Celestial Atlas
PGC 57000 - 57499 ←     PGC Objects: PGC 57500 - 57999 Link for sharing this page on Facebook     → PGC 58000 - 58499
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Page last updated Jul 20, 2012

PGC 57678 (=
Arp 2)
A 13th-magnitude spiral galaxy (type SB(s)m) in Hercules (RA 16 16 18.3, Dec +47 02 44)

The 715 km/sec recessional velocity of PGC 57678 is too small to give a reliable redshift-based distance estimate, though the corresponding Hubble expansion distance of 35 million light years happens to be in reasonable agreement with a redshift-independent distance estimate of 50 million light years. Using the latter distance and its apparent size of 2.6 by 2.1 arcmin, PGC 57678 is about 40 thousand light years across. The galaxy is one of six chosen by Halton Arp for his Atlas of Peculiar Galaxies as an example of spiral galaxies of low surface brightness, hence its designation as Arp 2.

SDSS image of spiral galaxy PGC 57678, also known as Arp 2
Above, a 2.4 arcmin wide view of PGC 57678
Below, a 12 arcmin wide region centered on the galaxy
SDSS image of region near spiral galaxy PGC 57678, also known as Arp 2
Celestial Atlas
PGC 57000 - 57499 ←     PGC Objects: PGC 57500 - 57999     → PGC 58000 - 58499