Astronomers led by Dr Dheeraj Pasham at the University of Maryland have determined the mass of a black hole known as M82 X-1, which is located in the nearby irregular galaxy Messier 82.
This composite image shows the nearby galaxy Messier 82. The intermediate-mass black hole M82 X-1 is the brightest object in the inset. Image credit: full-field – X-ray: NASA / CXC / JHU / D. Strickland; optical: NASA / ESA / STScI / AURA/ Hubble Heritage Team; IR: NASA / JPL-Caltech /Univ. of AZ / C. Engelbracht; inset – NASA / CXC / Tsinghua University / H. Feng et al.
Scientists know that black holes ranging from about 10 times to 100 times the Sun’s mass are the remnants of dying stars, and that supermassive black holes, more than 1,000,000 times the mass of the Sun, inhabit the centers of most galaxies.
But scattered across the Universe are a few apparent black holes of a more mysterious type. Ranging from 100 to 10,000 solar masses, these intermediate-mass black holes are so hard to measure that even their existence is sometimes disputed.
Since the 1970s scientists have observed a few hundred intermediate-mass black holes, but they couldn’t measure their mass.
Dr Pasham and his two colleagues, Dr Richard Mushotzky of the University of Maryland and Dr Tod Strohmayer of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, have succeeded in accurately measuring – and thus confirming the existence of – the intermediate-mass black hole M82 X-1.
Discovered in 1999 by NASA’s Chandra X-ray Observatory, this black hole lies in Messier 82 (also known as M82, NGC 3034 or Cigar Galaxy), an irregular galaxy located within the constellation Ursa Major, about 12 million light-years away from our planet.
According to Dr Pasham’s team, M82 X-1 has an estimated mass of about 428 solar masses.
The finding has been published online in the journal Nature.
_____
Dheeraj R. Pasham et al. A 400-solar-mass black hole in the galaxy M82. Nature, published online August 17, 2014; doi: 10.1038/nature13710
