News Release Archive:

News Release 95 of 137

January 13, 2000 12:30 PM (EST)

News Release Number: STScI-2000-03

Lone Black Holes Discovered Adrift in the Galaxy


Image: Lone Black Hole Passes in Front of Star

Lone Black Hole Passes in Front of StarSTScI-PRC2000-03

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Two images of a crowded starfield as seen through a ground-based telescope show the subtle brightening of a star due to the effect of gravitational microlensing, where an invisible but massive foreground object passes in front of the star and amplifies its light. The dark lensing object is estimated to be a six-solar-mass black hole that is drifting alone among the stars.

A NASA Hubble Space Telescope image of the same field clearly resolves the lensed star and yields its true brightness. The Hubble observation was needed because the ground-based images do not tell how bright the lensed star actually was before (or after) it was lensed. The star fields where microlensing events are observed are so crowded with stars that the lensed star images are often blended together with images of unlensed stars. But with the Hubble images, astronomers can identify the lensed star and determine its normal brightness. The Hubble images were taken on June 15, 1999.

Object Name: MACHO-96-BLG-5

Image Type: Astronomical/Illustration

Credit (Left): NOAO, Cerro Tololo Inter-American Observatory

Credit (Right): NASA and Dave Bennett (University of Notre Dame, Indiana)


The above montage includes these images:

MACHO-96-BLG-5 WFPC2 Image Type: Astronomical MACHO-96-BLG-5 WFPC2 MACHO-96-BLG-5 CTIO Image Type: Astronomical MACHO-96-BLG-5 CTIO MACHO-96-BLG-5 CTIO Image Type: Astronomical MACHO-96-BLG-5 CTIO

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