Microlensing towards M31 with MDM data

Abstract

We report the final analysis of a search for microlensing events in the direction of the Andromeda galaxy, which aimed to probe the MACHO composition of the M31 halo using data collected during the 1998-99 observational campaign at the MDM observatory. In a previous paper, we discussed the results from a first set of observations. Here, we deal with the complete data set, and we take advantage of some INT observations in the 1999-2000 seasons. This merging of data sets taken by different instruments turns out to be very useful, the study of the longer baseline available allowing us to test the uniqueness characteristic of microlensing events. As a result, all the candidate microlensing events previously reported turn out to be variable stars. We further discuss a selection based on different criteria, aimed at the detection of short--duration events. We find three candidates whose positions are consistent with self--lensing events, although the available data do not allow us to conclude unambiguously that they are due to microlensing.

Accepted for publication in Astronomy and Astrophysics

References in corpus (3)

• The Point-Agape survey: 4 high signal-to-noise ratio microlensing candidates detected towards M31
• Microlensing towards the Large Magellanic Cloud
• A Candidate M31/M32 Intergalactic Microlensing Event

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• MACHOs in M31? Absence of evidence but not evidence of absence
• The Angstrom Project: a microlensing survey of the structure and composition of the bulge of the Andromeda galaxy
• Pixel lensing: Microlensing towards M31
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• Candidate microlensing events from M31 observations with the Loiano telescope
• Monte Carlo analysis of the MEGA microlensing events towards M31
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• First microlensing candidate towards M31 from the Nainital Microlensing Survey
• The Angstrom Project Alert System: real-time detection of extragalactic microlensing
• Probing MACHOs by observation of M31 pixel lensing with the 1.5m Loiano telescope
• Influence of magnification threshold on pixel lensing optical depth, event rate and time scale distributions towards M31
• M31 Pixel Lensing PLAN Campaign: MACHO Lensing and Self Lensing Signals
• A critical analysis of the recent OGLE limits on stellar mass primordial black holes in the halo of the Milky Way
• The POINT-AGAPE Survey: Comparing Automated Searches of Microlensing Events toward M31
• Probing MACHOs Toward the Galactic Bulge
• Variable Star Candidates in an ACS Field of M31
• Microlensing Surveys of M31 in the Wide Field Imaging Era