ARP220

Arp 220/IC 4553 is the closest known Ultra Luminous Infra Red Galaxy (ULIRG) known and one of the brightest. Though all this was unknown at the time of Arp's atlas. This was discovered initially by the IRAS satellite. A press conference to announce these objects that the scientists didn't realize were galaxies at the time has been used by, first the believers of the 2003 Zeta/planet X end of the world and then by the 12/21/2012 end of the world believers of "planet Nibiru" to "prove" this mythical planet exists. If it wasn't this galaxy that caused the furor it was one like it. I was a supervisor of a public observatory back when the Zeta fiasco happened and was reviled by some for not showing them this non-existent planet. I don't miss those days.

Arp puts this one in his class "galaxies with adjacent loops". While this one is one of the most studied of all Arp galaxies he had no comment on it. It is located in Serpens Caput about 250 million light-years away. NED classes it as S?. It has LINER and Seyfert 2 characteristics.

At one time it was thought that visually we were seeing two galaxies not quite yet in contact. Then it was realized the "gap" was a dust lane and we see only one galaxy. Radio telescopes and then IR telescopes showed it had two cores hidden behind the dust that are only 0.9" of arc apart. It really is two after all. Since it shows somewhat contrary signs of being an AGN and being a starburst galaxy some think this is due to one galaxy harboring a very active AGN and the other having strong starburst activity. One paper suggests that the two massive black holes will merge in a billion years or less. Appears I'll miss that event if it happens. Another galaxy at the same distance as Arp 220 is on the eastern edge of my image.

The annotated image shows a large number of galaxies all with the same redshift that puts them at 1.2 billion light-years. I found no reference to a cluster, however. One galaxy is at 1.3 billion light-years. Due to rounding to 2 significant figures there is nearly a 120 million light-year difference in their distances so it isn't likely related.

I had great difficulty imaging this one. I started in April of 2010 and tried many nights through until the last subs were taken on June 18. Out of all that I got only 2 good luminance frames and two badly hurt by clouds which bloated the brightest stars, especially the one to the northwest of Arp 220. But the high clouds settled seeing so those were the sharpest. In order to get enough signal for a decent image I used the 11 RGB images (one blue was lost to clouds) and stacked them with the 4 luminance frames I used to make a pseudo luminance image. This worked better than I expected, resulting in a far better image than I expected to be able to put together. Just ignore the bloated brighter stars the clouds gave me. Also due to most images being heavily filtered by clouds and RGB filters this one doesn't go as deep as normal. It barely reaches magnitude 21 instead of the 22.5 I commonly reach. I've been trying again this year but so far the clouds have said no way. I decided to try processing what I had and am happy with the results so likely won't put it on the reshoot list.

It was discovered on July 25, 1903 by Stephane Javelle.

Since this one is so highly studied I have other images to refer.

A radio image showing the two cores can be found in figure 12 and 13 of this paper
http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1996ApJ...465..191M&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf

Kitt Peak image with the 2.1-meter telescope in near IR and H alpha (my image suddenly doesn't appear so bad)
http://www.astr.ua.edu/gifimages/arp220.html

Chandra X-ray image of the cores
http://chandra.harvard.edu/photo/2002/1181/

HST NICMOS image in near IR showing the two cores
http://hubblesite.org/image/484/news_release/1997-17

HST visible light image (suddenly my image is really putrid)
http://www.spacetelescope.org/static/archives/images/large/heic0810bf.jpg

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp220.jpeg

14" LX200R @ f/10, L=15x10' RG=4x10' B=3x10', STL-11000XM, Paramount ME

Related Designations for ARP220

ARP221

ARP 221 is a triple galaxy in Hydra about 3.5 degrees southeast of Alphard, Hydra's lone 2nd magnitude star. Arp classified it as a galaxy with amorphous spiral arms making the comment: "Faint diffuse material to south, bright filament to hard image on NW side of nucleus." Sounds awkward but is the way he wrote it. Apparently, he was ignoring the two close companions though NED and others consider all three part of Arp 221. All three have the same redshift putting them 260 million light-years from us. It appears rather obvious the main galaxy has been highly disturbed causing the tidal plumes Arp called amorphous arms. NED classifies it as I0 Pec. It may have been a spiral. Is it interacting with one or both of its close companions or is it the result of a merger. I found nothing on it to help decide this question. The south end of the halo has a sharp, well-defined edge looking like a shell. These are usually a sign of a merger so I'm leaning in that direction. Also one or both of the "arms" (especially the on the NW side) may be the remains of its dinner showing the path it followed while being ripped apart. Another reason I favor the merger option.

Several other galaxies much further distant from ARP 221 show virtually the same redshift distance indicating this is a group of galaxies but I found no cluster or galaxy group cataloged for this position. Unfortunately, this part of the sky is poorly studied. What few galaxies had redshift data are shown in the annotated image. The largest dimension of its halo measures some 2 minutes across in my data. That makes the galaxy, including plumes, about 150,000 light-years across.

