On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE

Krzysztof A. Rybicki; Łukasz Wyrzykowski; Jakub Klencki; Jos de Bruijne; Krzysztof Belczyński; Martyna Chruślińska

doi:10.1093/mnras/sty356

paper

On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE

arXiv:1802.03258 · doi:10.1093/mnras/sty356

Abstract

We investigate the impact of combining Gaia astrometry from space with precise, high cadence OGLE photometry from the ground. For the archival event OGLE3-ULENS-PAR-02, which is likely a black hole, we simulate a realistic astrometric time-series of Gaia measurements and combine it with the real photometric data collected by the OGLE project. We predict that at the end of the nominal 5 years of the Gaia mission, for the events brighter than $G \approx 15.5$ mag at the baseline, caused by objects heavier than 10 $M_{⊙}$ , it will be possible to unambiguously derive masses of the lenses, with accuracy between a few to 15 per cent. We find that fainter events ( $G < 17.5$ ) can still have their lens masses determined, provided that they are heavier than 30 $M_{⊙}$ . We estimate that the rate of astrometric microlensing events caused by the stellar-origin black holes is $\approx 4 \times 1 0^{- 7} y r^{- 1}$ , which implies, that after 5 years of Gaia operation and $\approx 5 \times 1 0^{6}$ bright sources in Gaia, it will be possible to identify few such events in the Gaia final catalogues.

arXiv comment17 pages, 13 figures; accepted for publication in MNRAS

On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE

Abstract

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