Trent Perrotto
Headquarters, Washington
202-358-0321
trent.j.perrotto@nasa.gov
Lynn Chandler
Goddard Space Flight Center, Greenbelt, Md.
301-286-2806
lynn.chandler-1@nasa.gov
RELEASE: 11-158
RADIO TELESCOPES CAPTURE BEST-EVER SNAPSHOT OF BLACK HOLE JETS
WASHINGTON -- An international team, including NASA-funded
researchers, using radio telescopes located throughout the Southern
Hemisphere has produced the most detailed image of particle jets
erupting from a supermassive black hole in a nearby galaxy.
"These jets arise as infalling matter approaches the black hole, but
we don't yet know the details of how they form and maintain
themselves," said Cornelia Mueller, the study's lead author and a
doctoral student at the University of Erlangen-Nuremberg in Germany.
The new image shows a region less than 4.2 light-years across -- less
than the distance between our sun and the nearest star.
Radio-emitting features as small as 15 light-days can be seen, making
this the highest-resolution view of galactic jets ever made. The
study will appear in the June issue of Astronomy and Astrophysics and
is available online.
Mueller and her team targeted Centaurus A (Cen A), a nearby galaxy
with a supermassive black hole weighing 55 million times the sun's
mass. Also known as NGC 5128, Cen A is located about 12 million
light-years away in the constellation Centaurus and is one of the
first celestial radio sources identified with a galaxy.
Seen in radio waves, Cen A is one of the biggest and brightest objects
in the sky, nearly 20 times the apparent size of a full moon. This is
because the visible galaxy lies nestled between a pair of giant
radio-emitting lobes, each nearly a million light-years long.
These lobes are filled with matter streaming from particle jets near
the galaxy's central black hole. Astronomers estimate that matter
near the base of these jets races outward at about one-third the
speed of light.
Using an intercontinental array of nine radio telescopes, researchers
for the TANAMI (Tracking Active Galactic Nuclei with Austral
Milliarcsecond Interferometry) project were able to effectively zoom
into the galaxy's innermost realm.
"Advanced computer techniques allow us to combine data from the
individual telescopes to yield images with the sharpness of a single
giant telescope, one nearly as large as Earth itself," said Roopesh
Ojha at NASA's Goddard Space Flight Center in Greenbelt, Md.
The enormous energy output of galaxies like Cen A comes from gas
falling toward a black hole weighing millions of times the sun's
mass. Through processes not fully understood, some of this infalling
matter is ejected in opposing jets at a substantial fraction of the
speed of light. Detailed views of the jet's structure will help
astronomers determine how they form.
The jets strongly interact with surrounding gas, at times possibly
changing a galaxy's rate of star formation. Jets play an important
but poorly understood role in the formation and evolution of
galaxies. NASA's Fermi Gamma-ray Space Telescope has detected much
higher-energy radiation from Cen A's central region.
"This radiation is billions of times more energetic than the radio
waves we detect, and exactly where it originates remains a mystery,"
said Matthias Kadler at the University of Wuerzburg in Germany and a
collaborator of Ojha. "With TANAMI, we hope to probe the galaxy's
innermost depths to find out."
Ojha is funded through a Fermi investigation on multiwavelength
studies of Active Galactic Nuclei.
The astronomers credit continuing improvements in the Australian Long
Baseline Array (LBA) with TANAMI's enormously increased image quality
and resolution. The project augments the LBA with telescopes in South
Africa, Chile and Antarctica to explore the brightest galactic jets
in the southern sky.
NASA's Fermi Gamma-ray Space Telescope is an astrophysics and particle
physics partnership, developed in collaboration with the U.S.
Department of Energy, along with important contributions from
academic institutions and partners in France, Germany, Italy, Japan,
Sweden and the U.S. The Australia Long Baseline Array is part of the
Australia Telescope National Facility, which is funded by the
Commonwealth of Australia for operation as a National Facility
managed by the Commonwealth Scientific and Industrial Research
Organization.
For more information and images, visit:
http://www.nasa.gov/topics/universe/features/radio-particle-jets.html
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