I had thought I'd taken all Arp galaxies north of 15 degrees south, my normal limit unless the night is extraordinarily good. But over a year ago a sweep of the hard drive showed me I had missed two. Well, I'd tried them several times but seeing and clouds were too much. Apparently, I thought I had good enough data and removed them from my to-do list. Then when I found they weren't worth processing never put them back on the list. I fixed that last year but weather and bad seeing continued resulting in more failures. This year I've been trying again with similar results. Finally one night I just had time to catch this one under good seeing for its -11 degree declination. But it entered my Meridian Tree ruining the second green frame. The first had a horribly bright satellite across the top of the frame. Cloning and the Hasta La Vista Green filter made for a successful repair.

I've included in the annotated image a few that had no redshift data. Those that only had coordinates for their "name" were found in either the 2MASS IR survey or the Galex Ultraviolet survey so carry the designation of IrS or UvS. One was in both so has both marking it. Many weren't in NED at all. One that appears part of a pair of contrasting colors fell into that hole and is noted by a question mark even though it was much brighter than many that were in NED. Without redshift nor names other than their position I didn't annotate the vast majority in the image.

The minor planet center showed an asteroid in the frame I should have picked up but didn't. That puzzled me until a few weeks later when I checked again and now it was listed as lost. So the coordinates I had were wrong.

Arp's image of this one with the 200" Palomar scope can be found at:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp221.jpeg
For once he put north at the top same as I have it.

14" LX200R @ f/10, L=4x10' RB=2x10' G=1x10', STL-11000XM, Paramount ME

Related Designations for ARP221

ARP222

Arp 222 is NGC 7727, a very disturbed spiral classed as SAB(s)a pec by NED, S(B)a pec by the NGC project and a mess by me. Arp included it under galaxies with amorphous spiral arms. It is very similar to Arp 223 as well as near it in western Aquarius. But is only about half as far away at 70 million light years. Like Arp 223 it has a nearby companion at about the same distance, NGC 7724 to its west. It is classed as (R')SB(r)b pec? by NED and Sb by the NGC project. The arms do make a near ring but nowhere as nice as that of Arp 223's companion. I'm stumped as to why NED considers it possible peculiar other than the near ring like arm structure. Since that is fairly common I don't see that as peculiar. NED shows it to be 73 million light years distant but that's well within the error bar of redshift distance measurement so which is really closer to us is pretty much a coin toss.

Notes at NED indicate it is likely the result of a merger as two nuclei are seen. Looking at my image at 3x I see a red object due east of the main core and a white object to the north-northwest. The later may be a star as it appears a bit sharper. One note says it is 3" from the main one but doesn't give a direction. That would be the north-northeast object. The note says it could be just a star as their resolution of 0.7" (better than mine at 1") wasn't sufficient to tell. If they can't I certainly can't. Still, it does have the appearance of a merger so I'll go with that for now. The galaxy seems to have a nearly vertical axis and a nearly horizontal one. That and its style of distortion matches known mergers such as Arp 192 leads me to this conclusion. Arp is of no help having made no comment on either 222 or 223.

Since this area is so little studied I never thought to check out Hubble until I was just about to post this. When I did I found an image of the core that clearly shows this is a merger in progress and that northern object is the second core, a much smaller one than the main one, likely because it has been stripped of most of its stars by the merger. So the merger idea appears correct. I've included this Hubble image. It also shows my red patch is just a loop of stars torn out by the merger process. I've also included a highly processed version of my image that may show the second core. Or it is just enhanced noise.

While NGC 7724 is nearby it shows no distortion so I doubt it is interacting with Arp 222. This is also the conclusion of the NGC project and several notes at NED. Still, it is an interesting galaxy in an otherwise rather drab image. The colors of both are rather weak with both being rather white in color, not a lot of star formation going on in either it would seem.

NGC 7727 was discovered by William Herschel on November 27, 1785. It is in the original Herschel 400 observing program. My comments with my 10" f/5 on September 6, 1985 at 60x bothered by some aurora reads: "Small, tight, elongated patch of galactic light. Rapidly brighter toward the center."

There's little information on what few galaxies there are in the image. The only other galaxy of note is the small two armed (very faint arms) barred spiral in the lower left corner, 2MASX J23405811-1223374 at about 900 million light years.

There are two asteroids in the image. The one at the top directly above Arp 222 is (152825) 1999 UE49 at magnitude 19.1. It is moving virtually directly west. In the lower part of the image well east (left) of center is (106135) 2000 TE42 at magnitude 18.7. It is moving at a steeply inclined angle to the southwest.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp222.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP222

ARP223

Arp 223 is entered in his catalog under amorphous spiral arms. It is also known as NGC 7585 and is in the constellation of Aquarius just below the Circlet of Pisces. Redshift puts it at about 145 million light-years away. Most sources say it is the result of a merger of two galaxies but do admit they find no hint of the second galaxy saying it must have been some time ago and it is now fully absorbed. They note the presence of NGC 7576 10.7 minutes to the southwest (also in my image) but dismiss it has being too far away. But again admitting that it too is about 145 million light-years distant with virtually the same redshift as Arp 223. It is a ring galaxy which often is the result of an encounter. Neither shows any tidal streamer that you'd expect from an encounter so probably the experts are right, still, I have to wonder a bit. But see its near-twin Arp 222.

