Search for line signal candidates in the Fermi-LAT data

TL;DR

This study analyzed the entire sky using Fermi-LAT data to search for gamma-ray line signals, finding no significant evidence and setting constraints on dark matter annihilation cross sections.

Contribution

It provides a comprehensive search for gamma-ray line signals across the whole sky with a large dataset, establishing new upper limits on dark matter annihilation.

Findings

No significant line signals detected (max TS=24.3, global significance=0.54σ)

50 regions show weak excesses with TS>16

Constraints placed on dark matter annihilation cross section

Abstract

In order to search for the line-like signals in the Fermi-LAT data, we have analyzed totally 49152 regions of interest (ROIs) that cover the whole sky. No ROI displays a line signal with test statistic (TS) value above 25, while for 50 ROIs weak line-like excesses with ${\rm TS}>16$ are presented. The intrinsic significances of these potential signals are further reduced by the large trial factor introduced in such kind of analysis. For the largest TS value of 24.3 derived in our analysis, the corresponding global significance is only $0.54\sigma$. We thus do not find any significant line-like signal and set up constraints on the cross section of dark matter annihilating to gamma-ray lines, $\left<\sigma{v}\right>_{\gamma\gamma}$.