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

Green, Anne M. (2017) Astrophysical uncertainties on stellar microlensing constraints on multi-solar mass primordial black hole dark matter. Physical Review D . ISSN 2470-0029 (In Press)

[img] PDF - Repository staff only until 4 September 2017. - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (347kB)

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.

Item Type: Article
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Physics and Astronomy
Depositing User: Green, Anne
Date Deposited: 04 Aug 2017 08:21
Last Modified: 04 Aug 2017 22:31
URI: http://eprints.nottingham.ac.uk/id/eprint/44638

Actions (Archive Staff Only)

Edit View Edit View