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After aLIGO detected the gravitational wave produced by mergers of binary black holes (BHs), researchers have aggressively studied the origin of the BHs with masses of the order of O(10) M_sun. In addition to astrophysical origins through evolutions of Pop.III stars, one of the attractive candidates of those BHs should be Primordial Black Holes (PBHs). The PBHs can be produced in the early radiation dominated Universe due to spherical collapses of regions which have a large density perturbation. I will review the current status of cosmological and astrophysical constraints on PBHs with introducing my own latest bounds on PBHs in terms of polarization of Cosmic Microwave Background photons (arXiv:1707.04206 [astro-ph.CO]), cosmological bounds on evaporating PBHs (arXiv:0912.5297 [astro-ph.CO]), Higgs phenomenology (arXiv:1708.02138 [hep-ph]) and so on. If time permitted, I will mention cosmological accretions of baryon onto PBHs and implications for a seed of Super-Massive BHs (in progress). |
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