The supernova Cassiopeia A, as seen by the NuSTAR X-ray telescope (Image: DSS/JPL-Caltech/NASA) Two black holes, coloured magenta, spewing out X-rays in the outskirts of spiral galaxy IC 342 (Image: DSS/JPL-Caltech/NASA)

A space telescope has peered through dense dust and gas to produce the first images of the high-energy cosmos. These reveal two blazing black holes and a supernova remnant (see pictures, right).


The Nuclear Spectroscopic Telescope Array, or NuSTAR, was launched into Earth orbit on 13 June. It can detect X-ray radiation at energies between 6 and 79 kilo electronvolts, well above the range of NASA’s other orbiting telescopes, such as Chandra. Such high-energy radiation can penetrate gas and dust, so NuSTAR sees through the galactic debris that blinds other telescopes.

On 7 January, Fiona Harrison of the California Institute of Technology in Pasadena, released the telescope’s first images at a meeting of the American Astronomical Society in Long Beach, California.

One image (see picture, right) is of the supernova remnant Cassiopeia A, which is about 11,000 light years from us. It shows never-seen-before high-energy X-rays emitted from extremely hot regions and from particles accelerated to within a fraction of the speed of light by the supernova’s shock wave.

Bright black holes

NuSTAR also maps the emission of X-rays from the decay of radioactive elements such as titanium-44 in supernova remnants, which can tell us more about the exploding star that formed Cassiopeia A. “The distribution of this material is very sensitive to how the core of the star explodes,” Harrison says. “Is it a spherical explosion, is it lopsided, or is it asymmetric?”

She also released NuSTAR images of two astonishingly bright, ultra-luminous black holes (visible as magenta blobs in second image). They were caught spewing out X-rays in the outskirts of spiral galaxy IC 342, which lies 7 million light years away in the Camelopardalis constellation.

These are unlikely to be supermassive black holes, which are also luminous but are found near the centres of galaxies. Instead, they could be intermediate-size black holes a few thousand times the mass of our sun, or black holes that are guzzling matter from a companion star.

“These images have a combination of crispness and sensitivity that is orders of magnitude better than ever made before in this region of the electromagnetic spectrum,” says Harrison.