• DOI:10.1093/mnras/stw426
• Corpus ID: 118375182

Black Hole, Neutron Star and White Dwarf Candidates from Microlensing with OGLE-III

@article{Wyrzykowski2015BlackHN,
  title={Black Hole, Neutron Star and White Dwarf Candidates from Microlensing with OGLE-III},
  author={Lukasz Wyrzykowski and Zuzanna Kostrzewa-Rutkowska and Jan Skowron and Krzysztof A. Rybicki and Przemek Mr{\'o}z and Szymon Kozłowski and Andrzej Udalski and Michał K. Szymański and Grzegorz Pietrzyński and Igor Soszyński and Krzysztof Ulaczyk and Paweł Pietrukowicz and Radosław Poleski and Michał Pawlak and Krystian Iłkiewicz and Nicholas J. Rattenbury},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2015},
  volume={458},
  pages={3012-3026}
}

• L. Wyrzykowski, Z. Kostrzewa-Rutkowska, +13 authors N. Rattenbury
• Published 16 September 2015
• Physics
• Monthly Notices of the Royal Astronomical Society

Most stellar remnants so far have been found in binary systems, where they interact with matter from their companions. Isolated neutron stars and black holes are difficult to find as they are dark, yet they are predicted to exist in our Galaxy in vast numbers.
We explored the OGLE-III database of 150 million objects observed in years 2001-2009 and found 59 microlensing events exhibiting a parallax effect due to the Earth's motion around the Sun. Combining parallax and brightness measurements from microlensing light curves with expected proper motions in the Milky Way, we identified 13 microlensing events which are consistent with having a white dwarf, neutron star or a black hole lens and we estimated their masses and distances. The most massive of our black hole candidates has 9.3 MSun and is at a distance of 2.4 kpc. The distribution of masses of our candidates indicates a continuum in mass distribution with no mass gap between neutron stars and black holes. We also present predictions on how such events will be observed by the astrometric Gaia mission.