Revisiting constraints on asteroid-mass primordial black holes as dark matter candidates
AffiliationUniv Arizona, Dept Astron & Steward Observ
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationPaulo Montero-Camacho et al JCAP08(2019)031
Rights© 2019 IOP Publishing Ltd and Sissa Medialab
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at firstname.lastname@example.org.
AbstractAs the only dark matter candidate that does not invoke a new particle that survives to the present day, primordial black holes (PBHs) have drawn increasing attention recently. Up to now, various observations have strongly constrained most of the mass range for PBHs, leaving only small windows where PBHs could make up a substantial fraction of the dark matter. Here we revisit the PBH constraints for the asteroid-mass window, i.e., the mass range 3.5 x 10(-17) M-circle dot < m(PBH) < 4 x 10(-12) M-circle dot. We revisit 3 categories of constraints. (1) For optical microlensing, we analyze the finite source size and diffractive effects and discuss the scaling relations between the event rate, m(PBH) and the event duration. We argue that it will be difficult to push the existing optical microlensing constraints to much lower mPBH. (2) For dynamical capture of PBHs in stars, we derive a general result on the capture rate based on phase space arguments. We argue that survival of stars does not constrain PBHs, but that disruption of stars by captured PBHs should occur and that the asteroid-mass PBH hypothesis could be constrained if we can work out the observational signature of this process. (3) For destruction of white dwarfs by PBHs that pass through the white dwarf without getting gravitationally captured, but which produce a shock that ignites carbon fusion, we perform a 1+1D hydrodynamic simulation to explore the post-shock temperature and relevant timescales, and again we find this constraint to be ineffective. In summary, we find that the asteroid-mass window, which was previously constrained due to femtolensing, WD survival, optical microlensing, and neutron star capture is no longer constrained. Hence, the asteroid-mass window remains open for PBHs to account for all the dark matter.
Note12 month embargo; published online: 23 August 2019
VersionFinal accepted manuscript
SponsorsSimons Foundation; US Department of Energy; NSF; NASA; NASA ROSES ATP [16-ATP16-0084]; NASA ADAP [16-ADAP16-0116]