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Shakhbazian Compact Galaxy Groups Observing Notes



    In 1957, Romela Shakhbazian examined a Palomar Sky Atlas plate and noticed a tight group of red objects. She examined more plates and found 16 more such groups and all were about 1’ in diameter, so she wrote a journal article on it. It was thought of at the time as a small tight cluster of red stars. It wasn’t until 15 years later in 1972, when Robinson and Wampler took a closer look and a spectrum of five objects in the first listed group that Shakhbazian looked at and realized that they were not red stars, but galaxies.  They named it Shakhbazian 1 to represent a new system of galaxies called compact clusters of compact galaxies. 

    In 1973, several others took a new systematical search to look for more compact clusters of compact galaxies on the Palomar Sky Survey. The following criterion must be met to be considered for the new system of galaxies:
1.    Consists of 5 to 15 members.
2.    Each galaxy’s apparent magnitude is between 14th to 19th magnitude.
3.    Compact group. Relative distances of member galaxies should be 3/5 of the diameter of a galaxy.
4.    Almost all must be extremely red. No more than two blue galaxies.
5.    Galaxies must be compact. High surface brightness, and not diffuse.
6.    The group must be isolated.

    It turned out that one of the richest groups was the first one, Shakhbazian 1. The spectra of the five objects in Shakhbazian 1 calculated the distance to be about 2 billion light years distant with a diameter of 620,000 light years across and the average diameter of individual galaxies was just 40,000 light years across. In comparison, the Milky Way and Andromeda Galaxy were about 100,000 and 130,000 light years across respectively, and 2.2 million light years from each other. It was also found that the absolute magnitude of the brightest member of Shakhbazian 1 is -23.0, which means that it is one of the brightest known galaxies. The velocity dispersion is very low, suggesting that they are together in one compact group. Imagine what that would look like for the deep sky observer from one of hte member galaxies! 5+ high luminosity galaxies crammed into a "small" 620,000 light year space.


   Then in 1975 Mirzoyan, Miller, and Osterbeck took a closer look at Shakhbazian 123 and determined that it has similar characteristics to Shakhbazian 1. They thought they were onto something. Further research on other Shakhbazian groups showed that the pattern of small velocity dispersion properties was indeterminate.

    After research from 1972 to 1979, it was demonstrated that most Shakhbazian groups are in one of the following types of groups:
1.    Spherical concentrated groups
2.    Chains
3.    Peripheric groups

    Later observations of these groups with high angular resolution revealed that member galaxies are mostly of E and S0 types. This can be helpful for visual observers as it was detectable even at 2 billion light years distant. Also, it has now been shown that the group members are not particularly compact, so the more recent journal articles now call them Shakhbazian Compact Galaxy Groups (Shk).


   By 1979, the catalogue grew to 377 and was compiled by Shakhbazian, Petrosian, Baier, and Tiersch. They produced 10 journal articles. The unfortunate thing was that the coordinates of the groups in the original journal articles given were relatively low accuracy, so more than a few of the Shk groups were difficult to discern in galaxy-rich fields. The good news, almost 20 years later, D. Stoll and team put out ten papers on the photometry and the identification of each member of the groups. I have used his papers to center and mark the members in this observing report. It also turned out that because of the quality of the Palomar plates, some members were faint red stars, not galaxies.
  

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Since this is a very challenging list, here are some observing tips that will enhance your ability to see them:

