Page last updated Jul 20, 2012|
PGC 33423 (= Arp 148), Mayall's Object
A galactic collision in Ursa Major (RA 11 03 54.1, Dec +40 51 01)
A 15th-magnitude ring galaxy (type S pec) + A 15th-magnitude lenticular galaxy (type S0 pec)
A collision between two galaxies created the ring galaxy and peculiar galaxy apparently emerging from it collectively known as PGC 33423, or Arp 148. Based on a recessional velocity of 10350 km/sec, a straightforward calculation suggests that PGC 33423 is about 480 million light years away. However, for such distant objects we should take into account the expansin of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was almost 465 million light years away when the light by which we see it left it, 470 million years ago (the difference between the two numbers being due to the expansion of the intervening space during the light travel time). Given that and its apparent size of 0.6 by 0.4 arcmin, the pair extends across 80 thousand light years. The peculiar appearance of the galaxy was first noted by Nicholas U. Mayall in March 1940, whence its name.
Above, a 0.6 arcmin wide closeup of PGC 33423
(Image Credits: NASA, ESA, the Hubble Heritage Team (STScI/AURA)-ESA/Hubble Collaboration and A. Evans (University of Virginia, Charlottesville/NRAO/Stony Brook University), K. Noll (STScI), and J. Westphal (Caltech))
Below, a 2.4 arcmin wide region centered on the galactic collision
Below, a 12 arcmin wide region centered on the galactic collision
PGC 33487 (= Arp 21)
A 14th-magnitude spiral galaxy (type SBbc?) in Leo Minor (RA 11 04 59, Dec +30 01 38)
Based on recessional velocity of 8675 km/sec, about 390 million light years away. Given that and apparent size of 0.9 by 0.6 arcmin, about 100 thousand light years across.
Above, a 2.4 arcmin wide closeup of PGC 33487
Below, a 12 arcmin region centered on the galaxy