Primordial Black Hole Cosmology
After aLIGO detected the gravitational wave (GW) 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/Pop.II stars,
one of the attractive candidates of those BHs should be Primordial Black Holes
(PBHs). See M.Sasaki, T.Suyama, S.Yokoyama and T.Tanaka (arXiv:1603.08338 [astro-ph.CO]).
The PBHs can be produced in the early radiation or matter dominated Universe due to spherical
collapses of regions which have a large curvature perturbation produced by inflation.
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 due to cosmological accretions
onto PBHs (arXiv:1707.04206 [astro-ph.CO]), cosmological/gamma-ray/cosmicrays bounds on evaporating PBHs (arXiv:0912.5297 [astro-ph.CO]),
Higgs phenomenology (arXiv:1708.02138 [hep-ph]),
stochastic GWs (arXiv:1903.05924 [astro-ph.CO]), dark matter (arXiv:1802.06785 [astro-ph.CO]),
ultra-compact mini halo formations (arXiv:1712.08820 [astro-ph.CO]) and so on.
If time permitted, I will mention the current status of concreteinflation modes based on particle physics which can successfully produce PBHs.