I screwed up taking this one. I've had NGC 7592, a triple interacting Arp "wanna-be" galaxy on my to-do list for several years. It is just 15 minutes north of Arp 223. Somehow in my muddled middle of the night brain (cloud alarm woke me at 1 a.m. to say the sky has cleared get imaging), I thought I needed to put it high in the field to pick up NGC 7592 but it should have been low! ARGH. I could have captured all three if my brain had been working on even half its neurons. As of this writing, I'm yet to capture NGC 7592.

Edit: Since then NGC 7592 has been imaged and includes Arp 223.

NGC 7585 was discovered by William Herschel on September 20, 1784 but isn't in either of the Herschel 400 observing programs. Neither is NGC 7576 which he found on October 5, 1785.

I did catch 4 asteroids in the image. In the upper left corner partly out of frame is (8943) Stefanozavka at magnitude 18.4, slightly to its west is 2005 SK58 at magnitude 19.3. Down near the lower left corner is 2000 AY204 at magnitude 17.6. Toward the lower right corner, under NGC 7576 is (14021) 1994 PL20 at magnitude 18.3. Magnitudes are estimates by the minor planet center and can be off quite a bit it seems. You may wonder why the second asteroid has no number. Asteroids get a number only after their orbit is fully determined. This usually takes at least one full orbit. That hasn't yet happened for 2005 SK58. There is a bright streak through a star near the top of the frame, left of center. The streak was caused by a tiny speck of dirt on a filter that happened to exactly hit the star's position.

Several catalogs list an 18.7 magnitude quasar just southwest of Arp 223 a bit over about 1.4 minutes away and just on the edge of the galaxy as seen in my image. Since I easily picked up a 19th magnitude moving asteroid an 18.7 magnitude quasar should be very obvious. I don't see it, nor do I see it in Arp's image of the galaxy. Either it is much fainter than listed or the position is wrong. It's [VCV2001] J231758.8-043954 and yes the coordinates in its name match the position where I don't see it, just about 10" NE of a tight unequal double star. But the position has an error bar of 100 seconds of arc so it could be anything within 100" of that position. While I checked every star none measured 18.7. Closest is one of 19.3 directly south of the galaxy core. Why it's position is so uncertain I don't know.

This field is too close to the Milky Way's dust (Zone of Avoidance) so not covered by the SDSS. This means there's little information on this entire field. Only one other object has a redshift given (besides the lost quasar). It is a small galaxy nearly 10 minutes west and slightly north of Arp 223. It is just beside a dim star to its upper right. It is listed at 2.1 billion light years. So while there is a paucity of galaxies compared to my normal posts that isn't Because I'm not going as deep, they just aren't there.

Arp's image is at:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp223.jpeg

14" LX200R @ f/10, L=4x10' RGB=1x20'x3, STL-11000XM, Paramount ME

Related Designations for ARP223

ARP224

ARP 224, NGC 3921, is considered to be a merger in progress. Simulations indicate it is about 0.5 to 0.8 billion years since the merger began. It is part of a cluster of galaxies about 275 million light-years distant and is in the bowl of the Big Dipper not far from Phecda (Gamma Ursae Majoris). Arp included it under Galaxies (not classifiable as S or E): amorphous spiral arms. Though a note in NED incorrectly says it is under the preceding category, adjacent loops. Arp's comment: "Straight filament leads to bright offset nucleus." Yet his image shows it to be slightly curved. The CGCG catalog notes: "Blue disk-like post-eruptive compact with large external loop and extended jets." I would imagine given another billion years or so those stars will settle back into the galaxy creating a large elliptical galaxy. For now, it appears one galaxy left the huge looping tail while the other left the shorter and weaker slightly curved tail. I see only one well-defined core. Since the smaller tail appears to connect to it I'll go out on a limb and say it is the source of that tail. Could it be, it being more massive, pretty well tore up the other less massive one creating the huge looping plume ending in what appears to be a bunch of small "cores" arcing north of the main core? Is that all that's left of its core or is that hidden behind the other one? I'm only guessing here.

Directly west of Arp 224 is SDSS J115059.24+550413.5 looking like a dwarf spiral and below it is SDSS J115059.33+550310.0 an even smaller dwarf elliptical. Both are at about the same distance as Arp 224. Also, a member of the group is NGC 3916, the SAb spiral to the northwest of Arp 224 as is the smaller spiral to the SW that appears to harbor a "Saturn" like core in my shot. It is MCG +09-19-213.

The galaxy cluster ZwCl 1148.6+5523 is just about centered on Arp 224. It is said to have about 121 members and is about 50' across, far larger than my image.

The galaxies in this image seem to fall into several distance categories. The Arp 224 group being the closest. Then there's a group at about 775 through 820 million light years. A typical member is the round galaxy southwest of MCG +09-19-213.

Another group is at 1 billion light years and seems to be likely the group referred to in the Zwicky cluster. It is centered on the giant red elliptical galaxy a short distance northeast of Arp 224. The Zwicky cluster's center is about half way between it and Arp 224. Most of the obviously orange galaxies around this area appear part of this group.

