The flux of high-energy astrophysical $\gamma$ rays is attenuated by the
production of electron-positron pairs from scattering off of extragalactic
background light (EBL). We use the most up-to-date information on galaxy
populations to compute their contributions to the pair-production optical
depth. We find that the optical depth inferred from $\gamma$-ray measurements
exceeds that expected from galaxies at the $\sim2\sigma$ level. If the excess
is modeled as a frequency-independent re-scaling of the standard contribution
to the EBL from galaxies, then it is detected at the $2.7\sigma$ level (an
overall $14-30\%$ increase of the EBL). If the frequency dependence of the
excess is instead modeled as a two-photon decay of a dark-matter axion, then
the excess is favored over the null hypothesis of no excess at the $2.1\sigma$
confidence level. While we find no evidence for a dark-matter signal, the
analysis sets the strongest current bounds on the photon-axion coupling over
the $8-25$ eV mass range.
%0 Generic
%1 bernal2022seeking
%A Bernal, José Luis
%A Caputo, Andrea
%A Sato-Polito, Gabriela
%A Mirocha, Jordan
%A Kamionkowski, Marc
%D 2022
%K tifr
%T Seeking dark matter with $\gamma$-ray attenuation
%U http://arxiv.org/abs/2208.13794
%X The flux of high-energy astrophysical $\gamma$ rays is attenuated by the
production of electron-positron pairs from scattering off of extragalactic
background light (EBL). We use the most up-to-date information on galaxy
populations to compute their contributions to the pair-production optical
depth. We find that the optical depth inferred from $\gamma$-ray measurements
exceeds that expected from galaxies at the $\sim2\sigma$ level. If the excess
is modeled as a frequency-independent re-scaling of the standard contribution
to the EBL from galaxies, then it is detected at the $2.7\sigma$ level (an
overall $14-30\%$ increase of the EBL). If the frequency dependence of the
excess is instead modeled as a two-photon decay of a dark-matter axion, then
the excess is favored over the null hypothesis of no excess at the $2.1\sigma$
confidence level. While we find no evidence for a dark-matter signal, the
analysis sets the strongest current bounds on the photon-axion coupling over
the $8-25$ eV mass range.
@misc{bernal2022seeking,
abstract = {The flux of high-energy astrophysical $\gamma$ rays is attenuated by the
production of electron-positron pairs from scattering off of extragalactic
background light (EBL). We use the most up-to-date information on galaxy
populations to compute their contributions to the pair-production optical
depth. We find that the optical depth inferred from $\gamma$-ray measurements
exceeds that expected from galaxies at the $\sim2\sigma$ level. If the excess
is modeled as a frequency-independent re-scaling of the standard contribution
to the EBL from galaxies, then it is detected at the $2.7\sigma$ level (an
overall $14-30\%$ increase of the EBL). If the frequency dependence of the
excess is instead modeled as a two-photon decay of a dark-matter axion, then
the excess is favored over the null hypothesis of no excess at the $2.1\sigma$
confidence level. While we find no evidence for a dark-matter signal, the
analysis sets the strongest current bounds on the photon-axion coupling over
the $8-25$ eV mass range.},
added-at = {2022-08-31T09:53:52.000+0200},
author = {Bernal, José Luis and Caputo, Andrea and Sato-Polito, Gabriela and Mirocha, Jordan and Kamionkowski, Marc},
biburl = {https://www.bibsonomy.org/bibtex/2a2b02c2e0b2fe43816b6ba2126198adb/citekhatri},
description = {Seeking dark matter with $\gamma$-ray attenuation},
interhash = {057367515c002a9e63c1c66ad5217edc},
intrahash = {a2b02c2e0b2fe43816b6ba2126198adb},
keywords = {tifr},
note = {cite arxiv:2208.13794Comment: 5 pages (+4 pages of references), 3 figures. 3 pages and 3 figures of supplementary material},
timestamp = {2022-08-31T09:53:52.000+0200},
title = {Seeking dark matter with $\gamma$-ray attenuation},
url = {http://arxiv.org/abs/2208.13794},
year = 2022
}