Photon Bunching at TeV Energies

Harwit, Protheroe, and Biermann (1999) recently proposed that BoseEinstein photon bunching might significantly affect the interpretation of Cerenkov counts of TeV gamma photons. Here, we show that a combination of two recent results of Aharonian et al. (2000) and Aharonian et al. (2001) permits us to set new, more stringent upper limits of ∼< 10% on the fractional amount of photon bunching in the 7-10 TeV radiation from Markarian 501. Potential bunching at even higher energies should nevertheless continue to be investigated for this and other TeV sources, since a clear understanding of TeV energy spectra is required to unambiguously determine the spectral energy density of the mid-infrared extragalactic background. Subject headings: gamma rays: observations; BL Lacertae objects: individual (Markarian 501); radiation mechanisms: general; infrared: diffuse radiation