THE VLT GOES TO WORK ON SPIRAL GALAXY NGC 3621
Image Credit: European Southern Observatory (ESO), Very Large Telescope (VLT). CLICK photo for larger view and look below for information and links.
Located 22 million light years away, far beyond the “local group” in the constellation Hydra is the bright and beautiful spiral galaxy of NGC 3621. This galaxy is an almost ordinary spiral galaxy with its telltale bright blue spiral arms of star formation and permeating those arms are thick lanes of dust and gas to be used as future generations of star systems. What you don’t see here is the typical central bulge and yellow hue to the core which indicates ancient stars that have migrated to the nucleus of the galaxy over the timeline of its life. It is however an active Seyfert 2 galaxy which indicates a supermassive black hole with an estimated mass of around 20,000 solar masses. That’s unusual because almost all of the active galactic nuclei observed are surrounded by a central bulge of ancient stars. When a galaxy with those traits is discovered; they’re classified as “pure-disk galaxies.”
There’s another interesting fact that this galaxy hides within it. Around the nucleus of the galaxy but orbiting out further than the supermassive black hole are two smaller black holes each with a mass of a few thousand solar masses. That brings the total black hole count in this galaxies nucleus to three. The likely outcome here is that the two smaller black holes will actually end up merging with the central one, adding to its mass.
Some of the brighter stars in this galaxy have been used as “standard candles” which help astronomers determine distance to the galaxy as well as help create a detailed map of the universe. The extremely bright orange/yellow stars in this image are foreground stars of the Milky Way.
NAME?: NGC 3621.
WHAT IS IT?: Spiral Galaxy.
HOW FAR AWAY IS IT?: Approximately 22 million light years.
HOW BIG IS IT?: Roughly 95,000 light years in diameter.
APPARENT MAGNITUDE: 10 or +10.
WHERE IS IT? (General): Constellation Hydra the sea serpent/snake and the largest of the 88 constellations.
WHERE IS IT? (Exact RA/Dec J2000): RA 11h 18m 16.52s / DEC –32° 48′ 50.7″.
European Southern Observatory (ESO) page for this photo: http://www.eso.org/public/images/potw1148a/
SIMBAD data page for NGC 3621: http://simbad.u-strasbg.fr/simbad/sim-id?Ident=NGC+3621