ARP072

In Arp's class "spiral galaxies with small high surface brightness companions on arms"; "faint material from arm to and around companion. Opposite arm faint, sweeps around east of galaxy" (Arp)

NGC 5994 (small galaxy), 156 million light-years distant and classified S? and discovered by William Herschel on March 21, 1784 but isn't in either Herschel 400 program.
NGC 5996 Starburst galaxy SBc pec located 157 million light-years away and discovered by Bindon Stoney on March 9, 1851.
NED note says; "The UV spectrum of this starburst (classified as such by Balzano 1983 on the basis of optical data) is similar to the one of the prototype NGC 7714. Here also Si IV and C IV show P Cygni profiles, a signature of Wolf-Rayet stars. A high far-infrared luminosity confirms the presence of vigorous star formation (Deutsch & Willner 1987). This activity is possibly triggered by the strong interaction with the companion NGC 5994 (Bushouse 1987).

Limiting magnitude of this image is about 24.5! See ID image for details. Most galaxies with redshift data are about over 3 billion light-years away. NED lists over 1700 galaxies within a 23 minute circle centered on my image (not Arp 72 which is a bit high as I wanted to catch the interacting pair at the very bottom. Since all but a very few are brighter than 24.7 and the field is 33 minutes wide, not 23, I probably caught more than 2500 galaxies in this image but you may have to blow up the image to see them all. Not bad for only 40 minutes of luminosity data! Math says 3038 so I'm being conservative. The two galaxies marked with their distance are magnitude 20.2 and 20.6, left to right. This was a night of better than average seeing and transparency.

I moved Arp 72 high to catch the two possibly interacting galaxies at the bottom of the image west of center (right). The big galaxy is SDSS J154629.02+173914.4 at magnitude 17.2. Unfortunately, there is no redshift data on it. The small round "companion" is SDSS J154629.94+173918.9 at magnitude 18.2. Redshift data is available for it and puts it at 1.2 billion light years. Both seem to have about the same intergalactic reddening so probably are about the same distance. But whether the smaller galaxy is just superimposed over the halo of the larger or they are really interacting I don't know. The very blue elongated galaxy to the NW is SDSS J154625.91+174017.7 at magnitude 18 and a redshift distance of 650 million light years. The reddish round galaxy SE of the possibly interacting pair is SDSS J154634.61+173850.2 at magnitude 17.3 and a redshift distance of 1.3 billion light-years, about the same as the nearby pair.

The round galaxy above and a bit west of Arp 72 is SDSS J154649.41+175902.0 at 620 million light years. The somewhat smaller blue "bug splat" of a galaxy above and east of Arp 72 is SDSS J154712.85+175727.2. It is far smaller than the former galaxy being only 160 million light years distant. Thus it is likely related to Arp 72 and judging by the vivid blue color likely interacted with it in the past, triggering massive star formation that is still going on.

East of Arp 72 level with the companion is a "small spiral with a very dense core and faint disk without arms. It is SDSS J154714.35+175153.1 which is 1.7 billion light-years away. Above it at further east is a double galaxy, the eastern one being nearly starlike. The main one is SDSS J154722.89+175309.7 at 1.4 billion light years. I can't find the eastern one in NED! Checking the POSS 2 blue plates the second galaxy is plainly seen. Why the SDSS missed it I don't know.

Due west of Arp 72 is a small slightly oval blue galaxy. It is SDSS J154641.50+175337.2 at 620 million light years. Further west is the more elongated blue galaxy cataloged as SDSS J154633.14+175300.4. It is shown at 630 million light years so likely related to its nearby companion. They are surprisingly blue for their distance.

