PASADENA, CALIF. — The most massive black hole yet
weighed lurks at the heart of the relatively nearby giant galaxy M87.
The
supermassive black
hole is two to three times heftier than previously thought, a new model
showed, weighing in at a whopping 6.4 billion times the mass of the sun. The
new measure suggests that other black holes in nearby large galaxies could also
be much heftier than current measurements suggest, and it could help astronomers
solve a longstanding puzzle about galaxy development.
"We
did not expect it at all," said team member Karl Gebhardt of the University of Texas at Austin.
The
discovery was announced here today at the 214th meeting of the American
Astronomical Society.
Game
changer
The finding
"is important for how black holes relate to galaxies," said team
member Jens Thomas of the Max Planck Institute for Extraterrestrial Physics in Germany. "If you change the mass of the black hole, you change how the black hole
relates to the galaxy."
Because of
this relationship, the revised mass could impact astronomers' theories of how
galaxies grow and form.
Higher
black hole masses could also solve a paradox of the masses of faraway,
developing galaxies called quasars.
These mysterious denizens of the early universe are very bright, developing
galaxies with black holes surrounded by gas and dust, all rife with star
formation. Quasars are colossal, around 10 billion solar masses, "but in
local galaxies, we never saw black holes that massive, not nearly,"
Gebhardt said.
"The
suspicion was before that the quasar masses were wrong," he said. But
"if we increase the mass of M87 two or three times, the problem almost
goes away."
Why M87
matters
M87 is 50 million light-years away. Nearly
three decades ago, it was
one of the first galaxies suggested to harbor a central black hole. Now
astronomers think that most large galaxies, including our own
Milky Way, have supermassive black holes at their centers.
M87 also has an
active jet shooting light out of the galaxy's core, created where matter
swirls closer to the black hole and approaches the speed of light, then
combines with tremendous magnetic fields. The spat-out material helps
astronomers understand how black holes attract and gobble up matter, a sloppy
process in which all is not consumed.
These
factors make M87 "the anchor for supermassive black hole studies,"
Gebhardt said.
While the
new mass of M87 is based on a model, recent observations from the Gemini North
Telescope in Hawaii and the European Southern Observatory's Very Large
Telescope in Chile support the model findings.
The study
of M87's mass will also be detailed later this summer in the journal Astrophysical
Journal.
advertisement
){kind=link}