Chandra Release - August 5, 2021

Visual Description: V404 Cygni

This composite image features a series of incomplete concentric rings in a black field dotted with gleaming white, yellow, and golden stars.
 

The giant rings are light echoes, a phenomenon similar to echoes from sound waves bouncing off of hard surfaces. These light echoes were produced when X-rays burst from gas near a black hole at the center of the image and bounced off of cosmic dust clouds. Black holes themselves, like this one in the V404 Cygni binary system, are invisible.

 
Here, the X-rays are rendered as hazy neon blue rings. The smallest, near the center, is the brightest and the most substantial. The remaining concentric rings are somewhat wispier, but are much larger, and extend beyond the edges of the image. These rings are not clearly defined like the clean ridges on a record album. Instead, they appear vague and blurred, resembling curving tire marks left in wet snow.   

 
The rings are incomplete, with gaps at our upper right, and upper left. A string of gaps appear in a horizontal line across the middle of the image, as if portions of the neon blue X-ray rings were removed with a straight swipe of an eraser. These gaps show the edges of Chandra's field of view during the observations, or the sections of the field Chandra did not observe.