Cosmic Enigma: Ultra-High-Energy Gamma-Ray Source Still Unidentified
Astronomers studying the ultra-high-energy gamma-ray source LHAASO J2108+5157—detected with energies above 100 TeV—have not found a counterpart at radio, optical, or infrared wavelengths. A Spanish team used CAHA near-infrared data to search for a possible microquasar or related structure, but while a radio source with bipolar morphology was identified, its near-infrared properties indicate it is likely an unrelated background radio galaxy. The emitter remains mysterious and distance is unknown, highlighting the need for deeper observations to decipher its origin.