Experimental limits on primordial black hole dark matter from the first 2 yr of Kepler data

We present our analysis on new limits of the dark matter (DM) halo consisting of primordial black holes (PBHs) or massive compact halo objects. We present a search of the first two yr 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 that are moving through the Kepler field. We discuss the potential of detecting comets using the Kepler light curves, 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 × 10^–9 M _☉ to 10^–7 M _☉. 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.