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II Zw 174 aka NGC 7241 A galaxy with blue "orbs".

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#1 Rick J

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Posted 27 April 2013 - 02:20 PM

II Zw 174/NGC 7241 is a very strange edge on galaxy in Pegasus about 50 million light-years from us by redshift. The CGPG says of it: "Edge-on spiral, tremendous absorption lane and various large blue compact patches." I'd say that sums it up rather well. It has little central bulge so is rather flat. Not flat enough to make the Flat Galaxy Catalog but it is in the 2MASS version of IR strong flat galaxies (2MFGC 16794). Their flatness requirements are not as strict. The core is very strange with those blue blobs (star clusters I assume) floating around. They remind me of a neighbor who keeps seeing dust "orbs" in her flash photos and thinks they are ghosts of her deceased husband, a daughter and her pet dogs and cats. She's known around here as "The crazy lady down the way." She actually hires a medium to "communicate" with them.

It's companion UGC 11964 is a featureless flat galaxy that did make the FGC as entry 2379. It too is about 50 million light-years away by redshift so a true companion. While I'd like to blame the oddities of II Zw 174 on interaction with it, it is so featureless I can't see that there's ever been any interaction. More likely the odd appearance of II Zw 174 is due to some hapless companion that strayed too close and is still being "digested" by the galaxy. However a very old paper, 1984 http://cdsads.u-stra...6..961G&db_k... says VLA data indicates there's a hidden companion behind II Zw 174. At that time the idea of galaxies feeding on each other wasn't well accepted. I couldn't find anything newer on it however.

NED classes II Zw 174 as SB(s)bc? pec. The NGC project agrees saying SBbc/P using its system. It is also in the Kiso Ultra violet excess Catalog (KUG 2213+189B). This would support a tremendous amount of star formation going on in the galaxy. UGC 11964 is listed by NED as simply Sd though some other sources say Sc. Considering how featureless it is (at least visually) I can understand the differences.

NED has no redshift data on any other galaxy in my image and only lists 13 others (all from the 2MASS) in the field though I see several hundred anonymous galaxies.

I see faint hints of scattered stars well outside the galaxy, especially to the southeast. I'd planned on taking a lot more data, and in fact did take over twice what I used. Unfortunately, I didn't give up until long after I should have so ended up throwing out a lot. Thus I wasn't able to show but a hint of what I think should be seen to the southeast.

14" LX200R @ f/10, L=5x10' RGB=2x10' (some rather poor), STL-11000XM, Paramount ME

Full frame at 1" per pixel
http://www.spacebant...ntid=4586&stc=1

Attached crop at 0.67" per pixel.

Rick

Attached Files



#2 LazyLightning

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Posted 28 April 2013 - 12:49 AM

Interesting pair, NGC7241 reminds me a bit of M82 minus the filaments of course. Nice shot Rick!

#3 Mike7Mak

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Posted 28 April 2013 - 12:24 PM

Those star clusters must be a spectacular sight for denizens of that galaxy. Nice shot.

#4 Jim Thommes

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Posted 28 April 2013 - 01:59 PM

Rick,
Nice work. You do have a knack for imaging the oddities that the cosmos has to offer. I think this one qualifies as one of your weirder ones.

#5 bill w

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Posted 28 April 2013 - 04:08 PM

interesting galaxy
the blue blobs are something
good luck to the neighbor

#6 zoran

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Posted 29 April 2013 - 03:16 AM

Very nice image of a very strange galaxy!
Regards,
Zoran

#7 Rick J

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Posted 29 April 2013 - 01:45 PM

Thanks all. I do wish seeing had been better. It has a lot more detail than my seeing allowed. Unfortunately much of 2012 and so far this year has had rather poor seeing.

I do like the rarely imaged and strange objects. This one has been posted here by others before so falls more in the strange category.

Summer skies (this was taken last August) have fewer of these strange galaxies so the next few will be more commonly seen objects but I hope seen from a somewhat different point of view thanks to my 3700mm focal length.

Rick

#8 rigel123

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Posted 01 May 2013 - 03:36 AM

Great shot Rick, very interesting pair!

#9 lambermo

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Posted 11 May 2013 - 01:08 PM

Is that a planetary nebula or a ring galaxy to the north of NGC 7241 ?

It's listed as USNOA2 1050-20180368 at wikisky , the object page at http://server3.wikis...t_id=1026813328 does not have much on it, bit it shows in both your image and at the DSS2 survey : http://www.wikisky.o...04858571&zoo...

ps. I first wanted to know what the vague galaxy to the left of NGC 7241 is (USNOA2 1050-20184610) but then saw the ring object in your image :)

-- Hans

#10 KidOrion

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Posted 11 May 2013 - 03:05 PM

Very cool.

#11 Rick J

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Posted 11 May 2013 - 08:58 PM

Is that a planetary nebula or a ring galaxy to the north of NGC 7241 ?

It's listed as USNOA2 1050-20180368 at wikisky , the object page at http://server3.wikis...t_id=1026813328 does not have much on it, bit it shows in both your image and at the DSS2 survey : http://www.wikisky.o...04858571&zoo...

ps. I first wanted to know what the vague galaxy to the left of NGC 7241 is (USNOA2 1050-20184610) but then saw the ring object in your image :)

-- Hans


I was going to mention that apparent Hoag Object like ring galaxy but, like you, came up empty. It is listed in several catalogs NED says is fully included yet NED doesn't list it. I've seen this before and never did get an explanation. Same for the other galaxy you mention.

I assume the ring is a ring galaxy as SIMBAD which is very good about listing all planetary nebula doesn't list anything at its position either.

I should have mentioned that in the original post but somehow missed including it, even though I had it underlined in my notes not to miss.

Rick

#12 Fred76

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Posted 29 August 2013 - 04:32 AM

Hi.

Following a post by JP Beausoleil on the french astronomy forum Webastro, I look at Rick's photo and found a quite strange and faint circular feature :

Posted Image

Would it be a nebula or is it some dust not removed by the flat ? Rick, could you check that on your RAW images ?

Fred

#13 Rick J

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Posted 30 August 2013 - 04:00 PM

The dark spot (tache sombre) is real as it shows on the Sloan image but the ring is most likely due to a moving dust mot due to a screw in my filter wheel coming too lose allowing the filter to align differently each rotation and thus not matching the master taken a couple day's and many rotations earlier.

Rick

#14 Fred76

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Posted 31 August 2013 - 04:24 PM

Well, after a review of the RAW files, Rick confirmed the "circular" pattern was an artifact caused by the conjugation of a dust mot and a undesirable movement of a filter.

However the "dark trace" is something real that needs more detailed imaging. It is only 6-10 arcsec in size and shows in the DSS, SDSS and POSS images.

Big diameter and long focal length is required to capture that feature. It is very faint but does not look like a galaxy.

Fred

#15 Fred76

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Posted 02 September 2013 - 04:03 AM

The coordinates of the dark trace (t√Ęche sombre) are, J2000 :

RA : 22h 16m 02.0s
DEC : +19d 20m 42.7s
>>> SDSS DR9 Image

Posted Image

Should someone elect to shoot this very very faint object, he could also frame this curious neighbour, suspected to be a Hoag type galaxy (very rare), at :

RA : 22h 15m 49.8s
DEC : +19d 20m 7.3s
>>> SDSS DR9 Image
Posted Image
Both objects are in the range of 20 arcsec in diameter so a large telescope together and a good seeing are required to get good resolution.







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