Gravitational Microlensing Events Due to Stellar-Mass Black Holes

  title={Gravitational Microlensing Events Due to Stellar-Mass Black Holes},
  author={David P. Bennett and Andrew C. Becker and J. L. Quinn and Austin Bede Tomaney and Charles R. Alcock and Robyn A. Allsman and David Randall Alves and Timothy S. Axelrod and Johannes J. Calitz and K. H. Cook and Andrew J. Drake and P. Chris Fragile and Kenneth C. Freeman and Marla C. Geha and Kim Griest and B R Johnson and Stefan C. Keller and Chris Laws and Matthew J. Lehner and Simon L. Marshall and Dante Minniti and Cailin Anne Nelson and Bruce A. Peterson and Piotr Popowski and Mark Robin Pratt and Peter Quinn and Sun Hong Rhie and Christopher W. Stubbs and William J. Sutherland and Thor Vandehei and Douglas L. Welch},
  journal={The Astrophysical Journal},
  pages={639 - 659}
We present an analysis of the longest timescale microlensing events discovered by the MACHO Collaboration during a 7 year survey of the Galactic bulge. We find six events that exhibit very strong microlensing parallax signals due, in part, to accurate photometric data from the GMAN and MPS collaborations. The microlensing parallax fit parameters are used in a likelihood analysis, which is able to estimate the distances and masses of the lens objects based on a standard model of the Galactic… 

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