Surprise: Dwarf galaxy harbors supermassive black hole
The surprising discovery of a supermassive black hole in a small nearby galaxy has given astronomers a tantalizing look at how black holes and galaxies may have grown in the early history of the Universe. Finding a black hole a million times more massive than the Sun in a star-forming dwarf galaxy is a strong indication that supermassive black holes formed before the buildup of galaxies, the astronomers said. The galaxy, called Henize 2-10, 30 million light-years from Earth, has been studied for years, and is forming stars very rapidly. Irregularly shaped and about 3,000 light-years across (compared to 100,000 for our own Milky Way), it resembles what scientists think were some of the first galaxies to form in the early Universe.
"This galaxy gives us important clues about a very early phase of galaxy evolution that has not been observed before," said Amy Reines, a Ph.D. candidate at the University of Virginia.
Supermassive black holes lie at the cores of all "full-sized" galaxies. In the nearby Universe, there is a direct relationship -- a constant ratio -- between the masses of the black holes and that of the central "bulges" of the galaxies, leading them to conclude that the black holes and bulges affected each others' growth.
Two years ago, an international team of astronomers found that black holes in young galaxies in the early Universe were more massive than this ratio would indicate. This, they said, was strong evidence that black holes developed before their surrounding galaxies.
"Now, we have found a dwarf galaxy with no bulge at all, yet it has a supermassive black hole. This greatly strengthens the case for the black holes developing first, before the galaxy's bulge is formed," Reines said.
Reines, along with Gregory Sivakoff and Kelsey Johnson of the University of Virginia and the National Radio Astronomy Observatory (NRAO), and Crystal Brogan of the NRAO, observed Henize 2-10 with the National Science Foundation's Very Large Array radio telescope and with the Hubble Space Telescope. They found a region near the center of the galaxy that strongly emits radio waves with characteristics of those emitted by super-fast "jets" of material spewed outward from areas close to a black hole.
They then searched images from the Chandra X-Ray Observatory that showed this same, radio-bright region to be strongly emitting energetic X-rays. This combination, they said, indicates an active, black-hole-powered, galactic nucleus.
"Not many dwarf galaxies are known to have massive black holes," Sivakoff said.
While central black holes of roughly the same mass as the one in Henize 2-10 have been found in other galaxies, those galaxies all have much more regular shapes. Henize 2-10 differs not only in its irregular shape and small size but also in its furious star formation, concentrated in numerous, very dense "super star clusters."
"This galaxy probably resembles those in the very young Universe, when galaxies were just starting to form and were colliding frequently. All its properties, including the supermassive black hole, are giving us important new clues about how these black holes and galaxies formed at that time," Johnson said.
Source: National Radio Astronomy Observatory
Articles on the same topic
- Taking the pulse of a black hole systemWed, 12 Jan 2011, 22:33:30 UTC
- Astronomers discover close-knit pairs of massive black holesWed, 12 Jan 2011, 18:55:17 UTC
Other sources
- Astronomers calculate mass of largest black hole yetfrom PhysorgFri, 14 Jan 2011, 23:00:19 UTC
- Taking the pulse of a black hole systemfrom Science DailyFri, 14 Jan 2011, 4:30:42 UTC
- At 6.6 Billion Suns, The Largest Black Hole Ever Measured Could Swallow Our Solar Systemfrom PopSciThu, 13 Jan 2011, 21:20:36 UTC
- Taking the Pulse of a Black Hole Systemfrom Newswise - ScinewsThu, 13 Jan 2011, 3:30:22 UTC
- Astronomers discover 16 black-hole pairsfrom UPIThu, 13 Jan 2011, 0:50:11 UTC
- Taking the pulse of a black hole systemfrom Science BlogThu, 13 Jan 2011, 0:30:37 UTC
- Most Massive Black Hole Known Tips Scales at 6.6 Billion Sunsfrom Space.comThu, 13 Jan 2011, 0:30:19 UTC
- Taking the pulse of a black hole system (w/ Video)from PhysorgWed, 12 Jan 2011, 23:50:14 UTC
- Neighboring black hole puts on weightfrom Sciencenews.orgWed, 12 Jan 2011, 23:30:18 UTC
- Tiny Galaxy Hiding a Big Secretfrom CBSNews - ScienceWed, 12 Jan 2011, 19:41:03 UTC
- Close-knit pairs of supermassive black holes discovered in merging galaxiesfrom Science DailyWed, 12 Jan 2011, 19:21:35 UTC
- Astronomers discover close-knit pairs of massive black holesfrom PhysorgWed, 12 Jan 2011, 18:52:46 UTC
- Tiny Galaxy Hiding a Big Secretfrom CBSNews - ScienceWed, 12 Jan 2011, 16:30:23 UTC
- Mystery Deepens in Origin of Violent Black Holesfrom Space.comTue, 11 Jan 2011, 21:03:04 UTC
- Ginormous Black Hole May Solve Longstanding Mysteryfrom Space.comTue, 11 Jan 2011, 21:01:40 UTC
- Dwarf galaxy solves supermassive mysteryfrom Physics WorldMon, 10 Jan 2011, 22:20:12 UTC
- Huge Black Hole Found in Dwarf Galaxyfrom National GeographicMon, 10 Jan 2011, 19:00:09 UTC
- Physicists create sonic black hole in the labfrom PhysorgMon, 10 Jan 2011, 14:00:24 UTC
- Surprise: Dwarf galaxy harbors supermassive black holefrom Science BlogMon, 10 Jan 2011, 8:20:08 UTC
- Dwarf galaxy harbors supermassive black holefrom Science DailyMon, 10 Jan 2011, 2:30:20 UTC
- Surprise: Dwarf galaxy harbors supermassive black holefrom PhysorgSun, 9 Jan 2011, 19:50:49 UTC
- Hole's on First?: New Evidence Shows Black Hole Growth Preceding Galactic Formationfrom Scientific AmericanSun, 9 Jan 2011, 19:00:27 UTC
- Ginormous Black Hole May Solve Longstanding Mysteryfrom Space.comSun, 9 Jan 2011, 18:50:23 UTC