$1 TeV and current EGB measurements by Fermi-LAT
cannot identify such an effect. The observation from forthcoming VHE
instruments like LHAASO and CTA may be useful for studying this effect. We find
that although most of the sensitive ALP parameters have been ruled out by
existing ALP results, some unrestricted parameters could be probed with the EGB
observation around 10 TeV.
Axion-like particles (ALPs) provide a feasible explanation for the observed
low TeV opacity of the Universe. If the low TeV opacity is caused by ALP, then
the $>{rm TeV}$ fluxes of unresolved extragalactic point sources will be
correspondingly enhanced, resulting in an enhancement of the observed EGB
spectrum at high energies. In this work, we for the first time investigate the
ALP effect on the EGB spectrum. Our results show that the existence of ALPs can
cause the EGB spectrum to deviate from a pure EBL absorption case. The
deviation occurs at about $sim$1 TeV and current EGB measurements by Fermi-LAT
cannot identify such an effect. The observation from forthcoming VHE
instruments like LHAASO and CTA may be useful for studying this effect. We find
that although most of the sensitive ALP parameters have been ruled out by
existing ALP results, some unrestricted parameters could be probed with the EGB
observation around 10 TeV.
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