Largest spiral galaxy

Largest spiral galaxy in known universe

January 14, 2013

Spiral galaxy NGC 6872 combines visible light images from the European Southern Observatory’s Very Large Telescope with far-ultraviolet data from NASA’s GALEX and 3.6-micron infrared data acquired by NASA’s Spitzer Space Telescope (credit: NASA’s Goddard Space Flight Center/ESO/JPL-Caltech/DSS)

Astronomers have crowned the spectacular barred spiral galaxy NGC 6872 the largest-known spiral galaxy in the known universe, based on archival data from NASA’s Galaxy Evolution Explorer (GALEX) mission, on loan to the California Institute of Technology,

By analyzing the distribution of energy by wavelength, the team uncovered a distinct pattern of stellar age along the galaxy’s two prominent spiral arms. The youngest stars appear in the far end of the northwestern arm, within the tidal dwarf candidate, and stellar ages skew progressively older toward the galaxy’s center.

The team found no sign of recent star formation along the bar, which indicates it formed at least a few billion years ago.

“Understanding the structure and dynamics of nearby interacting systems like this one brings us a step closer to placing these events into their proper cosmological context, paving the way to decoding what we find in younger, more distant systems,” said team member and Goddard astrophysicist Eli Dwek.