At the eastern edge, near the center are three rather bright galaxies. The western and northernmost is a double blue galaxy. It is listed in both the SDSS catalog and the MCG catalog. The can't seem to agree on its position nor its redshift. It is SDSS J154757.80+174921.5 with a redshift of 600 million light years or MCG +03-40-041 at 500 million light years. Take your pick! It could be that they are measuring the redshift of different galaxies in the pair. If they aren't really related this difference could be real. Further east and south is the apparently much larger yellowish elliptical galaxy known as CGCG 107-038 or ARK 485. The latter indicates it is an emission line object. Something you don't expect of an elliptical galaxy that should have used up all its gas long ago and thus not have strong emission lines. It may be bright and interesting but I couldn't find a redshift value for it. I was hoping notes at NED would help me but there was only one and it told me only what was obvious from my image; "Elliptical red object with an envelope." Below it is another very blue spiral, SDSS J154802.94+174538.4 at 440 million light years. Above these three, nearly directly north of the mystery double blue galaxy is a reddish galaxy with what appears to be a very disturbed outer envelope. It is SDSS J154756.71+175216.1 at 1.2 billion light years. There are several nearly starlike galaxies around it, could one of them be responsible for so disturbing this galaxy.

There are hundreds of other galaxies I could mention, such as the tiny reddish but bright galaxy SE of the bright blue star below Arp 72. It is SDSS J154704.34+174833.0 at 1.3 billion light years yet shines at 18th magnitude. But I have to stop somewhere or write a book on this field so I'll stop with the comment that oddly, NED lists no quasars in this field. For going so deep I found that surprising.

Arp's image with the 200" telescope is at:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp72.jpeg

14" LX 200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP072

ARP073

Arp 73 is a pair of galaxies in Northern Hercules at about 415 million light-years. It falls under Arp's class "Spiral Galaxies with Companions on Arms: Small, high surface brightness companions." Their general catalog names are IC 1222 and SDSS J163514.15+461232.6 right to left. IC 1222 is classed by NED as SAB(s)c. Arp's comment: "Arm leads toward, but not up to companion." In my image it looks like the arm does pass by the companion and overlaps the tidal arm toward IC 1222. That seems in conflict with Arp's comment unless he was talking only about the core of the companion. I find no classification of the companion. It reminds me of M110 and its tidal arms due to M31 though the arms of M110 are fainter. NGC 1222 was discovered by Lewis Swift on July 10, 1890 as was IC 1221 discussed below.

When taking this image I knew IC 1221 was at the very top but thought I'd left enough room for it. But after seeing the full 10 minute subs the next day I realized it had a faint arm that stuck out from the others that came off the eastern side and went nearly straight north out of frame before curving west. I tried retaking the data the following night but seeing was a good 1" worse so after two frames I quit the effort. Somehow I forgot about it until starting to process it some 8 months later. Thus I missed the interesting part of IC 1221. It is unrelated to Arp 73 being only 250 million light-years away. NED shows it as an Sd spiral. To the northeast of Arp 73 is a small galaxy that appears to be a neighbor as it has a distance of 425 million light-years. Then to the west-northwest of Arp 73 is SDSS J163357.26+461701.6 at 415 million light-years, the same distance as Arp 73. Directly below it is another member of the group, SDSS J163353.82+460932.2 at 412 million light-years.

I've attached an annotated image with the distance to Galaxies and Quasars listed. Just southeast of Arp 73 is a quasar candidate so I used QC to identify it. Seems that it isn't a point source and is elongated from the southeast to the northwest. My software reports it has a FWHM diameter of 2.89" while the stars in the area average about 2.1" with the largest being 2.25". Well under this object. So I am seeing a galaxy here that might contain a weak quasar or AGN of some type at least. Then toward the east-northeast edge of the image is yet another quasar candidate with a FWHM of 2.7" while all the stars around it are about 2.1". This would again indicate something that is not a point source as you'd expect a quasar to be. This one is 3 billion light-years distant.