Then there's a scattering of even more distant galaxies, such as SDSS J115036.68+550915.0, the star-like very orange galaxy west-northwest of NGC 3916. It appears brighter than its rated 18.8 magnitude and far more distant than you expect at 2.7 billion light-years.

The annotated image shows the distance to non-Arp 224 group galaxies when known. All galaxies showing detail but without a distance shown are members of the Arp 224 group at about 275 million light-years.

Arp's image:
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp224.jpeg
SDSS image:
http://astronomerica.awardspace.com/SDSS-29/NGC3921.php
Hubble Space Telescope -- core
http://hubblesite.org/image/533/news_release/1997-34
Hubble Space Telescope -- southern half of Arp 224
http://hubblesite.org/image/526/news_release/1997-34

Sorry, I couldn't find any larger versions of the Hubble images, the data in the archive wasn't complete enough from what I saw to make a larger version.

14" LX200R @ f/10, L=4x10 RGB=2x10, STL-11000XM, Paramount ME

Related Designations for ARP224

ARP225

Arp 225/NGC 2655 is a nearby strange galaxy in Camelopardalis. Redshift puts it about 65 million light-years away though a Tully estimate says more like 80. I'm going to go with the closer figure as even that distance makes it a huge galaxy some 170,000 light-years across. The more distant estimate makes it about 210,000 light-years across. I doubt it is that big. The galaxy was discovered by William Herschel on September 26, 1802. It is in the original Herschel 400 observing program. My notes made on the night of April 14, 1985 at 100x under fair conditions using my 10" f/5 reads: "Small, faint, circular puff of a galaxy with a small but not starlike nucleus."

It is obviously a highly disturbed galaxy. Arp put it in his class for galaxies with amorphous spiral arms. He said of it: "Very faint diffuse outer arms, absorption one side of nucleus." NED classes it as SAB(s)0/a while the NGC Project says S0/Sa. Several papers call it a Seyfert 2 galaxy. I found only one paper addressing the "amorphous" arms. It refers to LEDA 3085822 which is the large rather evenly faint blob to the northwest (about 2 O'clock) near the upper right corner of the enlarged, cropped image. The paper refers to it as An 0849+78. http://adsabs.harvard.edu/cgi-bin/bib_query?1996A%26AS..117..343K It says: "An 0849+78 is located at the extension of an outer spiral arm of NGC 2655 and seems to be connected to it by a very faint bridge. Its isophotes are of regular shape; a faint elongated nucleus is marginally visible. The light profile is probably non-exponential, but its outer part is poorly determined due to the uncertainties in background subtraction. The HI observations show that An 0849+78 is confused by NGC 2655, at V_h_ = 1400 km/s. To calculate the absolute characteristics we use for An 0849+78 the distance of NGC 2655. If An 0849+78 is a bound (dwarf spheroidal) companion of NCC (sic) 2655, its survival in the gravitational field of the bright galaxy is problematic. New multicolour photometry and HI observations are needed."

So it appears the "arms" could be really the tidal tail of a dwarf galaxy being pulled apart by NGC 2655 as it orbits the much larger galaxy. NED gives the "blob" almost the same redshift as Arp 225 which supports this idea. The dust near the core likely is from this now almost annihilated galaxy. While I found no paper willing to go this far it seems the most reasonable explanation of what is going on here. Besides the above paper, another would go this far: "NGC 2655 = Arp 225 is an Sa galaxy which shows traces of a strong interaction or merger event: faint outer stellar loops, extended HI-envelope (Huchtmeier & Richter 1982). The bulge in NGC 2655 is especially large (Table 4). The central dust-structure (Erwin et al. 1996) is probably the reason for the disturbed fit residuum there."
http://adsabs.harvard.edu/cgi-bin/bib_query?2001A%26A...368...16M

Yet another paper coming close to saying these loops are due to galaxies being destroyed is:
http://iopscience.iop.org/1538-3881/135/1/99 but put on your hip waders if you haven't already.

There is an odd, likely background galaxy seen right through the outer parts of Arp 225 almost directly north of the core. It might be two galaxies superimposed or even a star and galaxy. This is almost certainly a background object(s). In any case, the two look somewhat like a comet. The only thing NED shows at almost that position (about 1" different from its centroid) is the infrared source 2MASXi J0855445+781451. It doesn't indicate this is a galaxy but it just might be this object. In fact, NED has very little on this field which is common for these galaxies up near the celestial pole. It has a redshift for only one other galaxy, UGC 04701, the nice Sd: near edge on spiral east of Arp 225. It has about the same redshift as the other two so they are likely part of a group. Two-thirds of a degree east of Arp 225 and well out of my image is a very nice spiral NGC 2715 also with a similar redshift. It is a nice spiral showing little sign of being disturbed. It went on my to-do list once I could reach this far north but weather last year prevented any of its photons being captured. (It has been taken since this was written).

