This diagram shows how the diameter of the 17-billion-solar-mass giant 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. Image credit: D. Benningfield/K. Gebhardt/StarDate
This boundary is called the “event horizon,” the point from beyond which, once crossed, neither matter nor light can return.
A picture of galaxy NGC 1277 taken with Hubble Space Telescope which contains the immense black hole containing as much mass as 17 billion suns. The black hole makes up an enormous 14% of the galaxy’s mass.
Astronomers have used the Hobby-Eberly Telescope at The University of Texas at Austin’s McDonald Observatory to measure the mass of what may be the most massive black hole yet — 17 billion Suns — in galaxy NGC 1277. The unusual black hole makes up 14 percent of its galaxy’s mass, rather than the usual 0.1 percent. This galaxy and several more in the same study could change theories of how black holes and galaxies form and evolve. The work will appear in the journal Natureon Nov. 29.
NGC 1277 lies 220 million light-years away in the constellation Perseus. 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,” said team member Karl Gebhardt of The University of Texas at Austin. “It’s almost all black hole. This could be the first object in a new class of galaxy-black hole systems.” 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 (in astronomical jargon, a “lenticular galaxy”).
The find comes out of the Hobby-Eberly Telescope Massive Galaxy Survey (MGS). 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 Nature lead author Remco van den Bosch, who began this work while holding the W.J. McDonald postdoctoral fellowship at The University of Texas at Austin. He is now at the Max Planck Institute for Astronomy in Heidelberg, Germany.