A Tour of Galaxy Chains

What dynamic is it that lines up groups of galaxies into long, sinuous chains? Or is it chance alone that welds together these so beautiful patterns in the eyepiece? Our tour of galaxy chains runs from the big, relatively bright and well-known (Pisces Group, Abell 194) to the tiny, faint and obscure (Hickson 55, Shakhbazian 49). Along the way, you will get a look at some nice bright NGC galaxies near our more challenging targets. If you have any favorite galaxy chains, send me your observing notes.

Burbidge's Chain MCG-4-3-10
00 47 35 -20 25 44
Pisces Group NGC 383 Group, Arp 331
01 07 25 +32 24 47
Abell 194 NGC 541
01 25 44 -01 22 42
Abell 539 UGC 3274, VV 161
05 16 37 +06 26 27
Shakhbazian 049 anon
10 15 15 +38 54 56
Hickson 55 Arp 329, UGC 6514
11 32 07 +70 48 56
Hickson 56 Arp 322, UGC 6527
11 32 37 +52 56 52
Shakhbazian 016 Arp 330
16 49 06 +53 25 00
Shakhbazian 166 UGC 10638
16 54 45 +80 35 30

Our tour begins in Pisces, about three degrees south of Beta Andromedae. The Pisces Group is a pretty chain of half a dozen 13th and 14th magnitude galaxies that should look good in modest-sized scopes. The Pisces Group is a member of the Perseus - Pisces Supercluster, one of the largest known structures in the universe. Even at a distance of 250 million light years, this chain of galaxy clusters extends more than 40 degrees across the winter sky!

Burbidge's Chain is an interesting string of four MCG galaxies lying only 18 arcminutes north-northeast of NGC 247, a giant member of the nearby Sculptor Group. NGC 247 itself is ninth magnitude but of very low surface brightness, which can make it tough to spot in a small scope. The northernmost and southernmost members of the chain were relatively easy to pick up in my 17.5" scope.

Two galaxy chains from the Abell Catalog of Rich Clusters of Galaxies are next on our tour. Abell 194 in Cetus includes nine NGC galaxies brighter than 15th magnitude lined up north and south across a 30 arcminute field. The brightest members, at 13th magnitude, are NGC 541 and an interesting double galaxy, NGC 545/547. Deep photography shows a faint bridge connecting these galaxies, in which is imbedded a famous peculiar galaxy known as Minkowski's Object, probably not observable in amateur scopes. (Let me know if you have seen it.) The next target, Abell 539 in Orion, is centered around UGC 3274, a 14th-magnitude galaxy chain about 2.5 degrees west of Bellatrix. An impressive sight in a 17.5" scope, the chain extends north-south with three or four bright knots visible. These clusters are about 300 million light years away.

Our next two galaxy chains are from the Hickson Atlas of Compact Groups of Galaxies. The first, Hickson 55 in Draco, is an extremely compact string of five interacting galaxies located 25 arcminutes northwest of 12th-magnitude NGC 3735. Use high power and look for several tiny knots in a common envelope, like peas in a pod. Another remarkable chain of galaxies, Hickson 56 in Ursa Major, is found just seven arcminutes south of the beautiful 10th-magnitude barred spiral NGC 3718. Like me, you may have observed NGC 3718 without even noticing the tiny galaxy chain in the same field!

Our tour concludes with three galaxy chains from the little-known Shakhbazian (Shkh) Catalog of Compact Groups of Galaxies. The history of the Shkh catalog began in 1957, when Romela Shakhbazian discovered a remarkable group of 12 faint nearly-stellar objects. Initially thought to be an association of stars, subsequent investigations revealed it to be a member-rich compact group of luminous red elliptical galaxies at a redshift distance of nearly 1.5 billion light years!

Galaxies in Shakhbazian groups are mostly compact gas-poor ellipticals and lenticulars. In the eyepiece, they are nearly-stellar objects with high surface brightnesses. You will need high power and good finder charts to distinguish them from faint field stars. They are themselves arranged in very compact groups. All but a handful of the 377 Shkh groups are probably beyond the range of visual observation in all but the largest amateur scopes.

One of the best and brightest is Shakhbazian 166 in Ursa Minor. Steve Gottlieb and I were able to pick up five of the 11 members strung out over less than ten arcminutes. Andreas Domenico calls our next target, Shakhbazian 016 in Draco, the most beautiful Shakhbazian group by far, but we found it pretty tough going with our 17.5" scopes. I could pick up three members with averted vision. With great persistence Steve managed to glimpse a couple more.

The last galaxy chain in our tour, Shakhbazian 049 in Leo Minor, has reportedly been observed in telescopes as small as 12 inches, but the best I could do was an occasional, vague suspicion that there was something there in the right spot. This tiny chain lies just to the east of an 11th magnitude star and only 20 arcminutes northwest of the NGC 3158 galaxy group, a clump of eight bright NGC galaxies, so you will enjoy your visit to Leo Minor even if you fail to spot this extremely difficult galaxy chain.