Blazing Black Holes Spotted in Spiral Beauty
This
new view of spiral galaxy IC 342, also known as Caldwell 5, includes
data from NASA's Nuclear Spectroscopic Telescope Array, or NuSTAR.
High-energy X-ray data from NuSTAR have been translated to the color
magenta, and superimposed on a visible-light view highlighting the
galaxy and its star-studded arms. NuSTAR is the first orbiting telescope
to take focused pictures of the cosmos in high-energy X-ray light;
previous observations of this same galaxy taken at similar wavelengths
blurred the entire object into one pixel.
The two magenta spots
are blazing black holes first detected at lower-energy X-ray
wavelengths by NASA's Chandra X-ray Observatory. With NuSTAR's
complementary data, astronomers can start to home in on the black holes'
mysterious properties. The black holes appear much brighter than
typical stellar-mass black holes, such as those that pepper our own
galaxy, yet they cannot be supermassive black holes or they would have
sunk to the galaxy’s center. Instead, they may be intermediate in mass,
or there may be something else going on to explain their extremely
energetic state. NuSTAR will help solve this puzzle.
IC 342
lies 7 million light-years away in the Camelopardalis constellation. The
outer edges of the galaxy cannot be seen in this view.
This image shows NuSTAR X-ray data taken at 10 to 35 kiloelectron volts.
The visible-light image is from the Digitized Sky Survey.
› NuSTAR data only Image credit: NASA/JPL-Caltech/DSS
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:
NASA
Guillermo Gonzalo Sánchez Achutegui
ayabaca@gmail.com
ayabaca@hotmailcom
ayabaca@yahoo.com
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