M100 Galaxy had a recent supernova SN 1979C. That now faint object is a strong X-ray source, so of course it is claimed to be a black hole.
On November 15, 2010 [31 years later] NASA announced that evidence of a black hole had been detected as a remnant of the supernova explosion.
One would expect the supernova would scatter its debris from the super explosion.
1) the remnant of a star, apparently having so much remaining mass, just gave up being a star and collapsed into a black hole.
2) while collapsing into this hole in space time(!), it also gathered up that far-flung debris field and,
3) compressed that debris into an accretion disk reaching a temperature having many, many zeroes,
4) to become bright in X-ray, but not in infrared,
5) within only 31 years.
That part of this story is just silly nonsense.
What is also interesting is the set of Chandra images in different wavelengths of M100 and its periphery.
Messier 100 (also known as NGC 4321) is a grand design intermediate spiral galaxy. Messier 100 is considered a starburst galaxy with the strongest star formation activity concentrated in its center, within a ring - actually two tightly wound spiral arms attached to a small nuclear bar with a radius of 1 kilo-parsec – where star formation has been taking place since at least 500 million years ago in separate bursts.
M100 is classified as type SAB(s)bc, not a Seyfert, though it is a starburst galaxy.
Seyfert galaxies are one of the two largest groups of active galaxies, along with quasars. They have quasar-like nuclei (very luminous, distant and bright sources of electromagnetic radiation) with very high surface brightnesses whose spectra reveal strong, high-ionisation emission lines, but unlike quasars, their host galaxies are clearly detectable.
Seyferts are like quasars and Arp found a consistent pairing of them.
If the spectrum were provided maybe we could help decide on the classification as Seyfert or not...
Here is the page with the Chandra images.
Clicking on the X-ray tab shows that wavelength image.
Moving the cursor over this image pops up the pointer to SN 1979C at the lower left.
I count about a dozen X-ray sources scattered about this "starburst" galaxy.
M100 is bursting with plasmoids!
Clicking on Infrared or Optical reveals the plasmoids dim away at longer wavelengths. Quasars are typically dimmed when shrouded in clouds of metallic ions so this observation suggests perhaps some are actually quasars. No spectra are provided to confirm this conclusion.
M100 follows the pattern of earlier posts (about M82 and M51) where an active spiral galaxy is surrounded by scattered X-ray sources (plasmoids not black holes).
One can only wonder what caused SN 1979c to brighten then dim in optical but remain bright in X-ray.
A quasar spectrum would certainly be interesting for any of the dozen, including the SN.
The Wikipedia topic does not mention whether anyone found an image with a star before this supernova.
a) the plasmoid arose at that spot, or
b) the plasmoid moved to there.
If (a) how?
if (b) how fast and why did it stop?
The same 2 questions apply to the other scattered X-ray sources below the galaxy. several sources are in the spiral arms and there is an opposing pair at 4 and 10 o'clock to the core, so this dozen has no clear pattern.
Finding a galaxy surrounded by plasmoids is tricky. A search for galaxies with black holes will find all galaxies!
I searched for Chandra M100 when I heard, in a new deepskyvideos, this SN was in a starburst galaxy and found M100 is like the other 2.
Having no spectra, one can only wonder if M100 actually ejected a quasar...