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| This new view of spiral galaxy IC 342, also known as Caldwell 5, includes data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. Image credit: NASA/JPL-Caltech/DSS |
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| This new view of the historical supernova remnant Cassiopeia A, located 11,000 light-years away, was taken by NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR. Image credit: NASA/JPL-Caltech/DSS |
NASA's
Nuclear Spectroscopic Telescope Array, or NuSTAR, set its X-ray eyes on a
spiral galaxy and caught the brilliant glow of two black holes lurking inside.
The
new image is being released Monday along with NuSTAR's view of the supernova
remnant Cassiopeia A, at the American Astronomical Society meeting in Long
Beach, Calif.
"These
new images showcase why NuSTAR is giving us an unprecedented look at the
cosmos," said Lou Kaluzienski, NuSTAR program scientist at NASA
headquarters in Washington. "With NuSTAR's greater sensitivity and imaging
capability, we're getting a wealth of new information on a wide array of cosmic
phenomena in the high-energy X-ray portion of the electromagnetic
spectrum."
Launched
last June, NuSTAR is the first orbiting telescope with the ability to focus
high-energy X-ray light. It can view objects in considerably greater detail
than previous missions operating at similar wavelengths. Since launch, the
NuSTAR team has been fine-tuning the telescope, which includes a mast the
length of a school bus connecting the mirrors and detectors.
The
mission has looked at a range of extreme, high-energy objects already,
including black holes near and far, and the incredibly dense cores of dead
stars. In addition, NuSTAR has begun black hole searches in the inner region of
the Milky Way galaxy and in distant galaxies in the universe.
Among
the telescope's targets is the spiral galaxy IC342, also known as Caldwell 5,
featured in one of the two new images. This galaxy lies 7 million light-years
away in the constellation Camelopardalis (the Giraffe). Previous X-ray
observations of the galaxy from NASA's Chandra X-ray Observatory revealed the
presence of two blinding black holes, called ultraluminous X-ray sources
(ULXs).
How
ULXs can shine so brilliantly is an ongoing mystery in astronomy. While these black
holes are not as powerful as the supermassive black hole at the hearts of
galaxies, they are more than 10 times brighter than the stellar-mass black
holes peppered among the stars in our own galaxy. Astronomers think ULXs could
be less common intermediate-mass black holes, with a few thousand times the
mass of our sun, or smaller stellar-mass black holes in an unusually bright
state. A third possibility is that these black holes don't fit neatly into
either category.
"High-energy
X-rays hold a key to unlocking the mystery surrounding these objects,"
said Fiona Harrison, NuSTAR principal investigator at the California Institute
of Technology in Pasadena. "Whether they are massive black holes, or there
is new physics in how they feed, the answer is going to be fascinating."
In
the image, the two bright spots that appear entangled in the arms of the IC342
galaxy are the black holes. High-energy X-ray light has been translated into
the color magenta, while the galaxy itself is shown in visible light.
"Before
NuSTAR, high-energy X-ray pictures of this galaxy and the two black holes would
be so fuzzy that everything would appear as one pixel," said Harrison.
The
second image features the well-known, historical supernova remnant Cassiopeia
A, located 11,000 light-years away in the constellation Cassiopeia. The color
blue indicates the highest-energy X-ray light seen by NuSTAR, while red and
green signify the lower end of NuSTAR's energy range. The blue region is where
the shock wave from the supernova blast is slamming into material surrounding
it, accelerating particles to nearly the speed of light. As the particles speed
up, they give off a type of light known as synchrotron radiation. NuSTAR will
be able to determine for the first time how energetic the particles are, and
address the mystery of what causes them to reach such great speeds.
"Cas
A is the poster child for studying how massive stars explode and also provides
us a clue to the origin of the high-energy particles, or cosmic rays, that we
see here on Earth," said Brian Grefenstette of Caltech, a lead researcher
on the observations. "With NuSTAR, we can study where, as well as how,
particles are accelerated to such ultra-relativistic energies in the remnant
left behind by the supernova explosion."
NuSTAR
is a Small Explorer mission led by Caltech and managed by NASA's Jet Propulsion
Laboratory in Pasadena for NASA's Science Mission Directorate in Washington.
Orbital Sciences Corporation of Dulles, Va., built the spacecraft. Its
instrument was built by a consortium including Caltech; JPL; the University of
California (UC) Berkeley; Columbia University; NASA's Goddard Space Flight
Center in Greenbelt, Md.; the Danish Technical University in Denmark; Lawrence
Livermore National Laboratory in Livermore, Calif.; and ATK Aerospace Systems
of Goleta, Calif.
NuSTAR's
mission operations center is at UC Berkeley, with the Italian Space Agency
providing an equatorial ground station located at Malindi, Kenya. The mission's
outreach program is based at Sonoma State University in Rohnert Park, Calif.
Goddard manages NASA's Explorer Program. Caltech manages JPL for NASA.
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