NASA’s Hubble Telescope has developed a type of late, it seems, primarily capturing spiral galaxies throughout May. These two are particularly fantastic.
The majority of galaxies in our local universe are irregular or spiral. What’s pretty special about that is how unique each one is, particularly the latter.
Over the weekend, NASA’s Hubble programme produced its second spiral galaxy image of the month, with the pair showing just how different these galaxies can be.
NGC 6814, a spiral galaxy that probably hosts a supermassive black hole, image via ESA/Hubble & NASA
Called NGC 6814, this ‘face-on’ image flattens out the galaxy, with a luminous nucleus, “spectacular sweeping arms” and dark dust rippled throughout.
NASA says this galaxy enjoys a particularly bright nucleus, which is probably why this image is so clearly estimated – the brightness is a “telltale sign that the galaxy is a Seyfert galaxy”.
Seyfert galaxies have particularly active cores, emitting powerful bursts of radiation. So much X-ray radiation comes from NGC 6814 that astronomers estimate a supermassive black hole (18m times the size of our sun) rests in the centre.
The blue stars you can see are the result of a newly-created burst of stars along regions of ionised gas.
NGC 4394 was discovered in 1784 by the German–British astronomer William Herschel, image via ESA/Hubble & NASA
Earlier this month, NGC 4394 was also captured by Hubble, and is similarly thought to host a supermassive black hole. This is because there’s no other source of energy that scientists can spot, despite plenty of recently-created blue stars.
“In the case of NGC 4394, it is likely that gravitational interaction with a nearby neighbour has caused gas to flow into the galaxy’s central region, providing a new reservoir of material to fuel the black hole or to make new stars.”
