Messier 77 is a galaxy in the constellation of Cetus, some 45 million light-years away from us. Also known as NGC 1068, it is one of the most famous and well-studied galaxies. It is a real star among galaxies, with more papers written about it than many other galaxies put together!
Despite its current fame and striking swirling appearance, the galaxy has been a victim of mistaken identity a couple of times; when it was initially discovered in 1780, the distinction between gas clouds and galaxies was not known, causing finder Pierre Mechain to miss its true nature and label it as a nebula. It was misclassified again when it was subsequently listed in the Messier Catalogue as a star cluster.
Now, however, it is firmly categorised as a barred spiral galaxy, with loosely wound arms and a relatively small central bulge. It is the closest and brightest example of a particular class of galaxies known as Seyfert galaxies -- galaxies that are full of hot, highly ionised gas that glows brightly, emitting intense radiation.
Strong radiation like this is known to come from the heart of Messier 77 -- caused by a very active black hole that is around 15 million times the mass of our Sun. Material is dragged towards this black hole and circles around it, heating up and glowing strongly. This region of a galaxy alone, although comparatively small, can be tens of thousands of times brighter than a typical galaxy.
Although no competition for the intense centre, Messier 77's spiral arms are also very bright regions. Dotted along each arm are knotty red clumps -- a signal that new stars are forming. These baby stars shine strongly, ionising nearby gas which then glows a deep red colour as seen in the image above. The dust lanes stretching across this image appear as a rusty, brown-red colour due to a phenomenon known as reddening; the dust absorbs more blue light than red light, enhancing its apparent redness.
ESA/Hubble Information Centre: http://www.spacetelescope.org
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
And made this stunning picture
A star-studded group of campaigners are promoting Asteroid Day to raise awareness of the threat of incoming rocks. Are we really facing imminent disaster?
An unmanned Vega rocket blasted off from French Guiana on Monday to put a sophisticated Earth-watching satellite into orbit, a European Space Agency webcast showed.
"It looks like we can finally include Venus in the small club of volcanically active solar system bodies," said an ESA scientist
A Canadian company put an HD camera on the ISS and got video so clear you can see cars driving past Boston's Fenway Park
Information it gathered is helping to improve climate models
Spacecraft to come within 180km of comet’s surface in attempt to improve contact signal and allow commands to be sent to the newly awakened lander
Housed under a dome located 8,000 feet above ground in a dormant Hawaii volcano
The ice world Tethys has had a very hard life, as a new image from the Cassini spacecraft shows.
Amazing what interns can do besides fetch coffee and make trips to the mail room