First Microlensing Events From The MEGA Survey Of M31

Jelte T. A. de Jong; Konrad H. Kuijken; Arlin P. S. Crotts; Penny D. Sackett; Will J. Sutherland; Robert R. Uglesich; Edward A. Baltz; Patrick Cseresnjes; Geza Gyuk; Lawrence M. Widrow; the MEGA collaboration

doi:10.1051/0004-6361:20031734

arXiv · astro-ph/0307072

First Microlensing Events From The MEGA Survey Of M31

Jelte T. A. de Jong·Konrad H. Kuijken·Arlin P. S. Crotts·Penny D. Sackett·Will J. Sutherland·Robert R. Uglesich·Edward A. Baltz·Patrick Cseresnjes·Geza Gyuk·Lawrence M. Widrow·the MEGA collaboration

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Abstract

We present the first M31 candidate microlensing events from the Microlensing Exploration of the Galaxy and Andromeda (MEGA) survey. MEGA uses several telescopes to detect microlensing towards the nearby Andromeda galaxy, M31, in order to establish whether massive compact objects are a significant contribution to the mass budget of the dark halo of M31. The results presented here are based on observations with the Isaac Newton Telescope on La Palma, during the 1999/00 and 2000/01 observing seasons. In this data set, 14 variable sources consistent with microlensing have been detected, 12 of which are new and 2 have been reported previously by the POINT-AGAPE group. A preliminary analysis of the spatial and timescale distributions of the candidate events support their microlensing nature. We compare the spatial distributions of the candidate events and of long-period variable stars, assuming the chances of finding a long-period variable and a microlensing event are comparable. The spatial distribution of our candidate microlensing events is more far/near side asymmetric than expected from the detected long-period variable distribution. The current analysis is preliminary and the asymmetry not highly significant, but the spatial distribution of candidate microlenses is suggestive of the presence of a microlensing halo.

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Jelte T. A. de Jong, Konrad H. Kuijken, Arlin P. S. Crotts, Penny D. Sackett, Will J. Sutherland, Robert R. Uglesich, Edward A. Baltz, Patrick Cseresnjes, Geza Gyuk, Lawrence M. Widrow, the MEGA collaboration. 2003-09-26. First Microlensing Events From The MEGA Survey Of M31. https://doi.org/10.1051/0004-6361%3A20031734

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