2022ApJ...927L..35D

The High Energy Stereoscopic System (H.E.S.S.) observatory has carried out a deep survey of the Galactic plane, in the course of which the existence of a significant number of (∼78) TeV γ-ray sources was confirmed, many of which remain unidentified. HESS J1828-099 is a point-like (Gaussian standard deviation < 0.°07) unidentified source among the 17 confirmed point-like sources in the H.E.S.S. Galactic Plane Survey (HGPS) catalog. This source is also unique because it does not seem to have any apparent association with any object detected at other wavelengths. We investigate the nature and association of HESS J1828-099 with multiwavelength observational data. A high-mass X-ray binary (HMXB)-composed of the pulsar XTE J1829-098 and a companion Be star-has been observed earlier in the X-ray and infrared bands, 14' away from HESS J1828-099. With 12 yr of Fermi-LAT γ-ray data, we explore the possibility of 4FGL J1830.2-1005 being the GeV counterpart of HESS J1828-099. Within the RXTE confidence region, a steep-spectrum (α_radio = -0.746 ± 0.284) plausible counterpart is detected in data from existing radio frequency surveys. In this Letter, we probe for the first time, using multiwavelength data, whether HESS J1828-099, 4FGL J1830.2-1005, and the HMXB system have a common origin. Our study indicates that HESS J1828-099 might be a TeV high-mass γ-ray binary source.