NASA's NuSTAR Catches Black Holes in Galaxy Web

Jan. 7, 2013

J.D. Harrington
Headquarters, Washington
202-358-5241
j.d.harrington@nasa.gov

Whitney Clavin
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-4673
whitney.clavin@jpl.nasa.gov

RELEASE: 13-007

NASA'S NUSTAR CATCHES BLACK HOLES IN GALAXY WEB

WASHINGTON -- 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."

For more information about NuSTAR and to view the new images, visit:

http://www.nasa.gov/nustar


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