  • A steady sky is key for resolving individual members.
  • Take great care when looking. Stars appear brighter in the eyepiece than the stars on the DSS and SDSS images and gives false positives. Examine the provided annotated images and note the locations of the foreground stars.
  • Keep your eyes dark adapted as fully as possible. Even the sky glow from the sky, especially if the Milky Way is above the horizon, can impact your night vision. When not looking at the eyepiece, waiting for your turn at the eyepiece, or just taking a break, look down at the dark ground, preferably with a hood over your head. I sometimes look down for a few minutes before looking in the eyepiece.
  • To further darken the field around you, use a hooded vest.  The hood should block all extraneous light, including the sky glow and even the Milky Way at very dark sites.
  • Use your eyepiece guards. They offer an extra light blocking barrier between your eyepiece and your eye.  If your eyepiece doesn’t come with one, you can install one for some eyepiece. Click here for some ideas.
  • If you think you saw the object(s), but are not sure, gently tap the telescope or wiggle it.  The stars will wiggle in the eyepiece, and if you saw the object, it would wiggle as well along with the foreground stars.
  • If you are tired, you won't see as much. Take a nap or rest. Try to observe in a comfortable position. It helps if you aren't straining your neck (or anything else) when you are trying to observe.  Some fleeting objects would disappear when fatigued.
  • Use high magnification, such as 300x or even higher.  When I observe objects from this list, I generally use my 6mm ZAO-II, 5mm BGO, and/or 4mm ZAO-II orthoscopic eyepieces in my 22”. I employ the TMB 1.8x ED Barlow if I need even more magnification.
  • Use low-glass count and high transmission eyepieces. Even with modern glass polish and coating technology, there is still a very small, but noticeable difference between high glass count eyepieces, such as the common wide-field eyepiece versus a simple Orthoscopic or Plφssl.  Over the years, I’ve done many comparisons between various eyepieces, such as the Naglers, Ethos, Naglers, Pentax XW’s, Orthoscopics (Zeiss, Baader, University Optics, etc.), and Plφssl (some makes) and found that low glass count eyepieces consistently outperform high glass count eyepieces.  See Observing Tips, titled Going DEEP with simple eyepieces, for more information.


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This page contains my personal observations of the Shakhbazian Compact Galaxy Groups.


Only galaxies seen are marked.  The numbering scheme used in the images are consistent with D. Stoll's papers.

The idea of this page is to encourage those with large reflectors to give this catalogue a shot. This group is considered the "next" Hickson Groups. All require a large telescope to see the groups. An experienced observer should be able to see what I saw.


Telescopes used:

  • 22" f/4 reflector
  • 30" f/4.3 reflector
  • 48" f/4 reflector



When you look through the eyepiece, just imagine what you are really looking at...an isolated distant compact group of galaxies that is not close to any other galaxies.  Not only that, these compact groups contain mostly very luminous galaxies packed in a small space, averaging less than a third the distance between the Milky Way and the Andromeda Galaxy.  Each galaxy is even more luminous than the Andromeda Galaxy.  Just think about it, if we lived in one of the stars in one of those galaxies, there would be several to over 20 very bright naked eye galaxies scattered throughout the sky.


As I observe more Shakhbazian Compact Galaxy Groups, I'll add them here.




Shakhbazian 1

48” @ 488x – 8 galaxies detected. The group is 1.1’ in diameter.

1 and 2 were immediately picked up as a bright close double galaxy. 1 is slightly larger round glow than 2 with a brighter center and diffuse edges. 2 is round with a much brighter center with more defined edges than 1.

3 and 6 are considerably faint round glows with somewhat brighter centers. Both are about the same size.

4 and 5 are faint, very small and round.

9 is
very faint, very small round glow.  7 and 8 are not resolved and appears as a very faint small round glow.


Shk3
Shakhbazian 3

48” @ 488x – Very faint unresolved diffuse glow. Could not pick out individual members.



Shk5
Shakhbazian 5

30” @ 538, 754 and 1256x - I picked up two of the five members at 754 and 1256x. 
Component 1 (PGC 34447) and Component 5 (PGC 34452) were seen as a bipolar elongated patch.  Not quite resolved.
Component 4 (PGC 34453) was suspected as an extremely faint patch attached to PGC 34452.  The position angle of 1 (PGC 34447) and 5 (PGC 34452) is directly E/W.  1 (PGC 34447) was about 10” from a magnitude 16 star.  Component 2 (PGC 34444) and Component 3 (PGC 34448) were not seen.

48” @ 488 and 610x – The seeing wasn’t that steady while I was at the eyepiece.  I’ve seen all five components at an earlier time with this scope, but unfortunately could not locate my notes.  Detected only components 1, 3 and 5 as very to extremely faint very small round glows.  A mag 16.7 star lies just 20” SW from component 1.


