NICER Maps the X-ray Sky

NASA has just published a new map of the sky. It represents what we could see if our eyes were sensitive to x-rays. It was obtained thanks to the NICER instrument (“Neutron Star Interior Composition Explorer”) which has been performing measurements on board the International Space Station since June 2017.

The main mission of Nicer is to learn more about the inside of neutron stars, very compact and dense stars formed after the explosion of an end-of-life star. One of the objectives is to measure their diameter “with an accuracy of 5%”, says NASA.

To carry out these surveys, NICER scans the sky by moving from one target to another. It is these movements that are at the origin of the arcs that are visible on the final image.

A timelapse of NICER aboard the ISS.

If some curves appear brighter than others, it is only because the instrument has made the same path many times between specific targets. The curves intersect on bright points which are powerful sources of X-rays.

Among these sources can be found the Cygnus Loop, a supernova afterglow, or the MAXI J1820+070 source which is suspected to be actually a black hole.

By activating the NICER module in WinStars, you can replace the usual background of the sky with the image that NASA has just published on the mission site (it is also necessary to disable the Brunier module to display the image normally).

The original NASA annotations were deliberately left on the final image.

The map that NASA has just published as it appears in WinStars