NuSTAR orbital X-ray telescope caught two mysterious black holes

A special new view of spiral galaxy IC 342 showing two unusually radiant black holes was made possible by NASA's new X-ray telescope NuSTAR, standing for Nuclear Spectroscopic Telescope Array. The high-energy X-ray data from NuSTAR have been translated to the color magenta, and superimposed on a visible-light view highlighting the galaxy and its star-studded arms.

Launched last June, NuSTAR is the first orbiting telescope with the capability to focus high-energy X-ray light. It is now possible to analyze objects in considerably greater detail than with previous tools operating at similar wavelengths.

"These new images showcase why NuSTAR is giving us an unprecedented look at the cosmos," said Lou Kaluzienski, NuSTAR program scientist at NASA headquarters in Washington. "With NuSTAR's greater sensitivity and imaging capability, we're getting a wealth of new information on a wide array of cosmic phenomena in the high-energy X-ray portion of the electromagnetic spectrum."

The mission has looked at a range of extreme, high-energy objects in the X-ray range until now, which especially includes black holes, as well as the incredibly dense cores of dead stars. NuSTAR is utilized to search for black holes in far away galaxies, but also in the core region of our Milky Way galaxy.

The two radiant black holes, marked in magenta on the image, were first detected at lower-energy X-ray wavelengths by NASA's Chandra X-ray Observatory. With NuSTAR's complementary data, astronomers can start to home in on the black holes' mysterious properties. The black holes appear much brighter than typical stellar-mass black holes, such as those that pepper our own galaxy, yet they cannot be supermassive black holes or they would have sunk to the galaxy's center. Instead, they may be intermediate in mass, or there may be something else going on to explain their extremely energetic state. These so-called ultraluminous X-ray sources (ULXs) are an ongoing mystery, since it is unexplained how they can radiate on the massive scale observed - a puzzle that NuSTAR is hoped to help in solving.

IC 342 lies 7 million light-years away in the Camelopardalis constellation.