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp225.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for ARP225

ARP226

Arp 226/NGC 7252 is often known as the "Atoms for Peace" galaxy. It is considered to be a galaxy merger. It is about 200 to 220 million light-years away (depending on who you read -- 200 by redshift) and is located in the constellation of Aquarius, right along its southern border at -24 degrees. This puts it way too low for me to image. Over the lake atmospheric extinction is almost 2 magnitudes this low and I get severe chromatic smearing. Blue is weak that low as well making obtaining color data difficult. My color balance is very questionable this low as conditions change greatly between the time I take G2V calibration star and the image is complete. Doesn't help such stars aren't at that elevation. Higher up this is easy to but this low the standard formulas don't apply due to the humidity from the lake. I usually avoid going this low but as this is a famous galaxy, I had to give it a try. Many tries, that is. I started in July and finished in October with over 100 frames taken. The vast majority were too distorted, fuzzy, faint or otherwise unusable. This was a nightmare to piece together and far lower resolution than I'd like but considering how low it was it's about as good as I can hope to do. I had to use all the tricks in my bag to turn the streaks in the L frame to sort of round stars. Pure RGB would be better but didn't begin to have the frames for it.

The galaxy is thought to be the product of a collision of two spiral galaxies that are forming a giant elliptical galaxy. It appears that globular star clusters may be being created by the collision explaining why many such elliptical galaxies have so many globular clusters.

The galaxy is classed as (r)SA(r)0 at NED and SB0 at the NGC project. It was discovered by William Herschel on October 26, 1785 but is in neither of the Herschel 400 observing programs.

For a good ground based image of it see:
http://cseligman.com/text/atlas/ngc7252.jpg

I can't see much resemblance to the "Atoms for Peace" stamp it got its name from but you can try here:
http://en.wikipedia.org/wiki/Atoms_for_Peace

It is a famous merger featured in the classic paper by Toomre on determining the sequence with time in galaxy mergers. You can read more on that here:
http://astronomy.swin.edu.au/cms/astro/cosmos/t/Toomre+Sequence

The Hubble Space Telescope shows that its core is a rather normal looking spiral galaxy with no hint of the other galaxy. Was it completely torn apart leaving the looping star trail and plumes?
http://www.spacetelescope.org/static/archives/images/large/opo9311a.jpg

At the bottom of my image, a bit right of center,+ is the galaxy 2dFGRS S063Z192 at 800 million light-years. It appears as 2 galaxies in my image. NED's position is the dark gap between them. Each appears nearly circular but NED shows the galaxy as 2.8 times longer than high. This fits the size and shape of both round blobs. I still think it is two galaxies but my resolution is too poor to say for sure.

Toward the end of the northwest plume is a blue object. NED calls it NGC 7252W and gives it the designation of "galaxy". Is it really one or a star cloud in the plume? The HST image doesn't include it. It does have a similar redshift to Arp 226. To the northeast is the obvious separate barred galaxy NED calls NGC 7252 COM01. It too has a similar redshift as does 2dFGRS S063Z143, a small dwarf galaxy to the east of Arp 226.

Due to the severe extinction, I get this low over the lake the image loses about 2 magnitudes over my normal images. Chromatic dispersion elongates the stars as well. It needs many hours of exposure but this low I get only an hour a night and that only when seeing is very good. This makes it impossible for me to get the time needed. After 5 months this is all I could get.

There are three asteroids in the image. Since the 4 images used for the L image were all taken different nights, only one of which contained the asteroid, I had to "adjust" the image to show them. I used the 4 frames taken the night these three were in the image only for the asteroids. I had to adjust for varying focus as well. Other asteroids were in the other three frames used for the luminance image but they only appeared in one frame so a complete 40 minute track didn't exist, they were arbitrarily cloned out of existence. Nearest Arp 226 was (259764) 2004 BY4 at magnitude 19.3. Next closest to the southwest was (248913) 2006 VQ80 at magnitude 18.5. At the very top near the middle was (39603) 1993 TU20. It is listed as also magnitude 18.5 but obviously was far fainter. The images used for these 3 asteroids was taken on August 12, 2010 centered on about 6:10 UT. None of the frames were used for Arp 226 or anything else. I should have just ignored them but I like including the trails.

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp226.jpeg

14" LX200R @ f/10, L=4x10' RGB=3x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP226

ARP227

This is another retry at an Arp entry I wasn't happy with the first time around. I wanted to get a lot more time but the weather had other ideas and most of the data wasn't usable due to horrid seeing and clouds. There's a lot to talk about here. It's a long read for those interested. The rest can just jump to the pictures.

Arp 227 falls into Arp's category for galaxies with concentric rings, modern astronomers refer to it as a shell galaxy. It is located in Pisces about 93 million light-years distant by redshift. Many papers say 100 million which, given the uncertainty of redshift distances is a nice round estimate I won't argue with. It consists of two galaxies, NGC 474, the shell galaxy and a true companion NGC 470 to the west. Some sources deny NGC 470 is part of Apr 227. Arp did frame his image to give 470 and 474 equal weight but didn't list it as a member. Another shell galaxy is in my image, NGC 467 to the southwest but it would seem to be unrelated being some 2.5 times further away. While not exceedingly rare, shell galaxies with such well-defined shells as these two are uncommon, to have two in the same small area of sky exceedingly rare. I don't know of another example.

