A Short-Timescale Candidate Microlensing Event in the POINT-AGAPE Pixel Lensing Survey of M31

• DOI: 10.1086/320681
• Publication Date: 2002-07-26T18:26:20Z
• Authors: M. Aurière; P. Baillon; A. Bouquet; B. J. Carr; M. Crézé; N. W. Evans; Y. Giraud-Héraud; A. Gould; P. C. Hewett; J. Kaplan; E. Kerins; E. Lastennet; Y. Le Du; A.-L. Melchior; S. Paulin-Henriksson; S. J. Smartt; D. Valls-Gabaud
• Keywords: Gravitational microlensing; Agape

We report the discovery of a short-duration microlensing candidate in northern field POINT-AGAPE pixel lensing survey toward M31. Almost certainly, source star has been identified on Hubble Space Telescope archival images, allowing us to infer an Einstein crossing time tE = 10.4 days, maximum magnification Amax ~ 18, and lens-source proper motion μrel > 0.3 μas day-1. The event projected separation 8' from center M31, beyond bulk stellar lens population. There are three plausible identifications/locations for object: massive compact halo object (MACHO) either M31 or Milky Way, disk. most probable mass is 0.06 M☉ MACHO, 0.02 Way 0.2 lens. While interpretation possible, MACHO fractions above 20%.