The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is an extensive air shower array located in Puebla, Mexico. The closest radio galaxy within the HAWC * Speaker.

The recent observation of GRB 221009A by LHAASO at TeV energies has challenged the accepted emission mechanisms that describe the late emission of GRBs. Given the estimated distance of the event, z=0.151, TeV emission was not expected to be detected due to attenuation with the EBL. For this reason, light dark matter candidates such as ALPs have been proposed to explain the arrival of these TeV photons by assuming either an initial population of TeV photons or ALPs during the evolution of the GRB. In this sense, the detection from LHAASO might be useful to study the parameter space and production of ALPs. In this study we present the constrains on the ALPs parameter space by exploring different temporal profiles for the TeV emission from possible ALP production in the GRB 221009A.

With an instantaneous field of view of 2 sr and a duty cycle > 95%, the High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory is a perfect instrument for monitoring variable TeV sources. Because radio galaxies are a type of Active Galactic Nuclei (AGN) with their jets misaligned with respect to our line of sight, they may help us to probe the physics of very-high-energy (VHE) emission processes in these objects. Three out of four radio galaxies that have been detected at TeV energies by other facilities are located within the field of view of the HAWC Observatory: M87, NGC 1275, and 3C 264. A search for TeV gamma rays at their locations yields no statistically significant excess of counts. We present corresponding upper limits for each radio galaxy and light curves covering 3 years of data taken with HAWC.