Washington, Nov 29:
Astronomers claim to have discovered the most massive black hole ever
known in a small galaxy about 250 million light-years from Earth,
holding a mass equivalent to 17 billion Suns.
The super-massive black hole is located inside the galaxy NGC 1277 in the constellation Perseus.
This diagram shows how the diamater of the 17-billion-solar-mass black
hole in the heart of galaxy NGC 1277 compares with the orbit of Neptune
around the Sun. The black hole is eleven times wider than Neptune's
orbit. Shown here in two dimensions, the "edge" of the black hole is
actually a sphere. This boundary is called the "event horizon," the
point from beyond which, once crossed, neither matter nor light can
return.
It makes up about 14 per cent of its host galaxy’s mass, compared with
the 0.1 per cent a normal black hole would represent, Scientists said,
adding that it has a mass equivalent to 17 billion Suns.
This galaxy and several more in the same study could change theories of how black holes and galaxies form and evolve.
The galaxy is only ten percent the size and mass of our own Milky Way.
Despite NGC 1277’s diminutive size, the black hole at its heart is more
than 11 times as wide as Neptune’s orbit around the Sun.
“This is a really oddball galaxy. It’s almost all black hole. This could
be the first object in a new class of galaxy-black hole systems,” said
team member Karl Gebhardt of The University of Texas at Austin.
Furthermore, the most massive black holes have been seen in giant blobby
galaxies called “ellipticals,” but this one is seen in a relatively
small lens-shaped galaxy.
The study’s endgame is to better understand how black holes and galaxies
form and grow together, a process that isn’t well understood.
“At the moment there are three completely different mechanisms that all
claim to explain the link between black hole mass and host galaxies’
properties. We do not understand yet which of these theories is best,”
said lead author Remco van den Bosch in a statement.
The problem is lack of data. Astronomers know the mass of fewer than 100
black holes in galaxies. But measuring black hole masses is difficult
and time-consuming.
So the team developed the Hobby-Eberly Telescope Massive Galaxy Survey
to winnow down the number of galaxies that would be interesting to
follow up on.
The team has studied 700 of their 800 galaxies with the telescope.
“The mass of this black hole is much higher than expected,” Gebhardt
said, “It leads us to think that very massive galaxies have a different
physical process in how their black holes grow”.
The study was published in the journal Nature.
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