A new telescope designed to peer into the twisted X-ray Universe has just returned its first imaging data.
The Imaging X-Ray Polarimetry Explorer (IXPE), a NASA-Italy Space Agency collaboration, focused its attention on one of the Milky Way’s most famous explosions: Cassiopeia A.
Located 11,000 light-years away, it’s the expanding remnant of a star thought to have been observed exploding in the 1690s, and it’s one of the most well-studied objects in the Milky Way, for good reason – it has provided some invaluable insight into supernovae.
Cassiopeia A emits light with a variety of wavelengths, including radio, optical, and, of course, X-rays. In fact, Cassiopeia A was also the first science image from another of NASA’s X-ray observatories, Chandra.
But IXPE is showing us the object in a way we haven’t seen before.
“The IXPE image of Cassiopeia A is as historic as the Chandra image of the same supernova remnant,” says astronomer and IXPE principal investigator Martin C. Weisskopf of NASA’s Marshall Space Flight Center.
“It demonstrates IXPE’s potential to gain new, never-before-seen information about Cassiopeia A, which is under analysis right now.”
In the image above, the saturation of the magenta color corresponds to the intensity of X-ray light observed by IXPE. It overlays high energy X-ray data, shown in blue, from NASA’s Chandra X-Ray Observatory. Chandra and IXPE, with different kinds of detectors, capture different levels of angular resolution, or sharpness. An additional version of this image is available showing only IXPE data. These images contain IXPE data collected from Jan. 11 to 18.
There’s a lot going on in Cassiopeia A. Before it died, the precursor star was a massive object that became unstable as it ran out of fuel, ejecting its outer layers to form a cloud of circumstellar material. As a result, when the supernova finally occurred, the shock wave did not enter pristine space, but rather a relatively dense cloud.
The shocks and magnetic fields produced by this intense environment can generate synchrotrons, which accelerate electrons and produce high-energy X-rays.
A key measurement that scientists will make with IXPE is called polarization, a way of looking at how X-ray light is oriented as it travels through space. The polarization of light contains clues to the environment where the light originated. IXPE’s instruments also measure the energy, the time of arrival, and the position in the sky of the X-rays from cosmic sources.
IXPE will use Cassiopeia A polarization data to show scientists for the first time how the amount of polarization varies across the supernova remnant, which is about 10 light-years in diameter. Researchers are currently working with the data to create the object’s first-ever X-ray polarization map. This will provide new information about how X-rays are generated at Cassiopeia A.
“IXPE’s future polarization images should unveil the mechanisms at the heart of this famous cosmic accelerator,” said Roger Romani, an IXPE co-investigator at Stanford University. “To fill in some of those details, we’ve developed a way to make IXPE’s measurements even more precise using machine learning techniques. We’re looking forward to what we’ll find as we analyze all the data.”
IXPE was launched from Cape Canaveral on a Falcon 9 rocket and is now orbiting 370 miles (600 kilometers) above Earth’s equator. The mission is a partnership between NASA and the Italian Space Agency, with partners and scientists from 12 countries. Ball Aerospace, based in Broomfield, Colorado, is in charge of spacecraft operations.
READ MORE: NASA’s New X-ray Mission Will Reveal the Secrets of Extreme Cosmic Objects (video)