Also marked on the annotated image is a candidate galaxy cluster listed as NSC J163438+462142 at 1.8 billion light-years. Unfortunately no size or galaxy count is given. I've noted the position of the center of the cluster (just south of NGC 1221) but there's nothing right there. Most galaxies in the area have no red shift data. Of those that do, one south of the location is at 1.7 billion light-years and likely a member. What about those around it? The only other ones with red shift data are far beyond the cluster's distance. I wish I had more information. A far better galaxy cluster with information is found in the lower left corner of the image, ZwCl 1635.0+4613 at 3.1 billion light-years. I've noted what is said to be the center of the cluster. Many galaxy clusters have a one or two large elliptical galaxies that anchor the cluster. Those appear just south of the center. They likely get to be the big gorillas of the cluster by feeding on smaller members. The cluster contains some 196 members in a 15 minute radius of the center. I found no red shift data on individual galaxies in the cluster.

As usual, I have a blue, low surface brightness galaxy that the SDSS has either missed or NED isn't including. It is in the northeastern quadrant and identified by a question mark. Note that right on its north edge is a star-like object. That is at the exact location (to 0.05" of arc by my plate solve) of the position of SDSS J163631.38+461934.7 a 22nd magnitude galaxy. There must be a systematic reason why these galaxies are missed but I don't know what it is. Yet another of these is at the top edge on the left. Again marked by a question mark. The galaxy below the question mark, almost providing the dot is 16h35m55.7s +46d23m02s a 20.5 magnitude galaxy.

SDSS image of Arp 73
http://astronomerica.awardspace.com/SDSS-5/IC1222.php
SDSS image of IC 1221 showing the arm I cut off
http://astronomerica.awardspace.com/SDSS-5/IC1221.php

Arp's image, very different than mine. At first I thought I'd imaged the wrong galaxy until I looked more closely. His is under exposed compared to mine.
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp73.jpeg

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

Related Designations for ARP073

ARP074

Arp 74/UGC 01626 is a pair of galaxies not far from Gamma Andromeda. Arp put it in his class for spirals with high surface brightness companions on their arm. Red-shift puts it about 240 thousands of light-years away. There is no redshift data that I could find for its companion Arp 074B. A note at NED reads: "Companion 0.75, 169, 0.20 x 0.15, interaction. The arms appear to join close to the companion." This dates back to a 1973 paper. I don't see the interaction they mention. The fact the two arms happen to appear to meet near the position of the other galaxy seems immaterial as to decide if they are interacting or not. Arp 074B doesn't appear distorted. If interacting the smaller galaxy should show more distortion than the larger yet shows no sign of any distortion. There's no redshift data on the little galaxy to help me decide if they are related or not. For now, I'm saying they aren't related.

Arp 74 is classed by NED as SAB(rs)c. While the arms are obviously very different they don't earn it a peculiar designation. Unequal arms are rather common in fact. No interaction appears necessary either for the shape nor the high star formation rate these often have. Arp 074 is classed as IrS. Arp's comment on this one reads: "Broad, diffuse extension of arm leads to companion." Rather different from NED's note the arms appearing to join at the companion. Is Arp hinting that the arm leads to the other because they are related? I think he considered it a possibility that needed further investigation. That still hasn't happened it seems. Most likely Arp 74B is a distant background galaxy. The main galaxy appears to have little to no dust in its outer arms to dim a distant galaxy making it impossible to tell if it lies behind or not.

There is little on the rest of the field. There is a spiral at the bottom of my frame that seems as distorted as Arp 74 but didn't make his list. It is UGC 1615. It is classed as SB(s)dm: at NED. There's no distance estimate for it or any other galaxy in the field.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp74.jpeg

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

Related Designations for ARP074

ARP075

Arp 75/NGC 702 is possibly an interacting pair of galaxies in central Cetus about 465 million light-years distant. Arp put it in his category for spirals with high surface brightness companions on the arms. As to what constitutes his companion, I'm not sure. At first, I thought he meant the very blue star cloud in the northern arm. But his comment reads: "Very faint extension to companion." That would rule out the blue object. About all that is left is the galaxy to the left, one and a half minutes left. A small oval galaxy. The rather blue extension is really a huge faint plume that envelops a much larger area than the bright parts of the galaxy. It would seem just happenstance that this other galaxy is within this large faint disk. NED shows the blue star cloud-like object well within the brighter portions of the galactic tangle as having virtually the same redshift as the main galaxy. So it is likely related. No redshift data is available for the one at the eastern edge of the faint star plume, APMUKS(BJ) B014853.58-041809.1. It likely lies far beyond or is a dwarf much closer. All speculation without redshift data. It appears this is an interacting system, just not the one Arp describes. The other galaxy may be the blue object or maybe the double core some sources mention. Maybe it's a triple system. It does seem to have an odd dark lane to the west (right) of the brightest core region and another parallel dust lane on the opposite side of the double core that is somewhat further from the core. The other "major" galaxy near Arp 75 is APMUKS(BJ) B014836.83-041711.8 to the west. Again, no redshift data but I doubt it is related.

