I've been exploring this new ESA tool and I came across this structure.
What is it?
The circles look like they might be the footprint of a telescope. Perhaps there was a survey of this specific region of the sky with long exposures? Why was this part of the sky in particular observed with such detail? What exactly are we looking at here? What object(s) of interest lie here that justify observing in soft X-ray this small part of the sky in more detail than what surrounds it?