A whopping 345 possible intermediate-mass black holes (IMBHs) have recently been discovered, the Chandra X-ray Observatory announced on Thursday. These fascinating objects are notoriously elusive, with only a handful of candidates being uncovered so far.
In fact, the first solid evidence that they even exist was obtained only in the past years and came from observations with Chandra, NASA’s Swift Satellite, and the European Space Agency’s (ESA) XMM-Newton X-ray space observatory, the Inquisitr reported in June.
According to NASA, IMBHs are, just like the name points out, black holes of intermediate mass, which fall right between the stellar mass variety frequently studied by astronomers and the supermassive black holes at the heart of each major galaxy. This intriguing class of black holes hold between one hundred and several hundred thousand times the mass of our sun.
The newly discovered IMBHs have been spotted in dwarf galaxies, both distant and nearby, and are described in a pair of studies conducted by two separate teams using the Chandra COSMOS-Legacy survey. This vast collection of data encompasses observations from several powerful telescopes managed both by NASA and ESA.
“We may have found that dwarf galaxies are a haven for these missing middleweight black holes,” said Mar Mezcua of the Institute of Space Sciences in Spain, leader of one of the teams, who published their findings in the journal Monthly Notices of the Royal Astronomical Society.
“We didn’t just find a handful of IMBHs — we may have found dozens,” she pointed out.
Study No. 1
Mezcua’s team ended up spotting 40 growing black holes nestled within dwarf galaxies, 12 of which reside more than 5 billion light-years from our planet.
One of the black holes stands out through its remoteness. This object lies 10.9 billion light-years away and is the most distant growing black hole ever discovered in a dwarf galaxy.
Another notable find is one of the dwarf galaxies itself — the least massive galaxy ever found to foster a growing black hole, notes NASA.
The black holes were picked up by Chandra after the observatory homed in on X-ray emissions coming from the center of the dwarf galaxies, “a telltale sign” that a black hole is lurking there, explains the space agency.
The astronomers believe that most of the 40 X-ray sources have a good chance of being IMBHs with masses ranging from 10,000 to 100,000 times that of the sun.
Study No. 2
As impressive as this discovery may be, another team managed to top it by finding a total of 305 IMBH candidates.
“This is the largest sample of intermediate mass black holes ever found,” said team leader Igor Chilingarian of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
This spectacular find is reported in The Astrophysical Journal and documents potential IMBHs located closer to Earth. Around 90 percent of these detections were made no more than 1.3 billion light-years away from our planet, while the most distant candidate was found about 2.8 billion light-years away.
A closer look with Chandra and the XMM-Newton at 10 of these candidates revealed that they weigh between 40,000 and 300,000 times the mass of the sun. Furthermore, these follow-up observations uncovered that nearly half of the 305 detections “are likely to be valid IMBHs,” notes the observatory.
“This black hole bounty can be used to address one of the biggest mysteries in astrophysics,” said Chilingarian.
Specifically, astronomers believe that IMBHs could play a big part in the formation of supermassive black holes, the mammoth black holes created during the early days of the universe.