A note to the MCG catalog entry a few years prior to Arp's Atlas describes this one rather colorfully as: "Remarkable interaction. The form is similar to the lower part of the body of a bending man, who has a sword between his legs (an elongated galaxy E). To the south is a short spiral arm." A note at NED from a year later says: "Bright complex lens with double nucleus. Faint outer whorls or (R): 1.75 arcmin x 1.55 arcmin. Probably an interacting system." NED and the NGC project classify it as SB(s)bc Pec.

The double core is very obvious in my image though burned in in Arp's image. There appears to be a third orange something above the two cores. Is it just a field star? A star knot? I have no idea. NGC 702 was discovered by William Herschel on September 20, 1784 but isn't in either Herschel 400 program.

There's not much data on the rest of the field. Only three other galaxies have redshift data. They are all above Arp 75. Right to left they are the flying saucer-like edge on with dust lane, MCG -01-05-040 at 233 million light-years; the small disk galaxy to its upper left, LEDA 144362 at 548 million light-years and LEDA 144374 further left, a bit left of center-line and just below an orange-white double star, is 623 million light-years away. Only MCG -01-05-040 has a classification. It is listed as SB(r)0+ Pec? I don't know what feature gives it the peculiar tag.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp75.jpeg

14" LX200R @ f/10, L=4x10 RGB=2x10x3, STL-11000XM, Paramount ME

Related Designations for ARP075

ARP076

Arp 76 is better known as M 90 and IC 3583. Arp put it in his category for spiral galaxies with small, high surface brightness companions. The redshift of M 90 is actually a blue shift indicating it is moving toward us. Still, there's good reason to put the galaxy about the middle of the Virgo Cluster and thus about 60 million light-years distant. IC 3583, the "companion" on the other hand has a redshift that puts it about 67 million light-years distant. It does appear somewhat distorted. While it was considered a possible companion of M 90 at the time of Arp's atlas most today doubt that due to the very different redshifts meaning any interaction would have happened at such high speed neither would have noticed the passage. M90 is classified by NED as SAB(rs)ab;LINER;Sy. The NGC project says simply Sb. Seligman agrees with NED but adds a question mark, SAB(rs)ab?. It was discovered by Charles Messier on March 18, 1781 along with many others. IC 3583 was found by Isaac Roberts on April 29, 1892. Seligman classifies it as SBm? pec. One interesting note at NED discussing if it is a companion of M90 or not reads: "Non interacting pair with dwarf IC 3583 at 6.0 arcmin north. Possibly interacting." Now that's covering your backside!

This image dates back to 2007 when my processing skills and tools were limited as was my imaging technique. I need to redo this one.

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp76.jpeg

14" LX200R @ f/10, L=9x5' RGB=3x5', STL-11000XM, Paramount ME

Related Designations for ARP076

ARP078

I've never been happy with my 2008 image of Arp 78. I tried this August on a night of good seeing to get better luminance data. Unfortunately, the weather didn't cooperate the couple nights seeing was up to what I wanted. I tried anyway but only the core region of the galaxy had enough signal to be usable. I've merged that into the previous image. Thus only the core region shows any improvement. Below is some of the text from the original 2008 post.

