Last updated Dec 25, 2013
WORKING: (Need to add physical data for HCG objects)
PGC 50063 (= M101 = NGC 5457 = Arp 26)
A magnitude 7.9 spiral galaxy (type SAB(rs)cd) in Ursa Major (RA 14 03 12.4, Dec +54 20 58)
PGC 50123 (sometimes called HCG 70G)
A magnitude 15(?) spiral galaxy (type Sa? pec) in Canes Venatici (RA 14 04 00.0, Dec +33 19 54)
Sometimes considered part of Hickson Compact Group 70, even though not in Hickson's original paper. Based on a recessional velocity of 19010 km/sec, a straightforward calculation indicates that PGC 50123 is about 885 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 820 million light years away at the time the light by which we see it was emitted, almost 850 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 0.5 by 0.35 arcmin, the galaxy is about 120 thousand light years across. (As it happens, HCG 70 is actually two sets of galaxies, a trio consisting of HCG 70a, b and c (the larger galaxies at center and left of center), and a more than twice as distant quartet consisting of the other "members" of the Group (the four "smaller" galaxies, not really smaller but simply further away).)
Above, a 0.8 arcmin wide SDSS image of PGC 50123
Below, a 6.0 arcmin wide labeled SDSS image of HCG 70
PGC 50133 (= HCG 70F)
A magnitude 16(?) spiral galaxy (type SBbc?) in Canes Venatici (RA 14 04 04.3, Dec +33 19 45)
Based on a recessional velocity of 19245 km/sec, a straightforward calculation indicates that PGC 50133 is almost 900 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 830 million light years away at the time the light by which we see it was emitted, almost 860 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 0.3 by 0.2 arcmin, the galaxy is about 75 thousand light years across. (As it happens, HCG 70 is actually two sets of galaxies, a trio consisting of HCG 70a, b and c (the larger galaxies at center and left of center), and a more than twice as distant quartet consisting of the other "members" of the Group (the four "smaller" galaxies, not really smaller but simply further away).)
Above, a 0.6 arcmin wide SDSS image of PGC 50133
Below, a 6.0 arcmin wide labeled SDSS image of HCG 70
PGC 50134 (= IC 4369 = HCG 70E)
A magnitude 15.4 spiral galaxy (type Sbc?) in Canes Venatici (RA 14 04 05.9, Dec +33 19 14)
PGC 50138 (= IC 4370 = HCG 70D)
A magnitude 15.2 spiral galaxy (type Sc? pec) in Canes Venatici (RA 14 04 10.0, Dec +33 20 45)
PGC 50139 (= HCG 70A)
A magnitude 14(?) spiral galaxy (type Sa?) in Canes Venatici (RA 14 04 10.0, Dec +33 20 15)
As it happens, HCG 70 is actually two sets of galaxies, a trio consisting of HCG 70a, b and c (the larger galaxies at center and left of center), and a more than twice as distant quartet consisting of the other "members" of the Group (the four "smaller" galaxies, not really smaller but simply further away).
PGC 50140 (= IC 4371 = HCG 70B)
A magnitude 14.2 spiral galaxy (type S0(r)a? pec) in Canes Venatici (RA 14 04 10.9, Dec +33 18 27)
PGC 50159 (= HCG 70C)
A magnitude 15(?) spiral galaxy (type Sbc?) in Canes Venatici (RA 14 04 20.4, Dec +33 19 17)
As it happens, HCG 70 is actually two sets of galaxies, a trio consisting of HCG 70a, b and c (the larger galaxies at center and left of center), and a more than twice as distant quartet consisting of the other "members" of the Group (the four "smaller" galaxies, not really smaller but simply further away).
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