This artist's concept shows the most distant supermassive black hole
ever discovered. It is part of a quasar from just 690 million years
after the Big Bang. Credit: Robin Dienel/Carnegie Institution for
Science. › Larger view
Scientists have uncovered a rare relic from
the early universe: the farthest known supermassive black hole. This
matter-eating beast is 800 million times the mass of our Sun, which is
astonishingly large for its young age. Researchers report the find in the
journal Nature.
"This black hole grew far larger than we
expected in only 690 million years after the Big Bang, which challenges our
theories about how black holes form," said study co-author Daniel Stern of NASA's Jet Propulsion
Laboratory in Pasadena, California.
Astronomers combined data from NASA's Wide-field Infrared Survey
Explorer (WISE) with ground-based surveys to identify potential distant objects
to study, then followed up with Carnegie Observatories' Magellan telescopes in
Chile. Carnegie astronomer Eduardo Bañados led the effort to identify candidates out of the hundreds of
millions of objects WISE found that would be worthy of follow-up with Magellan.
For black holes to become so large in the
early universe, astronomers speculate there must have been special conditions
to allow rapid growth -- but the underlying reason remains mysterious.
The newly found black hole is voraciously
devouring material at the center of a galaxy -- a phenomenon called a quasar.
This quasar is especially interesting because it comes from a time when the
universe was just beginning to emerge from its dark ages. The discovery will
provide fundamental information about the universe when it was only 5 percent
of its current age.
"Quasars are among the brightest and most
distant known celestial objects and are crucial to understanding the early
universe," said co-author Bram Venemans of the Max Planck Institute for
Astronomy in Germany.
The universe began in a hot soup of particles
that rapidly spread apart in a period called inflation. About 400,000 years
after the Big Bang, these particles cooled and coalesced into neutral hydrogen gas.
But the universe stayed dark, without any luminous sources, until gravity
condensed matter into the first stars and galaxies. The energy released by
these ancient galaxies caused the neutral hydrogen to get excited and ionize,
or lose an electron. The gas has remained in that state since that time. Once
the universe became reionzed, photons could travel freely throughout space.
This is the point at which the universe became transparent to light.
Much of the hydrogen
surrounding the newly discovered quasar is neutral. That means the quasar is
not only the most distant -- it is also the only example we have that can be
seen before the universe became reionized.
"It was the universe's last major transition
and one of the current frontiers of astrophysics," Bañados said.
The quasar's distance is
determined by what's called its redshift, a measurement of how much the
wavelength of its light is stretched by the expansion of the universe before
reaching Earth. The higher the redshift, the greater the distance, and the
farther back astronomers are looking in time when they observe the object. This
newly discovered quasar has a redshift of 7.54, based on the detection of
ionized carbon emissions from the galaxy that hosts the massive black hole.
That means it took more than 13 billion years for the light from the quasar to
reach us.
Scientists predict the sky contains between 20
and 100 quasars as bright and as distant as this quasar. Astronomers look
forward to the European Space Agency's Euclid mission, which has significant
NASA participation, and NASA's Wide-field Infrared Survey Telescope (WFIRST)
mission, to find more such distant objects.
"Withseveral
next-generation, even-more-sensitive facilities currentlybeing built, we can
expect many exciting discoveries in the very earlyuniverse in the coming
years," Stern said.
Caltech in Pasadena, California, manages JPL
for NASA.
News Media Contact
Elizabeth Landau
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-6425
elizabeth.landau@jpl.nasa.gov
Eduardo Bañados
Carnegie Observatories, Pasadena, Calif.
626-304-0236
ebanados@carnegiescience.edu
Source: NASA/News
