This new view of the historical supernova remnant Cassiopeia A, released… ( NASA/JPL-Caltech/DSS )
NASA’s NuSTAR X-ray telescope is providing fresh views of oddly bright black holes and breathtaking supernovae, scientists said Monday at the American Astronomical Society meeting in Long Beach.
NuSTAR mission scientists released high-energy X-ray images of two strangely bright black holes in the arms of spiral galaxy IC 342 about 7 million light years away and of Cassiopeia A, the shell of an exploded star, known as a supernova, just 11,000 light years away.
Since its launch last summer, the Nuclear Spectroscopic Telescope Array has been snapping shots at energies up to 79 kiloelectron volts – far beyond the roughly 10 KeV limit of other X-ray telescopes such as the Chandra X-Ray Observatory.
Higher resolution images from NuSTAR should help astronomers pin down why those two -- and other -- black holes shine more than 10 times brighter than is typical and should help them better understand what physical processes cause some of the particles around Cassiopeia A to reach such high speeds, said Caltech astrophysicist Fiona Harrison, the mission's principal investigator.
The new images released Monday are more than 100 times better than what previous telescopes could have delivered in that high-energy X-ray range, Harrison said.
“NuSTAR’s field of view is about the same size as a single pixel in previous orbiting high energy X-ray imagers,” Harrison said. Cassiopeia A, she said, “would appear as a single dot to those previous telescopes.”
High-energy X-rays can punch through dust and gas blocking our view into the distant universe, giving us a picture of what is otherwise concealed in the visible and infrared wavelengths. But that same property that makes them so useful also makes them difficult for to measure – the higher their energy, the harder they are to catch with a conventional telescope.
NuSTAR deals with this problem by using layers of advanced mirrors arranged at a glancing angle to the incoming X-ray light. Rather than facing the X-rays head-on – a losing proposition for the telescope – the mirrors bounce the rays into the detector about 30 feet away.
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