Galactic Bulge Microlensing Events from the MACHO Collaboration Academic Article uri icon

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abstract

  • We present a catalog of 450 high signal-to-noise microlensing events observed by the MACHO collaboration between 1993 and 1999. The events are distributed throughout our fields and, as expected, they show clear concentration toward the Galactic center. No optical depth is given for this sample since no blending efficiency calculation has been performed, and we find evidence for substantial blending. In a companion paper we give optical depths for the sub-sample of events on clump giant source stars, where blending is not a significant effect. Several events with sources that may belong to the Sagittarius dwarf galaxy are identified. For these events even relatively low dispersion spectra could suffice to classify these events as either consistent with Sagittarius membership or as non-Sagittarius sources. Several unusual events, such as microlensing of periodic variable source stars, binary lens events, and an event showing extended source effects are identified. We also identify a number of contaminating background events as cataclysmic variable stars.

authors

  • Thomas, CL
  • Griest, K
  • Popowski, P
  • Cook, KH
  • Drake, AJ
  • Minniti, D
  • Myer, DG
  • Alcock, C
  • Allsman, RA
  • Alves, DR
  • Axelrod, TS
  • Becker, AC
  • Bennett, DP
  • Freeman, KC
  • Geha, M
  • Lehner, MJ
  • Marshall, SL
  • Nelson, CA
  • Peterson, BA
  • Quinn, PJ
  • Stubbs, CW
  • Sutherland, W
  • Vandehei, T
  • Welch, Douglas L

publication date

  • October 2005