Arp 78/NGC 772 is a spiral galaxy in Aries about 100 million light-years away. Arp put it in his category of spirals with small, high surface brightness companions on their arms. He also has a category for galaxies with one heavy arm. Since the companion isn't on a spiral arm, just nearby, I'd have thought the heavy arm category suited it better. Though the companion may be the cause of the "heavy arm". NED classes Arp 78 as SA(s)b with HII emission while the NGC project's simpler classification is simply Sb I. Neither call it peculiar which I find, well, peculiar. To me, it isn't just the long drawn out heavy blue arm but all the debris scattered about it due to a past interaction that would earn it such a designation. At a distance of 100 million light-years, the galaxy would be some 234,000 light-years across including the fainter extensions and plumes to the south-east and north-west. Including just the brighter inner region makes it 150,000 light-years across. Any way you look at it this is a large spiral galaxy.

The companion is NGC 770. It is at the same redshift as Arp 78 indicating they are true companions. All the debris in the area could indicate it is the interacting galaxy that did the damage though it is little distorted which bothers me a bit. Not a lot as it is a highly condensed, high mass galaxy that could withstand such an interaction with a spiral without a lot of obvious damage. NED classes it as E3:. The colon indicates some question over this classification. The NGC project says simply E. Most papers indicate they are likely interacting.

While the Sloan Survey has imaged this field the data hasn't as yet been picked up by NED leaving me little to go on. NED lists a quasar behind the galaxy of magnitude 19.63 but gives only a very general position. Looking at the Sloan image I find a knot in Arp 78 has right at its southeast end a very strong, very blue, round object of the correct brightness. Without NED's ultraviolet capability it appears white in my image. I've noted it but with two ?? as I'm quite unsure of the identification. It is [HB89] 0156+187 for those wishing to follow up on this.

To the west of NGC 770 is a galaxy, 2MASX J01590722+1857368, at a distance of 880 million light-years. NED lists it as a "Poss. dwarf gal." I find this very odd. For that distance, it would be about 115 thousand light-years across. By that measurement, our galaxy is also a possible dwarf galaxy! They don't show any question about the accuracy of the redshift measurement. To compound this issue, LEDA 212884 at 860 million light-years would be even larger at 142,000 light-years. It too is listed by NED as a "Poss. dwarf gal." When I first wrote up Arp 78 NED didn't have any redshift data on these two galaxies. I mentioned without it there was no way to know if they too were companions or not. I didn't note if NED had the "Poss. dwarf gal." note at that time. If so, the note may be a holdover from 2008 when the redshift data was unavailable. Other than that I know of no way to explain this situation. Wish I'd kept better notes back then.

To the east of Arp 78 is a small galaxy at 110 million light-years. It's only identification in NED is [WGB2006] 015624+18430_g. (Since this post it has made other listings such as KIG 0080:[VOV2007] 211 I used in this annotated image not having read this text first.) It is likely part of the same group as Arp 78 and NGC 770. It would be a true dwarf at about 16,000 light-years in diameter. NED has nothing to indicate this however nor does it try to classify it. [WGB2006] is the Woods, Geller, Barton catalog in case you were wondering. (And the VOV is the Verley+Odewahn+Verdes-Montenegro catalog.)

The only other galaxy with redshift data is UGC 1445 at about twice the distance of Arp 78. NED lists it as an S0 galaxy. In fact, it appears to me to be a rather classic example of this type of galaxy. Bright core and featureless, rather red disk of old stars indicating star formation ceased some time ago in the galaxy.

There are 7 asteroids in the image, a couple very faint. When I originally looked up this data I covered only three of them. Until recently the Minor Planet Center only allowed you to go back two years when looking up asteroids. They have greatly improved the speed and accuracy of their computer system. Now they allow you to go back much further though not all asteroids will show up this far back in time. Also, some have no magnitude data or it is obviously very wrong. Two it listed at magnitude 4 and 5! But the positions were very close. In fact more accurate than the old 2 year system was. Sometimes it only returned the asteroid number and not the yearly designation. When this happened by entering that into the ephemeris calculator I was able to get the full name. So they have a bug or two to work out but I do like the improved accuracy and ability to go back further in time to when I wasn't being very good about recording such data. (Since I wrote this those bugs have been fixed. I used the corrected asteroid data for this annotated image.)

