Page last updated Dec 26, 2015|
A magnitude 17(?) galaxy (type S?) in Grus (RA 22 08 31.4, Dec -44 24 46)
Physical Information: Based on a recessional velocity of 21365 km/sec, a straightforward calculation indicates that PGC 122500 is about 995 million light years away. However, for objects at such distances we should take into account the expansion of the Universe during the time it took their light to reach us. Doing that shows that the galaxy was about 915 million light years away at the time the light by which we see it was emitted, about 945 to 950 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 about 0.2 by 0.2 arcmin, the galaxy is about 50 to 55 thousand light years across.
Above, a 12 arcmin wide DSS image centered on PGC 122500 (the dot above its label)
Below, a 0.6 arcmin wide DSS image of the galaxy