Clusters of Black Holes as Point-Like Gamma-ray Sources
  The possibility of identifying some of Galactic gamma-ray sources as clusters of primordial black holes is discussed. The known scenarios of supermassive black hole formation indicate the multiple formation of lower-mass black holes. Our analysis demonstrates that due to Hawking evaporation the cluster of black holes with masses about $10^{15}$ g could be observed as a gamma-ray source. The total mass of typical cluster is $\sim 10 M_\odot$. Detailed calculations have been performed on the basis of specific model of primordial black hole formation. 
K. M. Belotsky, A. V. Berkov, A. A. Kirillov, S. G. Rubin
astro-ph.HE astro-ph.CO