The First Data from the MACHO Experiment

Abstract

MAssive Compact Halo Objects such as brown dwarfs, Jupiters, and black holes are prime candidates to comprise the dark halo of our galaxy. Paczynski noted that objects (dubbed MACHOs) with masses in the range $10^{-6}M_\odot < M \simlt 100 M_\odot$. can be detected via gravitational microlensing of stars in the Magellanic Clouds with the caveat that only about one in $10^6$ stars will be lensed at any given time. Our group has recently begun a search for microlensing using a refurbished 1.27 meter telescope at the Mount Stromlo Observatory in Australia. Since the summer of 1992, we have been imaging up to $10^7$ stars a night in the Large Magellanic Cloud using our large format two-color $3.4\times 10^7$ pixel CCD camera. Here I report on our first results based on an analysis of $\sim 10^6$ of these stars. Although this is not enough data to make definitive statements about the nature of the dark matter, we are able to conclude that the rate of variable star background events is not larger than the expected MACHO signal.

et. al., 7 pages, UCRL-JC-11113606

Cited by in corpus (8)

• Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud
• Gravitational Microlensing in the Local Group
• Gaia Data Release 3: Microlensing Events from All Over the Sky
• Lens parameters for Gaia18cbf -- a long gravitational microlensing event in the Galactic plane
• Observing the Galactic Underworld: Predicting photometry and astrometry from compact remnant microlensing events
• Weighing stars from birth to death: mass determination methods across the HRD
• Gravitational Microlensing Results from Macho
• Finding the Brightest Galactic Bulge Microlensing Events with a Small Aperture Telescope and Image Subtraction