MACHOs

MACHOs have been long standing candidates for Galactic dark matter. In 1986, it was suggested that the microlensing of sources in dense stellar fields could constrain the mass fraction of MACHOs in the dark halo. After 10 years of experimental search, MACHOs have been ruled out as major contributors to Galactic dark matter over a wide mass range. However, the explanation of observational results towards the Large Magellanic Cloud is still controversial.