From the Chandra Blog, we learn today this image is "an intergalactic 'weather map' around the elliptical galaxy NGC 5813, the dominant central galaxy in a galaxy group located about 105 million light years away from Earth.
"Just like a weather map for a local forecast on Earth, the colored circle depicts variations in temperature across a region. This particular map presents the range of temperature in a region of space as observed by NASA's Chandra X-ray Observatory, with the hotter temperatures shown in red and decreasingly cooler temperatures shown in orange, yellow, green, and blue. The numbers displayed when rolling your mouse over the image give the gas temperature in millions of degrees". Explore more at the Chandra blog.
You're also invited to visit COLORING SPACE, a collaboration with Chandra X-Ray - a selection of images from my ORGANIVERSE Starry Night series of paintings in pointillism, juxtaposed with images from space.