MessageToEagle.com - NuSTAR (NASA's Nuclear Spectroscopic Telescope Array) is the first orbiting telescope with the ability
to focus high-energy X-ray light.
NuSTAR is kept busy looking at fascinating supernova remnants, galactic clusters and
giant black holes and incredibly dense cores of dead stars.
This time, it set its X-ray eyes on a spiral galaxy and caught the brilliant glow of two black holes lurking inside.
The impressive image is followed by NuSTAR's view of the supernova remnant Cassiopeia A. Both are presented at the American
Astronomical Society meeting in Long Beach, Calif.
Click on image to enlarge
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. Credit: NASA/JPL-Caltech/DSS
It can view objects in considerably greater detail than previous missions operating at similar wavelengths.
Since launch in June 2012, the NuSTAR team made several adjustments to the telescope, which includes a mast the length
of a school bus connecting the mirrors and detectors.
"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
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."
Click on image to enlarge
Sizzling Remains of a Dead Star
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. Blue indicates the highest energy X-ray light, where NuSTAR has made the first resolved image ever of this source. Red and green show the lower end of NuSTAR's energy range, which overlaps with NASA's high-resolution Chandra X-ray Observatory.
Light from the stellar explosion that created Cassiopeia A is thought to have reached Earth about 300 years ago, after traveling 11,000 years to get here. While the star is long dead, its remains are still bursting with action. The outer blue ring is where the shock wave from the supernova blast is slamming into surrounding material, whipping particles up to within a fraction of a percent of the speed of light. NuSTAR observations should help solve the riddle of how these particles are accelerated to such high energies
X-ray light with energies between 10 and 20 kiloelectron volts are blue; X-rays of 8 to 10 kiloelectron volts are green; and X-rays of 4.5 to 5.5 kiloelectron volts are red.
The starry background picture is from the Digitized Sky Survey.
Image credit: NASA/JPL-Caltech/DSS
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."