First Cosmic Gamma-Ray Horizon Catalogue, 1CGH

Background

Light (EBL), we identified a subsample of 525 sources where moderate to severe gamma-ray absorption could be detected across the redshift range of 0 to 3. This work provides the most up-to-date compilation of detections above 10GeV, along with their redshift information. We condense extensive results from the literature, including reports on observational campaigns dedicated to blazars and gamma-ray sources, thereby delivering an unprecedented review of the redshift information for sources detected above 10GeV.

Additionally, we highlight key 1CGH sources where redshift information remains incomplete, offering guidance for future optical observation campaigns. The 1CGH catalogue aims to track the most significant sources for studying the gamma-ray transparency of the universe. Furthermore, it provides a targeted subsample where the EBL optical depth (tau(E,z)) can be robustly measured using Fermi-LAT data.