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For context, those images are from the paper about the event: https://iopscience.iop.org/article/10.3847/1538-4357/ac3f3a
The top image is figure 2:
Pre-explosion PS1/YSE stacked griz-band template (top), detection (middle), and difference (bottom) images of progenitor precursor emission preceding SN 2020tlf. Stacked images were created from 13 z-band, 45 i-band, 23 r-band, and 22 g-band pre-explosion observations spanning a phase range of δ t = −169.7 to −3.7 days since first light (MJD 58929-59095). The PS1 g band is not detected.
So the top row is pre-explosion, and the middle row is the detection of the supernova. The bottom row is the mathematic difference between the two images.
The bottom image is figure 1 and should be straightforward.
It took a little digging to find out what the different bands correspond to in familiar terms: https://astronomy.stackexchange.com/questions/18986/what-is-the-ugriz-magnitude-system
And here's a page with the electromagnetic spectrum in angstroms: http://www.e-missions.net/ssa/CH2-friendandfoe.htm
So we're looking at mostly infrared imagery, I think. I expect that due to expansion of the universe, it's red-shifted, so if you were local it would more in the visible spectrum. Incidentally, this is exactly the kind of thing that the JWST is equipped to image. It would have been nice to have it fully operational, but such is life.
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