NGC 474 is classed as (R')SA(s)0^0^ at NED and (R')SA(s)0 at the NGC project. Shell galaxies are thought to form a couple different ways. One is a direct radial hit by a small, low mass, galaxy that is destroyed in the process. Stars are flung out, turn around and fall back. This, in simulations, causes them to linger for a bit as they turn around creating an area of higher density. Those with further orbits before the companion was torn apart go out further to a more distant turnaround point. Thus high star density shells are formed. I don't pretend to begin to understand this concept. The other method involves a grazing impact that also destroys the companion. In this case, its stars are flung out into spiral-like loops that then loosely wrap about the host galaxy like a fishing line snarl open face fishing reels can create. At least I can understand the fishing line snarl but the rest still eludes me. See: https://apod.nasa.gov/apod/ap140105.html for more on this and a much deeper image than mine. Arp, always the contrarian, has a really weird explanation. The companion spirals in creating the rings. We do see some such rings, in fact, there's a few around our galaxy due to dwarf galaxies our galaxy has and still is in one case, dining on. But they are far from sharply defined as they are in shell galaxies. Arp though goes on to say that both 474 and 470 are the remains of a larger active galaxy and that the two quasars near 470, see my annotated version, were ejected from the center of the original disrupted system. Of course, he uses his reworked physics to explain away their redshift that puts them billions of light-years behind these two galaxies.

So how does NGC 470 fit into this? Wish I knew. It is classed as SA(rs)b by both NED and the NGC project. Its arms are unusually thick and uneven. That could be perfectly natural for it. Or could this be due to interaction with NGC 474? NGC 470 does have some small possible plumes coming off either end that might indicate interaction with NGC 474 but I doubt its gravity is sufficient to create the shells in the much larger galaxy yet be so little influenced itself. Most papers on 474 say there's no other evidence of a collision with another galaxy but for its shell structure. No second nucleus or apparently evidence for two planes of stellar motion. Though if the idea the companion was so low density to be totally destroyed the lack of anything else but the shell structure isn't all that surprising to me, but I'm far from an expert on this! I found papers saying the two are and are not interacting. I vote with the latter (barely) but will reserve the right to change my vote if better evidence for interaction is found.

NGC 470 and 474 were discovered by William Herschel on December 13, 1784 while NGC 467 was found by him on October 8, 1785. None of these are in either of the Herschel 400 observing programs.

A third member of the group is MGC +00-04-083 to the southwest. It has about the same redshift but doesn't appear to be interacting with anything and is quite small and insignificant compared to the other two. A distant galaxy appears to overlap it to the NW of its core. This little guy, as with most in the image is anonymous.

Then there's the other shell galaxy NGC 467 at nearly a quarter billion light-years. It too has a companion, to the east-southeast this time PGC 1249151. I can't find a redshift for it. Is it a true companion or just a line of sight galaxy? Like NGC 474, besides the well-defined shells, it too has plumes. The most obvious to the south but if you look closely there's a faint arc of stars even further north than the bright plume extends south. I needed more time to bring these out in both galaxies. CGCG 385-068 at the very bottom of my image to its southeast has a similar redshift and shows a faint tidal tail. While I can't see it as causing the shells it could have had some interaction creating the plumes I suppose.

This is one very busy image that could have used a lot more time. Maybe a third try is needed.

There are 5 asteroids in the image, one seen atop the shells of NGC 474. Details are on the annotated image.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp227.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for ARP227

ARP228

Arp 228/IC 0162 is the largest and likely anchoring galaxy of a small cluster of galaxies. USGC U076 is one designation NED uses. Their redshift distances range from 220 to 250 million light-years. The difference is mostly due to their orbital velocities about a common center of gravity. Since Arp 228 is likely the anchor its redshift of 223 million light-years may be a good estimate of the distance to the group. It is classed as S0. Arp put it in his class of concentric ring galaxies. It appears his image failed to pick up the extent of the outer ring. At least the outer ring I picked up. Deeper shots may show yet another ring for all I know. Arp 228 likely is the end result of a normal spiral fattened up on many smaller galaxies in its group.

MCG +02-05-039 just to its southeast is a very odd looking galaxy. NED doesn't try to classify it. Is it being distorted by Arp 228? Sort of reminded me of a Vargas Girl, big bust, tiny waist and large hips. Its redshift puts it at 230 million light-years which may be yet another indication it is getting whip-sawed by Arp 228. To the west of Arp 228 is another pair of galaxies. IC 0161/UGC 01266 and UGC 01266 Notes01. They show redshift distances of 230 and 250 million light-years respectively. The little guy may also be getting whip-sawed by the gravity of the larger or they may just be along the same line of sight. A note at NED says IC 161 is nonexistent but most say it does. It is true Swift's position for it and 162 were poor with 161 being right at his magnitude limit but most credit him with both galaxies The Kanipe-Webb book only uses the MCG designation but NED itself gives IC 0161 as its primary designation for the galaxy. The IC description of 161 may not fit. It says "considerably extremely faint, very small, round." Though the visual observers may only be seeing the core which is round. For comparison the description of 162 which is Arp 228 reads, extremely faint, small, little extended. That would indicate only its core was likely seen as well. Most say Lewis Swift saw IC 161 on January 8, 1891 and IC 162 on October 3, 1889. What causes some to say 161 is nonexistent or lost is that it is fainter yet was found first. Being so close together they question him seeing the fainter one but missing the brighter. But galaxy visibility depends on surface brightness. Due to IC 161 having a starlike core and a large but low surface brightness disk it could be Swift mistook it for a star. Not having tried to see either visually I can't say if this is possible or not.

