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Astrophysical uncertainties on stellar microlensing constraints on multi-solar mass primordial black hole dark matter

Green, Anne M.

Astrophysical uncertainties on stellar microlensing constraints on multi-solar mass primordial black hole dark matter Thumbnail


Authors

Profile image of ANNE GREEN

ANNE GREEN anne.green@nottingham.ac.uk
Professor of Physics



Abstract

There has recently been interest in multi-Solar mass Primordial Black Holes (PBHs) as a dark matter (DM) candidate. There are various microlensing, dynamical and accretion constraints on the abundance of PBHs in this mass range. Taken at face value these constraints exclude multi-Solar mass PBHs making up all of the DM for both delta-function and extended mass functions. However the stellar microlensing event rate depends on the density and velocity distribution of the compact objects along the line of sight to the Magellanic Clouds. We study the dependence of the constraints on the local dark matter density and circular speed and also consider models where the velocity distribution varies with radius. We find that the largest mass constrained by stellar microlensing can vary by an order of magnitude. In particular the constraints are significantly weakened if the velocity dispersion of the compact objects is reduced. The change is not sufficiently large to remove the tension between the stellar microlensing and dynamical constraints. However this demonstrates that it is crucial to take into account astrophysical uncertainties when calculating and comparing constraints. We also confirm the recent finding that the tension between the constraints is in fact increased for realistic, finite width mass functions.

Citation

Green, A. M. (2017). Astrophysical uncertainties on stellar microlensing constraints on multi-solar mass primordial black hole dark matter. Physical Review D, 96, Article 043020. https://doi.org/10.1103/PhysRevD.96.043020

Journal Article Type Article
Acceptance Date Aug 2, 2017
Publication Date Aug 31, 2017
Deposit Date Aug 4, 2017
Publicly Available Date Aug 31, 2017
Journal Physical Review D
Print ISSN 2470-0010
Electronic ISSN 2470-0029
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 96
Article Number 043020
DOI https://doi.org/10.1103/PhysRevD.96.043020
Public URL https://nottingham-repository.worktribe.com/output/880549
Publisher URL https://journals.aps.org/prd/abstract/10.1103/PhysRevD.96.043020
Contract Date Aug 4, 2017

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