Shakhbazian 6

48” @ 488 and 813x - Nice group of five very faint very small round glows forming a backward “L”.  The long end is 0.9’ long and the short is 0.2’ long.  Component 2, MAC 1118+5144A, is a fairly faint small amorphous even surface brightness glow.  1 was not seen.




Shakhbazian 9

48” @ 488x – A total of 7 galaxies seen in a chain with one off the west side.  A faint double star lies just 9” west of the brightest galaxy, component 1.  All are faint to very faint small round glows.  A blazing mag 8.1 star lies 4.5’ SW from component 7.


Shakhbazian 11

48” @ 488 and 610x – Seven galaxies detected as faint to very faint small round glows.  A faint star is just 10” east of component 2.  A very faint star is just 10” NE of component 8.




Shakhbazian 13

22” @ 328, 383, and 460x – The west member “1” is a faint 2:1 elongated glow with diffuse edges.

A very faint trio of stars, roughly a 45-degree right triangle, are north and to the east. An extremely faint galaxy “9” seen to the east.




Shakhbazian 16 

22” @ 203, 293, 377 and 528x

Five galaxies are chained in a rough N-S line and almost equally spaced. From top to bottom are MCG+9-27-95, -96, -94, -92 and -91. They are roughly 45” to 60” apart. A 8.7 magnitude star lies just 1.2’ ESE of the top member.

MCG+9-27-95 – Very faint, extremely small round patch. About 10” across and even surface brightness. A 16th magnitude star lies about 20” NE

MCG+9-27-96 – Very faint, extremely small round patch. About 10” across and even surface brightness.

MCG+9-27-94 – Considerably faint, very small round patch of about 20” diameter. It has a gradually brightening center.

MCG+9-27-92 – Considerably faint, very small round patch. About 15” diameter

and even surface brightness throughout.

MCG+9-27-91 – Considerably faint, very small round patch, with a very slightly

brighter center. About 20” across.

MAC 1649+5322A – not seen



Shakhbazian 19 

22” @ 306 and 460x - This was observed at the Texas Star Party under NELM 7.2 skies. The unresolved group appeared as an extremely faint slightly elongated glow.

PA = 90° and less than 10” across. The star to the north was not detected.

 

30” @ 542x – The glow is a 2:1 elongated unresolved glow. PA = 90.  The star was detected and brighter than the unresolved glow.

 

48” @ 813x – Galaxies 1, 4 and 5 - Appeared as three distinct nuclei immediately detected.  Galaxy 2 – a thin glow with a nearly stellar core with PA = 150.



Shakhbazian 21

22” @ 383, 460 and 591x – Three galaxies detected. 

1 – very faint, very small round even surface brightness glow. 

2 – very faint small round glow with a stellar core. 

4 – extremely faint very small round glow.



Shakhbazian 22

48” @ 488x and 610x – Total of five galaxies seen. 

Component 4 is a fairly faint small round glow with component 5 just off the west edge. 

The other three components; 1, 2 and 3, are faint small round glows.



Shakhbazian 30

22” @ 203, 377 and 528x

At 377x, this nice group shows four bright members and one small faint elliptical.  A 11th magnitude star is in the mix of this group that fits in a circle about 5 arc-minutes in diameter.

Component 1 (IC 5357) – This dominant elliptical is a very bright, 2:1 elongated oval with a brighter center with a position angle of 140˚.  Averted vision shows a little more up to 90”.  An 11.2 magnitude star lies 2’ SE.

Component  5 (IC 5359) – Faint and very thin streak lying about 4’ ESE of IC 5357.  No sign of a nucleus was visible.  The position angle is about 135˚ and 75” long and about 10” thick.  More magnification did not improve the view of this edge-on spiral galaxy.

Component  3 (IC 5356) – Bright and 2:1 elongated patch.  Even surface brightness with a brighter core.  PA = 45 and is 45” long.  This member lies 3’ due south of IC 5357.  A pair of 15th magnitude stars lie 45” south.

Component  2 (IC 5351) – This very small galaxy has a very dominant nucleus.  Bumping it to 528x, the extension grew by about 20”.  This small elliptical lies 1’ SW of IC 5357.

Component  4 (PGC 72405) – Very small faint round smudge about 1’ NW of IC 5357.  Less than 10” in diameter.

