Starship Asterisk*

Here's a comparison of visible light with the X-ray emission: https://www.researchgate.net/figure/51893319_fig3_Figure-11-Top-panel-surface-brightness-and-temperature-maps-to-the-north-Lower The X-ray image is thermal emission from the hot plasma which fills up most of a galaxy cluster. It has temp...

Here's a comparison of visible light with the X-ray emission: https://www.researchgate.net/figure/51893319_fig3_Figure-11-Top-panel-surface-brightness-and-temperature-maps-to-the-north-Lower The X-ray image is thermal emission from the hot plasma which fills up most of a galaxy cluster. It has tempe...

It's not an either-or thing. It's both fact and artifact, and it takes a trained eye to interpret. Yes - there is noise. It gives rise to some of the wiggly lines in the output image (see paper). The number of photons in the input image isn't massive, so we can only apply this to deep observations ...

The algorithm and image are described in our paper: https://arxiv.org/abs/1605.02911 It basically measures the gradient of the image on various scales using a Gaussian gradient magnitude filter. This filter convolves the image with the gradient of a Gaussian (i.e. normal) function, in X and Y, then ...