Starve the black hole, and your galaxy dims. The photos below from Forbes show this amazing cosmic lesson firsthand!
Some large galaxies have a massive, active black hole as their source of light. These black holes are brighter than all other stars and have unique qualities. The photo below shows the active supermassive black hole in the Centarus A galaxy.
The intense outburst heats up and shocks the surrounding matter as the black hole devours matter. The image below shows a Hubble photo of an active, feeding black hole in the center of the NGC 1275 galaxy.
After the black hole stops feeding, some intense emission remains, even extending beyond the galaxy’s stars. The next photo shows bright emissions extending past the edge of the galaxies, evidence of prior AGN activity, although the black holes are too dim now.
Get the full story from Forbes and see a single galaxy brighten and fade in detail, from inactive to active to inactive again. Thank you x-rays, for giving us so much knowledge about space!