UGC 01268 north of Arp 228 is classed as S? It appears to be a red spiral of some sort. Its redshift says it is 220 million light years distant, the closest of the group but again this may not necessarily be the case.

UGC 01263 is the face on spiral to the northwest of Arp 228. It too is classed as only S? It appears to be a barred spiral with a ring and outer arms. It certainly is peculiar. Redshift puts it at 227 million light years. It seems unusually red for such a spiral. The pair of red double stars between it and Arp 228 are much redder than I normally see. Are they a true pair I wonder?

The only other galaxy in the image with a redshift is MRC 0145+102. It is listed at 21.4 magnitude but no filter is given. My normal limiting magnitude is about 22 and from the estimated brightness of the asteroids in the image it would appear I'm reaching at least magnitude 22 probably 22.5 or so. But this one is far fainter than that would indicate. It is a radio source. I've noted the optical component on the annotated image, southwest of Arp 228. According to NED, it has a redshift of z=2.845000! That means the light I'm imaging was well into the ultraviolet when it left the galaxy some 11.4 billion years ago. That has to be one super object to show a physical size at that distance! You may have to enlarge the image to find it.

I managed to pick up 6 asteroids, most exceedingly faint. I found the three faintest only because the Minor Planet Center said they were there and gave the position. All are shown in the annotated image.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp228.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP228

ARP229

This is my second try at the NGC 507 group. The first attempt was centered on NGC 507 as part of my project to image the Arp Galaxies. But that missed much of the group to the north. Also, the color data with the original was rather poor. This time I got good color data but seeing wasn't so hot. Since the framing is very different I couldn't use the good color data with the better seeing of the first image. The group is located in the northeast corner of Pisces, near M33. Its distance is listed at about 250 million light-years by NED though this seems at odds with the distances of its members. In fact, NGC 507 which appears to be the Big Cluster Galaxy of the group but is shown at only 210 million light-years. In fact, the redshifts of the galaxies NED considers to be group members seems rather centered about this value with only one in my image greater than 250 and most in the 200 million light-year range. Normally I'd not include the distance values in an annotated image but because of this discrepancy did so in this case. A question mark for distance means the galaxy had no redshift value but appears it may be part of the group. A couple oddball blue galaxies weren't in NED at all as galaxies. They are listed only with a question mark. While the data release 8 of the SDSS covers this field that hasn't yet been added to NED so many galaxies are omitted. These two, however, appear highly distorted and may be small members of the group that didn't fare well in interactions. One, northwest of Arp 229 is a very blue irregular mess with several bright star clouds. The other to the northeast of Arp 229 is drawn out into a streak similar to an edge on galaxy but has a dim area a bit southeast of center that shouldn't be in a true edge on galaxy. Is it two galaxies? (Edit: NED now includes these. The NE streak is GALEX J102409.16+332342.7 and the NW mess is GALEX J012320.62+332049.5. Both are identified as a UltraViolet Excess Source but have no distance information.) In the Sloan image which includes near UV light, the lower section is a lot bluer than the upper. That is just the opposite of my image. This would indicate the lower part is full of super hot blue stars emitting mostly in UV light I can't see as my filters block UV light. My corrector plate can't handle that color which would fuzz up my images so I use a filter that limits my coverage to the visible part of the spectrum.

Arp put #229 in his category for galaxies with concentric rings. Arp's comment on NGC 507 reads: "Circular or near circular rings of small density difference". My first try didn't seem to show these rings very well. Even though my seeing was worse for this image the rings show up better.

Besides picking up a lot more of the of the group I also wanted to go deeper so waited for a night of better transparency. I noticed many of the galaxies in the original had a slight hint of extended halos about them. On this better night, I was able to pull those out of the background. Indeed a surprising number of them have halos and plumes. It appears that a large number of these galaxies have had close encounters with other group members in the past. I've pushed the background to higher than normal levels and reduced the contrast a bit between the background and bright objects to better show these faint structures. I would have used more time but the skies were not cooperative.

NGC 507 is a strong radio galaxy and has an extensive X-ray emission out to about 16 arc minutes which is about the width of my image frame! The shells are likely the result of it being well fed on lesser members of the group. The X-rays due to the hot gasses ejected due to its cannibalism. It is classed SA(r)0^0^ at NED and SA(R)0°at the NGC project.

The NGC 507/WBL 038 group consists of 22 members according to NED but no size is given. It is part of the much larger ZwCl 0107.5+3212 which NED lists as containing 625 members in a diameter of 6 degrees at a distance of 220 million light-years. It is centered nearly 3 degrees to the west-southwest putting this group on its eastern edge.