Shakhbazian 35

22” @ 383, 460 and 591x – total of four members seen. 

The brightest one, 1, is the “right angle” of a 30-60-right triangle. Faint round even surface brightness glow.

Component 2 at the “60-degree” angle and component 3 at the “30-degree angle” appear as very faint round even surface brightness glows.

Component 4, is an extremely faint very small round glow is between 1 and 3.



Shakhbazian 38

22” @ 383x – Unresolved mass, even surface brightness thin glow.  PA = 60° and 0.5 x 0.1’ in size.  A 15.8 mag star lies 0.4’ SE from the center.



Shakhbazian 40

22” @ 383x – One considerably bright round glow with defined edges in the middle with a bunch of faint to extremely faint galaxies surrounding it.  I didn’t mark each member, but there are at least 15 galaxies up to 5’ from the center galaxy.



Shakhbazian 44

22” at 328, 383, 460 and 591x – Four members detected.  Starting from the south end. 

2 – very faint round small glow. 
5 – extremely faint, very small round glow with an extremely faint star just west. 
1 – extremely faint round glow with diffuse edges. 
10 – very faint very small round glow. (Now not sure if I saw the star or the galaxy.)



Shakhbazian 49

22” @ 383, 460 and 591x – two extremely faint, very small round faint glows seen about 30” apart. PA = 20



Shakhbazian 53

22” @ 383 and 460x – Just 5 members seen.  All are very faint to extremely faint.  See photo.  I should have increased the magnification higher.



Shakhbazian 54

22” @ 383 and 460x – A bright foreground star interferes with the observation of this group.  Need to use a narrow field eyepiece and keep it off the field.  With it in the field, I could see only 1 or 2 galaxies.  With it off the field, six galaxies are seen.  All are very to extremely faint small glows.



















Shakhbazian 60

48” @ 488x - Seven galaxies seen in a rough crescent arrangement with the cusp pointed to the west.  2’ long from N to S and 1.2’ wide.  Component 1 is the brightest of the bunch with a very faint nearly stellar companion that is barely resolved on the SSE edge.  Component 4 was detected as a nearly stellar galaxy while component 3 is a 2:1 even surface brightness glow.  PA = 135 and 0.1’ long.  The rest are very faint very small round glows and all are <0.1’ across.


Shakhbazian 63 

48” @ 375 and 488x – 3 members seen forming an equilateral triangle with each side being 0.5’ across.  Actually, the two double galaxies were not resolved, the west pair is a very faint soft round glow, and the SW pair is an extremely faint round glow. 



Shakhbazian 79

48” @ 488x – Not much was seen but an unresolved glow.



Shakhbazian 81 

22” @ 306 and 460x – Very faint unresolved clump.  It sits closest to the SW star of the equilateral triangle.



Shakhbazian 84

22” @ 306 and 460x – 2 extremely faint glows detected with averted vision.  Component 2 lies just 34” north of component 1.  A 14.2 magnitude star lies 45” SSW from the southern galaxy.



Shakhbazian 98

48” @ 488, 610 and 813x – A curved chain of seven faint galaxies (marked as 2 to 9), which seven are nearly stellar.  I didn’t detect the galaxy labeled as “9”.  “1” is just off the SE edge of NGC 2675.  “J”, a non-member, is the brightest of the very small stellar galaxies and lies about 45” east of the upper middle part of the chain.  A 13.0 mag star lies 30” east from the center of the chain.  Nearby galaxy, NGC 2675 is a very bright slightly elongated glow with diffuse edges and a much brighter small core.

Note: Most of the “objects” are faint stars, but the chain is still cool to observe.



Shakhbazian 154

48” @ 488x – 9 members detected.  Ranging from considerably bright to extremely faint.

 

9 is considerably 2:1 elongated glow with a stellar core and defined edges.

1, 2, 3 and 4 are equal in brightness while 1 is a little larger than the other three. They are a little fainter than 9, round with brighter center and somewhat diffuse edges.

Galaxies 7 and 8 are slightly fainter than 1 to 4. All are round and have even surface brightness.

10 is very faint, very small round glow.

5 is extremely faint very small round glow.