Speaker
Description
Primordial black holes (PBH) with masses below approximately 10$^{15}$ g are expected to emit gamma rays with energies above a few tens of MeV via Hawking radiation. Previous searches for PBH evaporation signal have focused on either short timescale bursts of TeV photons corresponding to last moments of PBH lifetime or the contribution of PBHs to the isotropic gamma-ray emission. We show that, in case of individual PBHs, the Fermi LAT is most sensitive to PBHs with temperatures near 16 GeV, which can be detected out to a distance of about 0.03 pc. These PBHs have lifetimes of a few years and would appear as potentially moving point sources. We develop a new algorithm to detect the proper motion of a gamma-ray point source (PS) and apply it to unassociated PS in the third Fermi-LAT source catalog (3FGL). None of unassociated PS that have spectra consistent with PBH evaporation show significant proper motion. The derived 99% confidence limit on PBH evaporation rate in the vicinity of the Earth is similar to the limits obtained with ground-based gamma-ray observatories.
