Microlensing constraints on primordial black holes with the Subaru/HSC Andromeda observation

Hiroko Niikura, Masahiro Takada, Naoki Yasuda, Robert H. Lupton, Takahiro Sumi, Surhud More, Toshiki Kurita, Sunao Sugiyama, Anupreeta More, Masamune Oguri, Masashi Chiba

Research output: Contribution to journalArticlepeer-review


Primordial black holes (PBHs) have long been suggested as a viable candidate for the elusive dark matter (DM). The abundance of such PBHs has been constrained using a number of astrophysical observations, except for a hitherto unexplored mass window of MPBH= [10-14, 10-9]M. Here we carry out a dense-cadence (2 min sampling rate), 7 hour-long observation of the Andromeda galaxy (M31) with the Subaru Hyper Suprime-Cam to search for microlensing of stars in M31 by PBHs lying in the halo regions of the Milky Way (MW) and M31. Given our simultaneous monitoring of more than tens of millions of stars in M31, if such light PBHs make up a significant fraction of DM, we expect to find many microlensing events for the PBH DM scenario. However, we identify only a single candidate event, which translates into the most stringent upper bounds on the abundance of PBHs in the mass range MPBH≃ [10-11, 10-6]M.

Original languageEnglish
JournalUnknown Journal
Publication statusPublished - 2017 Jan 9

ASJC Scopus subject areas

  • General

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