NASA will host a news teleconference at 10 a.m. PST (1 p.m. EST), Wednesday, Feb. 27, to announce black hole observations from its newest X-ray telescope, the Nuclear Spectroscopic Telescope Array (NuSTAR), and the European Space Agency's XMM-Newton X-ray telescope.
Visuals will be posted at the start of the teleconference on NASA's NuSTAR site http://www.nasa.gov/nustar.
Audio of the teleconference will be streamed live on NASA's website at: http://www.nasa.gov/newsaudio.
Audio and visuals will be streamed live online at: http://www.ustream.tv/nasajpl2
For more information about NuSTAR, visit: http://www.nasa.gov/nustar . For more information about the European Space Agency's XMM-Newton X-ray telescope, visit: http://www.esa.int/Our_Activities/Space_Science/XMM-Newton_overview.
Among the telescope's targets is the spiral galaxy IC342, also known as Caldwell 5, featured in one of the two new images (shown at top of the page). 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 (below)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. 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.
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.
"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."
The Daily Galaxy via NASA