It’s arduous to imagine, however Segue 1, a really faint dwarf galaxy, is on the centre of this picture
CDS, Strasbourg, France/CDS/Aladin
A close-by galaxy as soon as considered dominated by darkish matter appears to have a shock supermassive black gap at its centre. Segue 1 is barely a galaxy, with solely about 1000 stars in comparison with the Milky Manner’s a whole lot of billions, and but it seems to be residence to a black gap about 10 instances as huge as all its stars mixed.
Segue 1 and different comparable dwarf galaxies would not have sufficient stars to supply the gravity wanted to carry all of them collectively. To unravel that drawback, physicists have lengthy assumed they had been chock-full of the mysterious substance known as darkish matter, which we will’t see however that would generate the additional gravity.
So when Nathaniel Lujan on the College of Texas at San Antonio and his colleagues started testing laptop fashions of Segue 1, they anticipated the best-fitting mannequin could be one dominated by darkish matter. “I used to be working a whole lot of 1000’s of fashions, and I wasn’t discovering something that match,” says Lujan. “After which lastly I made a decision to mess with the black gap mass and unexpectedly it began to work.”
The mannequin that match greatest with our observations of Segue 1 included a black gap with a mass about 450,000 instances the mass of the solar. This was notably shocking not solely due to the galaxy’s lack of stars, but in addition due to its age – the few stars that it does have point out it fashioned solely about 400 million years after the very starting of star formation within the universe. That doesn’t go away a lot time to provide such a colossal black gap, particularly with the a lot bigger Milky Manner siphoning off a lot of the gasoline that would feed it from Segue 1 shortly after its beginning.
“This most likely signifies that there are extra supermassive black holes than we thought,” says Lujan. In that case, they may account for a few of the gravity that has till now been attributed to darkish matter – however we don’t but know if Segue 1 is consultant of all dwarf galaxies, so the hunt for extra supermassive black holes is on.
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