Galactic Bulge Microlensing Events with Clump Giants as Sources

P. Popowski; C. Alcock; R. A. Allsman; D. R. Alves; T. S. Axelrod; A. C. Becker; D. P. Bennett; K. H. Cook; A. J. Drake; K. C. Freeman; M. Geha; K. Griest; M. J. Lehner; S. L. Marshall; D. Minniti; C. A. Nelson; B. A. Peterson; M. R. Pratt; P. J. Quinn; C. W. Stubbs; W. Sutherland; A. B. Tomaney; T. Vandehei; D. Welch

arXiv · astro-ph/0005466

Galactic Bulge Microlensing Events with Clump Giants as Sources

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Abstract

We present preliminary results of the analysis of 5 years of MACHO data on the Galactic bulge microlensing events with clump giants as sources. In particular, we discuss: 1) the selection of `giant' events, 2) distribution of impact parameters, 3) distribution of event durations, 4) the concentration of long duration events in MACHO field 104 centered on (l,b) = (3.1,-3.0). We report the preliminary average optical depth of (2.0 +/- 0.4) x 10^{-6} (internal) at (l,b) = (3.9,-3.8). We discuss future work and prospects for building a coherent model of the Galaxy.

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P. Popowski, C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, A. J. Drake, K. C. Freeman, M. Geha, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, C. A. Nelson, B. A. Peterson, M. R. Pratt, P. J. Quinn, C. W. Stubbs, W. Sutherland, A. B. Tomaney, T. Vandehei, D. Welch. 2000-05-23. Galactic Bulge Microlensing Events with Clump Giants as Sources. https://arxiv.org/abs/astro-ph/0005466

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