A newly found black hole in the center of a distant galaxy is giving scientists a bit of a headache because it's at least 30 times as big as current theories on the light-eating monsters should allow.
Compared to the mass of the galaxy it sits inside, the black hole has much more mass than was expected, many times what most theories of galactic evolution would consider possible, researchers in Britain say.
By measuring the movement of stars within the galaxy labeled SAGE0536AGN, astronomers at Keele University and the University of Central Lancashire determined the mass of the entire galaxy to be 25 billion times the mass of our sun.
The scientists also determined the mass of the black hole by measuring the light emitted by surrounding gas accelerated by the immense gravitational field of the black hole.
They arrived at the figure for its mass of 350 million solar masses: 30 times what would be expected for a galaxy of the measured size and mass.
"Galaxies have a vast mass, and so do the black holes in their cores. This one, though, is really too big for its boots—it simply shouldn't be possible for it to be so large," said Jacco van Loon, a Keele University astrophysicist and lead author of a study appearing in the Monthly Notices of the Royal Astronomical Society.
The title of the study [pdf] says it all: "An evolutionary missing link? A modest-mass early-type galaxy hosting an oversized nuclear black hole."
Current theories hold that the black hole in the center of a galaxy should grow—gain mass—at about the same rate as the galaxy grows.
In the case of SAGE0536AGN, the black hole has apparently grown much faster; either that, or the galaxy somehow prematurely stopped growing, the researchers suggest.
The galaxy, thought to be 9 billion years old, was initially discovered more or less by accident with NASA's Spitzer space telescope at infrared light wavelengths.
That suggests there may be more such mismatched galaxy/black holes to be discovered, which would constitute a whole new class of galaxies.
On the other hand, they acknowledge, SAGE0536AGN may be a one-off—a cosmic oddball.
