Object of the Week November 4, 2012 - Shakhbazian 166

Shakhbazian 166
Ursa Minor

RA
16 52 02

DEC
+81 36 23

Galaxy Chain of 10 galaxies

Mag 14.9+

Shakhbazian Compact Groups of Galaxies is a compilation ten list that totals 377 compact groups of galaxies found on the Palomar Sky Survey red charts. The survey was done between 1973 to 1979 by a Russian professional astronomer, Dr. Shakhbazian and his collaborators. Some have considered this list as the “next” Hickson Compact Galaxy group list…so if you have tackled that list, then this list is a good one to work on. ;)

Shakhbazian 166 is one of the brightest examples of this catalogue. It consists of 10 galaxies which most of them are in a nice chain of about 8’ long ranging from mag 14.9 to 16.5

A labelled DSS image is attached along with an eyepiece rendition taken from my 22" at 308x and 10.2' field.

Lastly, despite the RA suggesting a summer target, this is so close to the pole star it can be observed year round. It would be 9 degrees west of Polaris at sunset.


So remember next time you are out,

"GIVE IT A GO AND LET US KNOW"

Two questions:
Are the group members determined to be associated in terms of their own local proximity to each other (I would assume so).

Lastly what is the phonetic key to 'Shakhbazian' (just curious for this question)

Great Object and bright for a SHK.

Most people do not know that Shakhbazian is a woman. She is from Armenia and her name is Romelia K Shakhbazian.

Alvin,

thanks for the OOTW. Indeed one of the most beautiful SHK groups and from the member brightness also manageable with smaller aperture of perhaps 10"-12".

My sketch is with 27" and 419x under NELM 6m5+
Attachment 337
home

Quote:

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Originally Posted by Uwe Glahn

Alvin,

thanks for the OOTW. Indeed one of the most beautiful SHK groups and from the member brightness also manageable with smaller aperture of perhaps 10"-12".

My sketch is with 27" and 419x under NELM 6m5+
Attachment 337
home

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That aperture estimation is correct. A year ago (late Aug- early Sept '11) I took on the challenge of seeing if using my 12.5" scope I could observe 50 galaxies within 10º of Polaris. The answer was yes. On Sept 3 I observed this group. In fact I remember it being my favorite view of this 5 night observing project. In a single FOV at 456X I was able to make out 6 galaxies.

That whole observing project was so much fun.

Bill

Quote:

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Originally Posted by Marko

Lastly what is the phonetic key to 'Shakhbazian' (just curious for this question)

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Mark,

I'm not certain how others say it, but I pronounce it "Shock-baz-e-an"

and great object Alvin!!

Had two attempts on this group last night, both with my 18", from a mountain site (1300 meters amsl). My first attempt at 7pm was not so succesful, as the sky at the time was rather bright for the location (SQM 20.89), and the seeing anything but steady, not even allowing the use of 300x. I could see things in an arc coming and going, but the bloated images would not allow me to differentiate if they were indeed galaxies or not. Two hours later the conditions improved markedly (SQM 21.27) with considerably steadier seeing. Athough the group was lower (barely clearing the mountain ridge to the north by 5-6 degrees) I could easily hold steady with direct vision four galaxies, and many more were coming and going. With averted vision I could detect seven with certainty. I did not give it more time as the moonrise was about one hour away and wanted to check out a couple more targets, but it'on my "soon-to-sketch" list!

Shak 166 is Abell 2247 (aka the UGC 10638 group). It is on chart #4 of the second edition of Uranometria 2000. With my 20" dob, I usually see 8 galaxies.

Clear skies, glxytrios

Thanks All. I especially like groups that form a line and this has got to be a 'winner' in that respect with 8 all in a row. Now if we can just get some nice skies (winter starting here again).

A few nights ago, in 16" under SQM 21.3 skies, and 3/5 seeing, I could hold 3 galaxies reliably. Might have glimpsed one or two others. Nice target, thanks Alvin.

Nice Carter,

Do you know which ones you were able to see?

Shakhbazian 166 was definitely a highlight of my night of observing earlier this week. It was a fine night as summer nights go here. With my SQM-L I measured 21.58 mpsas in culminating Ursa Minor. At 225x, my 16” showed five members of this group. Three or four at a time could be held, and the arrangement in a chain meant that minimal eye movement was sufficient to see all five. The group was nicely framed by the 8-mm Ethos, and the view was very impressive.

