From: LARRY KLAES (ljk4_at_msn.com)
Date: Wed Oct 10 2007 - 06:01:34 PDT
>From: "AAS Press Officer Dr. Steve Maran" <Steve.Maran_at_aas.org>
>To: "AAS Press Officer Dr. Steve Maran" <steve.maran_at_aas.org>
>Subject: JPL: Dust From Black Holes is Found
>Date: Tue, 9 Oct 2007 16:52:07 -0400
>
THE FOLLOWING RELEASE WAS RECEIVED FROM THE JET PROPULSION LABORATORY, IN
PASADENA, CALIFORNIA, AND IS FORWARDED FOR YOUR INFORMATION. (FORWARDING
DOES NOT IMPLY ENDORSEMENT BY THE AMERICAN ASTRONOMICAL SOCIETY.) Steve
Maran, American Astronomical Society steve.maran_at_aas.org 1-202-328-2010
x116
Contact:
Whitney Clavin
1-818-354-4673 Whitney.clavin_at_jpl.nasa.gov
NEWS RELEASE: 2007-114 Oct. 9, 2007
ASTRONOMERS FIND DUST IN THE WIND OF BLACK HOLES
The hit song that proclaimed, "All we are is dust in the wind," may have
some cosmic truth to it. New findings from NASA's Spitzer Space Telescope
suggest that space dust - the same stuff that makes up living creatures and
planets - was manufactured in large quantities in the winds of black holes
that populated our early universe.
The findings are a significant new clue in an unsolved mystery: where did
all the dust in the young universe originate?
"We were surprised to find what appears to be freshly made dust entrained in
the winds that blow away from supermassive black holes," said Ciska
Markwick-Kemper of the University of Manchester, U.K. Markwick-Kemper is
lead author of a new paper appearing in an upcoming issue of the
Astrophysical Journal Letters. "This could explain where the dust came from
that was needed to make the first generations of stars in the early
universe."
Space dust is essential to the formation of planets, stars, galaxies and
even life as we know it. The dust in our corner of the universe was piped
out by dying stars that were once a lot like our sun. But, when the universe
was less than a tenth of its present age of 13.7 billion years, sun-like
stars hadn't been around long enough to die and make dust. So, what produced
the precious substance back when the universe was just a toddler?
Theorists have long-postulated that short-lived, massive exploding stars, or
supernovae, might be the source of this mysterious dust, while others have
proposed that a type of energetic, growing supermassive black hole, called a
quasar, could be a contributing factor. A quasar consists of a supermassive
black hole surrounded by a dusty doughnut-shaped cloud that feeds it.
Theoretically, dust could form in the outer portion of the winds that slowly
blow away from this doughnut cloud.
"Quasars are like the Cookie Monster," said co-author Sarah Gallagher of the
University of California at Los Angeles, who is currently a visiting
astronomer at the University of Western Ontario, Canada. "They are messy
eaters, and they can consume less matter than they spit out in the form of
winds."
Nobody has found conclusive proof that either quasar winds or supernovae can
create enough dust to explain what is observed in the early universe.
Markwick-Kemper and her team decided to test the former theory and
investigate a quasar, called PG2112+059, located in the center of a galaxy
about 8 billion light-years way. Although this particular quasar is not
located in the early universe, because it is closer, it is an easier target
for addressing the question of whether quasars can make dust. The team used
Spitzer's infrared spectrograph instrument to split apart infrared light
from the quasar and look for signs of various minerals.
They found a mix of the ingredients that make up glass, sand, marble and
even rubies and sapphires. While the mineral constituting glass was
expected, the minerals for sand, marble and rubies were a surprise. Why?
These minerals are not typically detected floating around galaxies,
suggesting they could have been freshly formed in the winds rushing away
from the quasar.
For instance, the ingredient that makes up sand, crystalline silicate,
doesn't survive for long free-floating in space. Radiation from stars zaps
the minerals back to an amorphous, glass-like state. The presence of
crystalline silicate therefore suggests something - possibly the quasars
winds - is churning out the newly made substance.
Markwick-Kemper and her team say the case of the missing dust is not firmly
shut. They hope to study more quasars for further evidence of their
dust-making abilities. Also, according to the astronomers, quasars may not
be the only source of dust in the early universe. "Supernovae might have
been more important for creating dust in some environments, while quasars
were more important in others," said Markwick-Kemper. "For now, we are very
excited to have identified the different species of dust in a quasar
billions of light-years away."
Other authors of this paper include Dean Hines of the Space Science
Institute, Boulder, Colo., and Jeroen Bouwman of the Max Planck Institute
for Astronomy, Heidelberg, Germany. NASA's Jet Propulsion Laboratory,
Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's
Science Mission Directorate, Washington. Science operations are conducted at
the Spitzer Science Center at the California Institute of Technology, also
in Pasadena. Caltech manages JPL for NASA. Spitzer's infrared spectrograph
was built by Cornell University, Ithaca, N.Y. Its development was led by Jim
Houck of Cornell.
For graphics and more information about Spitzer, visit
http://www.spitzer.caltech.edu/spitzer and http://www.nasa.gov/spitzer .
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