Page last updated Jul 22, 2012
PGC 9103
A 16th-magnitude galaxy (type S?) in Cetus (RA 02 23 50.7, Dec -04 37 05)
Based on a recessional velocity of 2275 km/sec, PGC 9103 is about 105 million light years away. Given that and its apparent size of 0.7 by 0.5 arcmin, it is about 20 thousand light years across. Note: As in many cases, a Wikisky search for PGC 9103 truncates to PGC 103, which is the wrong galaxy. Use its coordinates to view the correct object. |
Above, a 2.4 arcmin wide closeup of PGC 9103
Below, a 12 arcmin wide region centered on the galaxy, also showing PGC 9107 and 9113
PGC 9107 (with PGC 9113 = Arp 54)
A 16th-magnitude galaxy (type S?) in Cetus (RA 02 23 59.2, Dec -04 41 48)
Apparent size 0.45 by 0.3; nothing else available, but presumed to be interacting with PGC 9113 (which see for images), in which case it would be about 575 million light years away and about 75 thousand light years across. Note: As in many cases, a Wikisky search for PGC 9107 truncates to PGC 107, which is the wrong galaxy. Search for Arp 54 or use its coordinates to view the correct object. |
PGC 9113 (with PGC 9107 = Arp 54)
A 14th-magnitude spiral galaxy (type SAbc) in Cetus (RA 02 24 02.6, Dec -04 41 35)
With PGC 9107, an Arp Atlas example of a spiral galaxy with a small bright companion. Based on a recessional velocity of 12990 km/sec, a straightforward calculation indicates that PGC 9113 is about 600 million light years away. However, for objects at such distances we should take into account the Universal expansion during the time it took their light to reach us. Doing that shows that the galaxy was about 575 million light years away when the light by which we see it was emitted, just under 590 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 the galaxy's apparent size of 1.0 by 0.5 arcmin, PGC 9113 is about 160 thousand light years across. Note: As in many cases, a Wikisky search for PGC 9113 truncates to PGC 113, which is the wrong galaxy. Search for Arp 54 or use its coordinates to view the correct object. PGC 9113 (and presumably 9107), and nearby galaxies PGC 1053379, 1054270 and 3080366 all have similar recessional velocities (and presumably, distances). As a result, they may be a gravitationally bound group. |
Above, a 2.4 arcmin wide closeup of PGC 9107 and 9113
Below, a 12 arcmin wide region centered on the pair
Below, the same image also showing labels for PGC Objects 9103, 1053379, 1054270 and 1054693
PGC 9463 (= ESO 198-13)
A 13th-magnitude spiral galaxy (type (R')SA(r)ab?) in Eridanus (RA 02 29 16.1, Dec -48 29 29)
Based on a recessional velocity of 5450 km/sec, PGC 9463 is about 250 million light years away. Given that and its apparent size of 1.7 by 1.2 arcmin, it is about 125 thousand light years across. Used by the de Vaucouleurs Atlas of Galaxy Types as an example of galaxy type (R)SA(r)ab. |
Above, a 2.4 arcmin wide closeup of PGC 9463
Below, a 12 arcmin wide region centered on the galaxy
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