The members of Shkh 166 were cataloged by Stoll, Tiersch, and Braun (STB) in 1996 (http://adsabs.harvard.edu/abs/1996AN....317..383S). They ordered the 11 members by visual magnitude, except that for some reason the places of #5 and #7 are reversed, i.e. #7 is actually the fifth brightest. It is not surprising that the five galaxies that I saw were STB 1-4 and 7, which range from Vm 14.88 to 15.42. After that it is a big jump to Vm 15.94 for STB 5 and then on through 17.81 for STB 11.

In the general galaxy catalogs, the 5 brightest are found in the MCG (+14-8-15 through -18), except STB 4, which is only found in the extended PGC as #2785443 (otherwise 2MASX J16521282+8137123).

On the chart in the OP and in the Faint Fuzzies guide to the Shakhbazian groups (an invaluable aid that made my observation possible), some labels seem to be misplaced. The following notes concern the 5 brightest members. “MCG+14-8-18” is correct. “PGC 59174” is by itself correct, but the MCG designation of this galaxy is +14-8-17 (which on the chart in question labels, incorrectly, a fainter galaxy farther E). “MCG+14-8-16” labels the non-MCG galaxy (PGC 2785443). “MCG+14-8-15” is actually -16. “PGC 59122” is by itself correct, but this galaxy is the real MCG+14-8-15.

When observing faint and rich galaxy groups I like to indicate galaxies and stars that are visible with arrowheads on a printed chart. This time I used the DSS-based chart from the Faint Fuzzies guide which is absolutely great. Now I scanned this field record and relabeled the galaxies (see last post). DSS acquires a certain visual realism when printed and then scanned on household equipment. Note that PGC 3099127 was not counted by Stoll, Tiersch, and Braun among the members of this group. Instead, the two very small unlabeled galaxies that are closer to MCG+14-8-16 (E and NW of it) were cataloged as members #10 and 11. Since these are Vm 17, I did not bother with identifications. I hope Alvin will forgive me such treatment of his chart – again, it was a great aid to me, I am just particular about identifications.

Attachment 693

A few weeks ago at the GSSP star party I made a serious attempt on Shakhbazian 166 with my 18" f/3.7 and just a 8mm SuperMono. It was very rewarding.

Was able to get convincing detection of 8 of the galaxies with the 9th being 3 distinct pops per minute for MAC 1651+8133 to the far SW. Of the 7 brightest members I felt PGC59174 was brightest with MCG+14-8-17, MCG+14-8-18,MCG+14-8-16,MCG+14-8-15 and PGC59122 were of similar brightness. PGC59120 was the dimmer of the 7 brightest members.

MAC 1651+8133 is not circled on my MegaStar chart but it looked fuzzy on my chart so I tried for it. As for the dimmer ones, I did not have Alvin's chart and missed MAC 1650+8134 due to it is not indicated in MegaStar chart so did not work on it. At the NE end of the chain just to the SW of MCG+14-8-17 I tried with no success on MAC 1653+8138. The tiny UGC 10638 just to the east of the mid-chain MCG +14-8-15 galaxy was detected only by being very convinced that there were two (or more) stellar points just East of MCG+14-8-15 (one of which SteveG told me was a star) but I was not able to state that I detected 3 or just two so I'll claim only two (they are so very close and dim)

Real fun group and thank Alvin for bringing it to the attention of the board.

Quote:

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Originally Posted by Jimi Lowrey

Great Object and bright for a SHK.

Most people do not know that Shakhbazian is a woman. She is from Armenia and her name is Romelia K Shakhbazian.

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Jimi, it's nice to find out details about astronomers like this, and nice to see another (somewhat rare) well-known astronomer who is a woman. The pronunciation of her name would be shakh-bahz-ee-YAHN (note that I am using 'kh' here to indicate a hard 'h' said far back in the mouth, kind of like as in the Greek 'chi' or Hebrew, etc. Stress is on the final syllable).

I am more or less fluent in Russian, and although the name is obviously Armenian, there are a lot of Armenians in Russia so I am familiar with the pronunciation of those names.