A targeted search for point sources of EeV photons with the Pierre Auger Observatory

TL;DR

This study uses the Pierre Auger Observatory to search for point sources of EeV photons, finding no evidence but setting upper limits that constrain astrophysical models of proton emission.

Contribution

It introduces a targeted search method for EeV photon sources using combined fluorescence and surface detector data, improving constraints on emission models.

Findings

No significant photon source detections were found.

Upper limits on photon flux constrain models of Galactic and extragalactic sources.

Results particularly impact predictions for the Galactic center region.

Abstract

Simultaneous measurements of air showers with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for EeV photon point sources. Several Galactic and extragalactic candidate objects are grouped in classes to reduce the statistical penalty of many trials from that of a blind search and are analyzed for a significant excess above the background expectation. The presented search does not find any evidence for photon emission at candidate sources, and combined $p$-values for every class are reported. Particle and energy flux upper limits are given for selected candidate sources. These limits significantly constrain predictions of EeV proton emission models from non-transient Galactic and nearby extragalactic sources, as illustrated for the particular case of the Galactic center region.