Arp 78 was discovered by William Herschel on November 29, 1785 and is on the original Herschel 400 observing list. My notes from September 10, 1985 with my 10" f/5 from only a mile away from my present location so very dark skies but hampered by high humidity (normal for this location) reads: "Large, slightly irregular galaxy with faint difficult star-like nucleus. Appears to be a near face on spiral with some hint of detail in the spiral arms. Even a hint of its spiral nature can be seen. A very interesting galaxy."

Arp 78 is a huge galaxy. Due to all the debris from the interaction, it is hard to decide how to measure it. I get a size of 255,000 light-years though others say 245,000. But if I include the faint far-ranging debris its diameter is 350,000 light-years, In any case, it is over twice, maybe 3 times the size of our galaxy. Over time as the debris falls back into the galaxy it likely will shrink somewhat.

The companion NGC 770 was discovered by R. J. Mitchel on November 3, 1885.

The new data was taken binned 1x1 on a very hazy night with low transparency while the original was taken binned 2x2 also on a rather poor night for transparency according to my notes, just not as bad. I need to try yet again as there's a lot more detail I failed to pick up.

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp78.jpeg

14" LX200R @ f/10, L=4x10'x2+8x10x1 (the new data) RGB=1x10x3 (clouds prevented any new RGB), STL-11000XM, Paramount ME

Related Designations for ARP078

ARP079

This is a reprocess of an image taken back in 2009. My processing toolkit was limited as was my ability to use what tools I had. So it was time to redo it after I looked at it and got an instant yuck reaction in my stomach. I cheated by starting with a partly processed TIFF luminance image and since the color data looked good but for color balance I used it as I had processed it the first time except to adjust color balance some, mainly to remove airglow that tends to be strong at my latitude. Also, I wasn't doing annotated images back then. There was enough else going on I needed to go into that I had skipped in the original post 6 years ago.

This is a two for one Arp image that contains both Arp 79 and Arp 117. Arp 79 is listed by Arp under the category for spiral galaxies with high surface brightness companions. But there's no such companion. Arp's only comment on the object refers to the two star knots in the southern arm saying; "Small separation between two knots in arm." There is an orange field star in the other arm but I don't see how that looks anything like a companion galaxy either. Some have said he is referring to the brightening of the arm where those two star knots are located but since he refers to them and the brightening looks nothing like a companion I can't imagine that was his intent. It does have a strange feature, a straight bar of blue stars that appears separate from the galaxy seen below the two star knots. It's far from being of high surface brightness but could be considered a companion I suppose. I find nothing on it.

The right of two star knots in the arm is SDSS J141007.08+173647.6 which NED does call a galaxy rather than part of a galaxy but I've seen many such star knots listed this way so I don't put a lot of credence into that classification. The other star knot isn't listed at NED at all nor is the bar. Seems there's lots of mystery to this one. While it looks like a small spiral it is actually pretty normal sized at 70,000 light-years. It's just its distance that makes it seem small. It is sometimes known as NGC 5490C (NGC 5490 is at the bottom of my image) and is classified as SB(s)bc.

Arp 117 is listed by Arp under his classification for elliptical-like galaxies close to and perturbing spirals. Thus by his classification, the small galaxy is perturbing the big one. Arp apparently sees this as a warping of the spiral for which he notes: "Flattening of spiral's nucleus appears to be in a different plane than the arms." I'm not so sure I see what he is talking about. The core is very bright with a bright but short bar. Does he see this as a spiral seen edge on inside a face on set of arms? Other than this I don't see what he is talking about. While both galaxies have the same redshift and thus likely about the same distance from us it also could be their relative motions are actually quite different but their distance difference covers this up. I'd think there'd be distortions in the smaller companion as well as the spiral. I don't see that the companion is anything but very normal looking. It is IC 982, a SA0+ galaxy and the spiral is IC 983 an SB(r)bc galaxy. Note that except for the pseudo ring structure its classification is the same as that of Arp 79 even though they appear very different.

