Is the LMC Microlensing Due to an Intervening Dwarf Galaxy?
The MACHO Collaboration, C. Alcock, R. A. Allsman, D. R. Alves, T. S. Axelrod, A. Becker, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, M. J. Lehner, S. L. Marshall, D. Minniti, B. A. Peterson, M. R. Pratt, P. J. Quinn, A. W. Rodgers, A. Rorabeck, C. W. Stubbs, W. Sutherland, A. Tomaney, T. Vandehei, D. L. Welch
Abstract
The recent suggestion that the microlensing events observed towards the Large Magellanic Cloud are due to an intervening Sgr-like dwarf galaxy is examined. A search for foreground RR Lyrae in the MACHO photometry database yields 20 stars whose distance distribution follow the expected halo density profile. Cepheid and red giant branch clump stars in the MACHO database are consistent with membership in the LMC. There is also no evidence in the literature for a distinct kinematic population, for intervening gas, or for the turn-off of such a hypothetical galaxy. We conclude that if the lenses are in a foreground galaxy, it must be a particularly dark galaxy.
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