Identification of the Microlens in Event MACHO-LMC-20

Abstract

We report on the identification of the lens responsible for microlensing event MACHO-LMC-20. As part of a \textit{Spitzer}/IRAC program conducting mid-infrared follow-up of the MACHO Large Magellanic Cloud microlensing fields, we discovered a significant flux excess at the position of the source star for this event. These data, in combination with high resolution near-infrared \textit{Magellan}/PANIC data has allowed us to classify the lens as an early M dwarf in the thick disk of the Milky Way, at a distance of $\sim 2$ kpc. This is only the second microlens to have been identified, the first also being a M dwarf star in the disk. Together, these two events are still consistent with the expected frequency of nearby stars in the Milky Way thin and thick disks acting as lenses.

6 pages, 4 figures, submitted to ApJ Letters

References in corpus (10)

• The Infrared Array Camera (IRAC) for the Spitzer Space Telescope
• The Magellanic Clouds Photometric Survey: The Large Magellanic Cloud Stellar Catalog and Extinction Map
• PANIC: A Near-infrared Camera for the Magellan Telescopes
• LMC Self-lensing from a new perspective
• Lightcurve Classification in Massive Variability Surveys II: Transients towards the Large Magellanic Cloud
• The Stellar Halo in the Large Magellanic Cloud: Mass, Luminosity, and Microlensing Predictions
• Resolving the Nature of the LMC Microlensing Event LMC-5
• Contamination in the MACHO dataset and the puzzle of LMC Microlensing
• Photometric Confirmation of MACHO Large Magellanic Cloud Microlensing Events
• Microlensing by the Halo MACHOs with Spatially Varying Mass Function

Cited by in corpus (5)

• Astrophysical Applications of Gravitational Microlensing
• The OGLE View of Microlensing towards the Magellanic Clouds. III. Ruling out sub-solar MACHOs with the OGLE-III LMC data
• The OGLE View of Microlensing towards the Magellanic Clouds. I. A Trickle of Events in the OGLE-II LMC data
• The Origin of the Microlensing Events Observed Towards the LMC and the Stellar Counterpart of the Magellanic Stream
• LMC self lensing for OGLE-II microlensing observations