Prospects for detection of primordial black holes captured in cold dark matter haloes around massive objects

The capture of cold dark matter species, and especially primordial black ho les, during the formation of gravitationally bound objects is analyzed. It is shown that the best conditions for an efficient gravitational capture we re at the epoch preceding the galaxy formation, when the first astrophysica l objects with masses of the order of Jeans mass 10(5)-10(6) M-. were formi ng. Black hole haloes around old globular clusters, dark matter clusters an d Population III stars are considered, and in each case the total mass of t he halo and its luminosity due to the Hawking emission are found. Among all the objects considered, large (M greater than or similar to 10(5) M-.), ne arby (within similar to 5 kpc from the Sun) globular clusters are shown to provide the best prospects for detection of the black holes. First, black h ole haloes around the globular clusters have the highest brightness near 10 0 MeV, which is within the reach of EGRET capabilities, and provide distinc t observational features. Second, globular clusters are extensively studied at other wavelengths and represent a well-defined target for gamma-ray det ectors. We have also considered the probability of detecting an isolated bl ack hole bound to the Sun. Our estimates of the mass of gravitationally cap tured haloes are applicable to any cold dark matter particles.