Yale University researchers have found what they believe to be three young supermassive black holes in a distant, still emerging galaxy. The discovery raises the possibility that this type of black hole continues to form billions of years after the Big Bang, challenging current theory. |
Astronomers at Yale University
have discovered what appear to be three fast-growing supermassive black holes
in a relatively young, still-forming galaxy.
The discovery raises the possibility that
this type of black hole continues to form billions of years after the Big Bang,
challenging current theory. Astronomers previously thought all supermassive
black holes emerged soon after the birth of the universe 13.7 billion years
ago.
“As far as the host galaxy is concerned,
these just popped into existence,” says Kevin Schawinski, a postdoctoral fellow
at the Yale Center for Astronomy and Astrophysics
and the lead author of a paper published online in Astrophysical Journal Letters. “They’re feeding on material about
as fast as they can.”
Black holes are points in space where
matter is packed so densely that light itself cannot escape. Standard black
holes fall within a narrow mass range, and can exist anywhere within a galaxy.
Supermassive black holes have far greater masses, which can vary widely, and
they exist only at the centers of galaxies. Every galaxy is thought to have a
supermassive black hole at its center, including ours, the Milky Way.
Astronomers believe that standard black
holes form when the center of a giant star collapses inward. But the formation
of supermassive black holes is largely a mystery, one the recent Yale discovery
could help illuminate.
“We’re seeing a direct clue about where and
when supermassive black holes can come into being,” Schawinski says.
Using observations and data collected
through the Hubble Space Telescope, his research team identified the three
suspected supermassive black holes in a distant, still-emerging galaxy where
conditions, including abundant gas and young stars, are ripe for their formation.
The galaxy exists at a point in space that is 4.8 billion years after the Big
Bang—or, in Earth time, nearly nine billion years ago. (In far outer space,
distance and time are essentially the same, so seeing into deep space is like
looking back in time.) Relative to the galaxy, the three black holes are
roughly 100 million years old, Schawinski says.
Several clues suggest that the newly
discovered supermassive black holes are young: their small size for their type;
the extreme rarity of finding three together; and their fast rate of growth.
Further observations are necessary in order to confirm that they are
supermassive black holes, the scientists note.
The astronomers’ discovery meanwhile raises
questions about how supermassive black holes could form so long after the Big
Bang, and whether this happens in many galaxies or was a freak occurrence.
“Kevin
mined the Hubble archive to find this really stunning case where fragments of a
galaxy appear to have collapsed into three rapidly growing black holes,” says
co-author Meg Urry, director of the Yale
Center for Astronomy and
Astrophysics and chair of Yale’s physics department. “This offers an entirely
new view of how supermassive black holes might grow within their host
galaxies.”