NGC 508 is the other galaxy in Arp 229. It is listed as E0: by NED and E by the NGC Project. NGC 507 and 508 were discovered by William Herschel on September 12, 1784. Neither made a Herschel 400 observing program.

Other major members of the cluster include:
NGC 483 has a very large outer ring that appears totally disconnected from the rest of the galaxy. I find no mention of this ring in the literature. NED classes it as S? and the NGC Project says S. Their visual description misses the ring as well though it is likely too faint to ever see visually. Seligman says (R)S0? so is the only one to take the ring into account. It was discovered by John Herschel on November 11, 1827

IC 1680 in the lower right corner is listed by NED as S0 with no comments. It was found by Stephane Javelle on November 29, 1899

IC 1682 to the left of 1680 is not classified by NED though a note reads: "Elliptical red object." and NED calls it a "high surface brightness galaxy" The latter I see. But it doesn't appear unusually red for an elliptical galaxy though it looks more like S0 to my eye. Javelle found it the same night as IC 1680.

To the north again is LEDA 169765 and 2MFGC 1037. While a close pair optically they show no sign of interaction. So one is likely quite a bit closer. With no data on the IR strong flat galaxy, there's no way to tell which is closer or even if the flat galaxy is a true member of the group. I feel it is but it could be a small galaxy much closer or a huge one further away. Both galaxies are strong in IR light.

NGC 494 lies on the bottom edge. It is listed as Sab by both NED and the NGC project. At first glance, it appears quite normal but look closer and there's a plume on its western (right) side. In the annotated version the label covers up some of it. It was found by John Herschel on November 22, 1827.

NGC 495 to the north is classed by NED as (R')SB(s)0/a pec: and more simply as SB0/SBa by the NGC project. That latter description would be correct but for the huge faint plumes off both of its spiral arms. That apparently is what earned it the pec label. Except for those, it looks like a typical late barred spiral. Interaction with another cluster member likely explains the plumes. William Herschel found it on September 12, 1784.

NGC 496 is a Sbc spiral. It seems to have a normal two-arm structure in the center that expands suddenly to a many arm spiral. Other than that it is pretty normal looking. It was also discovered by William Herschel on September 12, 1784.

NGC 498 is listed as S0 by NED and E by the NGC Project. I see a hint of spiral structure so will side with the S0 designation. It was found by R.J. Mitchell on October 23, 1856.

NGC 499 is also IC 1686. It is listed as S0- by both the NGC Project and NED. It too seems pretty normal for a large galaxy of its type. Another William Herschel found that night of September 12, 1784. But it also got the designation IC 1686 when Javelle found it December 1, 1899 but gave a slightly different position than Herschel not realizing it was the same galaxy Herschel had found a century earlier.

IC 1684 and IC 1685 have no classification at NED. IC 1684 appears to be a rather normal disk galaxy sitting in a larger faint halo. NGC 1685 seems to have two cores, a brighter one well below center and a fainter one just above center. Above that is a star. I can't prove there are two cores, but the PSF of them in my image doesn't fit a star. One may be a background galaxy I suppose. Both were discovered by Stephane Javelle on March 30, 1899.

NGC 501 is a compact E0 per NED and just a compact galaxy per the NGC project. It was discovered by one of the Lord Rosse's assistants, R. J. Mitchell on October 28, 1856.

IC 1687 is also a compact E0 galaxy per NED though it does seem to have a bit of a halo that a compact shouldn't have. Javelle found it on December 1, 1899.

IC 1691 isn't classified at NED others say S? To my eye, it is SB0 or maybe SBa. It looks rather normal. Javelle found it on December 2, 1899.

NGC 503 is Listed by NED as E0? and E by the NGC project. It has a faint large outer halo both seem to ignore nor is anything listed on it in the literature. Such halos are rarely seen in elliptical galaxies as far as I've seen. I'm surprised nothing is being said about it. Makes me wonder if it's the remains of a galaxy that lost a lot of its stars in a past interaction though it seems normal otherwise. It was first seen by Heinrich d'Arrest on August 13, 1863.

NGC 504 is an S0 galaxy. It was discovered by William Herschel's son was discovered by his son John Herschel on November 22, 1827.

ARK 039 is the last strongly haloed galaxy in the image. In this case, it is mentioned in a note at NED which reads: "Elliptical red object with envelope." That's it! I don't see it as unusually red. It looks like a rather typical ring type barred spiral though NED classes it as S? Looks to be it should be SB at least. Though the outer halo (envelope) is very slightly red it is far bluer than the rest of the galaxy which is rather odd. ARK is the Arakelian Emission Line Objects catalog so this galaxy has rather strong H-alpha emission which would fit with it making a lot of stars but isn't a strong IR galaxy so those new stars aren't hidden behind a dense dust shield. This might explain the bluer color to the envelope area. Pure guess on my part.

One asteroid wandered into the scene, 2003 UE 21 at an estimated magnitude 19.6 according to the Minor Planet Center.

Arp's image of Arp 229 is at:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp229.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount ME

Related Designations for ARP229