New Delhi:
US space agency NASA’s NuSTAR space observatory recently captured stunning illuminated sources of X-ray light. This happened after the rays appeared and disappeared in NGC 6946 which is a galaxy that resembles colourful fireworks. A new study, published in the Astrophysical Journal, offers some possible explanations for the surprise appearance of the green source near the center of the galaxy, which came into view and disappeared in a matter of weeks.
The primary objective of the NuSTAR observations was to study the supernova — the explosion of a star much more massive than our Sun — that appears as a bright blue-green spot at upper right. 
(Photo Credits: NASA/JPL-Caltech)
"Ten days is a really short amount of time for such a bright object to appear," said Hannah Earnshaw, a postdoctoral researcher at Caltech in Pasadena, California, and lead author on the new study. "Usually with NuSTAR, we observe more gradual changes over time, and we don't often observe a source multiple times in quick succession. In this instance, we were fortunate to catch a source changing extremely quickly, which is very exciting."
According to NASA: “the new study explores the possibility that the light came from a black hole consuming another object, such as a star. If an object gets too close to a black hole, gravity can pull that object apart, bringing the debris into a close orbit around the black hole. Material at the inner edge of this newly formed disk starts moving so fast that it heats up to millions of degrees and radiates X-rays. (The surface of the Sun, by comparison, is about 10,000 degrees Fahrenheit, or 5,500 degrees Celsius.)”
