Experimental Limits on Primordial Black Hole Dark Matter from the First Two Years of Kepler Data

TL;DR

This study used Kepler data to search for gravitational microlensing by primordial black holes, setting new limits on their contribution to dark matter in the mass range of 2x10^-9 to 10^-7 solar masses.

Contribution

First to analyze Kepler data for PBH microlensing signatures, providing new constraints on PBH dark matter in a previously unexplored mass range.

Findings

No microlensing candidates found.

PBHs in the 2x10^-9 to 10^-7 solar masses range cannot account for all dark matter.

Closed a full order of magnitude in the allowed PBH mass window.

Abstract

We present the analysis on our new limits of the dark matter (DM) halo consisting of primordial black holes (PBHs) or massive compact halo objects (MACHOs). We present a search of the first two years of publicly available Kepler mission data for potential signatures of gravitational microlensing caused by these objects, as well as an extensive analysis of the astrophysical sources of background error. These include variable stars, flare events, and comets or asteroids which are moving through the Kepler field. We discuss the potential of detecting comets using the Kepler lightcurves, presenting measurements of two known comets and one unidentified object, most likely an asteroid or comet. After removing the background events with statistical cuts, we find no microlensing candidates. We therefore present our Monte Carlo efficiency calculation in order to constrain the PBH DM with masses in the range of 2 x 10^-9 solar masses to 10^-7 solar masses. We find that PBHs in this mass range cannot make up the entirety of the DM, thus closing a full order of magnitude in the allowed mass range for PBH DM.