London, January 27 (ANI): Reports indicate that astronomers have used ESO's (European Southern Observatory's) Very Large Telescope (VLT) to detect a stellar-mass black hole much farther away than any other previously known.
The newly discovered black hole is in the spiral galaxy NGC 300, about six million light-years away from the Sun.
With a mass of about twenty times that of the Sun, it is also the second most massive stellar-mass black hole ever found and it is entwined with a star that will soon become a black hole itself.
With the new discovery, astronomers have now found three black holes with masses more than fifteen times that of the Sun, all of which are in galaxies outside our own.
The newly announced black hole lies in a spiral galaxy called NGC 300, six million light-years from Earth.
"This is the most distant stellar-mass black hole ever weighed, and it's the first one we've seen outside our own galactic neighborhood, the Local Group," said Paul Crowther, Professor of Astrophysics at the University of Sheffield and lead author of the paper reporting the study.
The black hole's curious partner is a Wolf-Rayet star, which also has a mass of about twenty times as much as the Sun.
Wolf-Rayet stars are near the end of their lives and expel most of their outer layers into their surroundings before exploding as supernovae, with their cores imploding to form black holes.
In 2007, an X-ray instrument aboard NASA's Swift observatory scrutinized the surroundings of the brightest X-ray source in NGC 300.
"We recorded periodic, extremely intense X-ray emission, a clue that a black hole might be lurking in the area," explained team member Stefania Carpano from ESA.
Thanks to new observations performed with the FORS2 instrument mounted on the VLT, astronomers have confirmed their earlier hunch.
The new data show that the black hole and the Wolf-Rayet star dance around each other in a diabolic waltz, with a period of about 32 hours.
The astronomers also found that the black hole is stripping matter away from the star as they orbit each other.
"This is indeed a very 'intimate' couple. How such a tightly bound system has been formed is still a mystery," said collaborator Robin Barnard. (ANI)