Arp 117 (both galaxies) was discovered by Stephane Javelle on May 27, 1891. IC 982 is about 80,000 light-years across while the spiral IC 983 is absolutely huge at over 325,000 light-years dwarfing everything around it.

Note in the annotated image there are many dwarf galaxies with a redshift indicating they are part of the same group. Many having almost exactly the same redshift in fact.

The other major galaxy in the image is NGC 5490 that for some reason I didn't get entirely on the frame. It is listed simply as an Elliptical galaxy and has a very similar redshift to the two Arp systems. Indicating it is likely part of the same group. It was discovered by William Herschel on March 14, 1784. It is in the second Herschel 400 observing program. I can't directly measure its size on my image since it is partly out of the frame. Using NED's diameter it would be about 125,000 light years in size using a distance of 250,000 million light-years determined by mostly type 1A supernova measurements though redshift places it a bit closer and thus smaller. It may be its own group as there are other galaxies around it with redshifts a bit less than that of the two Arp systems.

Arp's image of #79
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp79.jpeg

Arp's image of #117
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp117.jpeg

14" LX200R @ f/10, L=4x10' RGB=2x10' binned 3x3, STL-11000XM, Paramount ME

Related Designations for ARP079

ARP080

Arp 80/NGC 2633 is located in northern Camelopardalis with a redshift distance of about 100 million light-years. Other distance estimates range from 89 million light-years to 108 million light-years with a mean value of 96 million light-years. The latter is in surprisingly good agreement with the redshift value. Arp put it in his category for spiral galaxies with large high surface brightness companions. His comment reads: "End of one arm heavy; absorption break in same arm near nucleus." Note it doesn't mention the "high surface brightness companion." Could that be because it doesn't exist? This has to be one of the most puzzling entries in his atlas. I'd think a high surface brightness companion would be easy to spot but where the blankety-blank is it?

The VV catalog seems to add my confusion when it reads: "3 or more galaxies with one or two "bridges" (at the left). All nearly in contact. Bordered by an arc above and below and still further above by a wide spiral arm. ... The upper arc is terminated by zigzags, or by a chance projection of a remote nest." Until that last sentence, I thought I might have the wrong galaxy but it does show a nice squiggle at the end of the upper arm. That arm is quite a bit brighter than the other arm. The UGC makes the most sense when it says of Arp 80: "Arp's class 'galaxies with one heavy arm' appears more appropriate." Amen to that! I believe the absorption break Arp speaks of is at the other end from the squiggle right where it meets the core region. At least I see a strong dust band cutting straight across the arm there which is a very unusual feature. But I can't fathom the companion or companions Arp and the VV catalog mentions. Best I can do is the "zigzag" or "nest" at the end of the arm that the VV catalog mentions.

It was discovered by Wilhelm Tempel on August 11, 1882 as was NGC 2634 below. NGC 2633 is classified by the NGC Project and NED as SBb. Seligman says SB(s)b pec?

It does, however, have a companion. It is LEDA 213530 about 3 minutes to the south and a bit east. Far from being on an arm, it is apparently a true companion having exactly the same redshift, 2160 km/s. NED classes it as Im. It is quite blue as are a surprising number of the galaxies in this image.

Below it is yet another companion NGC 2634. It is classed by NED as E1: and simply as E by the NGC Project while Seligman says E1?. Usually, elliptical galaxies are composed of old red stars but this one has outer shells of blue. The POSS plates also show it brighter in blue than red light. Continuing south yet we find yet another group member, NGC 2634A. NED and Seligman classify it as SB(s)bc? sp. The sp means it has spectral lines. It is apparently an edge on barred spiral. It certainly has some bright knots of activity in it. The shells of NGC 2634 are usually an indication it is digesting a rather large meal after cannibalizing another galaxy well into the past. I find its shells more interesting than Arp 80. Arp has a class for such shell galaxies but didn't include this one though to me its shells structure is better defined than some he did include. All notes at NED agree it is not interacting with NGC 2634A.

