A Candidate M31/M32 Intergalactic Microlensing Event

Abstract

We report the discovery of a microlensing candidate projected 2'54" from the center of M32, on the side closest to M31. The blue color (R-I= 0.00 +/- 0.14) of the source argues strongly that it lies in the disk of M31, while the proximity of the line of sight to M32 implies that this galaxy is the most likely host of the lens. If this interpretation is correct, it would confirm previous arguments that M32 lies in front of M31. We estimate that of order one such event or less should be present in the POINT-AGAPE data base. If more events are discovered in this direction in a dedicated experiment, they could be used to measure the mass function of M32 up to an unknown scale factor. By combining microlensing observations of a binary-lens event with a measurement of the M31-M32 relative proper motion using the astrometric satellites SIM or GAIA, it will be possible to measure the physical separation of M31 and M32, the last of the six phase-space coordinates needed to assign M32 an orbit.

Submitted to ApJ Letters. 13 pages, 2 figures

References in corpus (1)

• A Candidate M31/M32 Intergalactic Microlensing Event

Cited by in corpus (21)

• POINT-AGAPE Pixel Lensing Survey of M31 : Evidence for a MACHO contribution to Galactic Halos
• The Point-Agape survey: 4 high signal-to-noise ratio microlensing candidates detected towards M31
• The Anomaly in the Candidate Microlensing Event PA-99-N2
• The Dearth of UV-Bright Stars in M32: Implications for Stellar Evolution Theory
• The Wendelstein Calar Alto Pixellensing Project(WeCAPP): First MACHO Candidates
• First Microlensing Events From The MEGA Survey Of M31
• Lightcurve Classification in Massive Variability Surveys
• The POINT-AGAPE Survey I: The Variable Stars in M31
• MACHOs in M31? Absence of evidence but not evidence of absence
• Signatures of the M31-M32 Galactic Collision
• Pixel lensing: Microlensing towards M31
• A Candidate M31/M32 Intergalactic Microlensing Event
• Discovery of a Very Bright, Nearby Gravitational Microlensing Event
• Microlensing towards M31 with MDM data
• The possibility of detecting planets in the Andromeda Galaxy
• First microlensing candidate towards M31 from the Nainital Microlensing Survey
• Automated Detection of Classical Novae with Neural Networks
• Theory of pixel lensing towards M31 -- II. The velocity anisotropy and flattening of the MACHO distribution
• HST Imaging of MEGA Microlensing Candidates in M31
• The POINT-AGAPE Survey: Comparing Automated Searches of Microlensing Events toward M31
• Pixel lensing observations towards globular clusters