Those 4 are the only ones with any redshift data but there are other interesting galaxies in the image that I marked in the annotated image. MAILYAN 035 is a very low surface brightness, and very fuzzy spiral galaxy that is also very blue. The designation is from the Mailyan Dwarf Galaxy Catalogue. So apparently it is a small galaxy much closer than the previously mentioned galaxies. Though without redshift data this is only a guess.

Every object NED lists in the field has been annotated. Most with a ? for distance. A few that would seem reasonable for NED to know about aren't listed. Probably because those that are are either from the 2MASS catalog of 2 micron objects which omits galaxies without 2 micron radiation which usually means lots of warm dust or they are objects with strong ultraviolet radiation. These are noted by UvES. Often these are quasar candidates though they can be just stars with unusual UV radiation and even galaxies. One that is certainly a galaxy is at the top of the image left of center. The others are star-like but without redshift data, I can't tell if they might be quasar candidates or not.

The entire field is full of IFN, galactic cirrus. Unfortunately, my color data is somewhat noisy due to clouds so it looks rather noisy. This image was taken over a couple nights but still was severely hurt by clouds.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp80.jpeg

14" LX200R @ f/10, L=8x10' R=4x10' G=3x10' B=2x10', STL-11000XM, Paramount ME

Related Designations for ARP080

ARP081

Arp 81 is NGC 6621 and NGC 6622. Arp put it in his category of spirals with large, high surface brightness companions. While many he considered companions are now known just to be line of sight galaxies that are unrelated. That's not the case here. This pair is located in Draco about 280 million light-years distant. The small southern galaxy is NGC 6621. It is classified as Sa by NED, Sbc by the NGC project and (R)SBa? pec by Seligman. It is thought to be orbiting NGC 6622 and has dawn out the large plume running around NGC 6622. It was discovered by Lewis Swift on June 2, 1885.

Note that more than a couple sources claim NGC 6622 is the southern rather than northern galaxy. Dreyer noted however it was the northern one. Why this puts them out of Right Ascension order I don't know but this isn't the only pair with this issue.

NGC 6622 is the large galaxy with the huge plume drawn out by NGC 6621. It is classed as Sb: pec HII;LIRG by NED, Sb/P by the NGC Project and Sb? pec by Seligman. It was discovered by Edward Swift the same night as his father is said to have found NGC 6621. Did dad let son have credit for this one? Edward was only 14 at the time. Edward is credited with finding 25 NGC objects and 23 IC objects. All were when he was 13 to 20 years of age. Why nothing after that?

The Hubble Space Telescope has studied this pair. Rather than retype it here's the link: http://www.astr.ua.edu/gifimages/ngc6621.html . For those wanting a deeper discussion see: http://arxiv.org/PS_cache/astro-ph/pdf/0309/0309674v1.pdf .

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp81.jpeg

14" LX200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP081

ARP082

Arp 82 consists of two NGC galaxies. NGC 2535 is the big galaxy, NGC 2536 the small companion. NED and Seligman classify 2535 as SA(r)c pec while the NGC Project simplifies it to Sc pec. NED and Seligman classify 2536 as SB(rs)c pec while the NGC Project says simply Sbc pec. Both are about 200 million light-years distant. The (r) indicates a ring structure. Note the arms come off the ring in both cases not and not the cores of the galaxies. Both were discovered by Édouard Stephan on January 22, 1877. Arp put them in his category for spirals with large, high surface brightness companions. In this case, it appears that he got it right.

Both galaxies were discovered by Édouard Stephan on January 22, 1877.

See the annotated image for information on other galaxies and quasars (Q) in the image. If NED shows only a position for a name of a galaxy I've used G rather than the long position name to keep label clutter to a minimum.

Three asteroids are identified in the annotated image. Since I took color data after the first four luminance frames then went back for four more luminance frames their trails have a break in the middle.

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp82.jpeg

14" LX200R @ f/10, L=8x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP082