ARP064

Arp 64 consists of three of the four galaxies that make up UGC 9503. They are located in Bootes about 434 million light-years away. Arp put them under his classification of spirals with small high surface brightness companion on the arms. In this case one companion for each arm. Or as Arp put it "Both arms lead toward companions." At least that's how it looked to Arp.

Redshift data indicates the primary galaxy, PGC 052698, is about 430 million light-years away. But there is no redshift data for either companion. (EDIT: Since this was written the companion above the eastern end of PGC 052698 (LEDA 214322) has virtually the same redshift so is likely a true companion.) The western companion is SDSS J144522.63+192758.3. The one to the northeast is LEDA 214322. As mentioned neither have a redshift measurement that I could find. Without this measurement, it is hard to prove either are true companions. The latter isn't actually on an arm. The arm does make a short jog in its direction but ends abruptly. Maybe a longer exposure would show a connection not seen in my image. In Arp's image, this small galaxy does seem a bit distorted on the side toward the arm. I don't see this however in either the SDSS or my images. The other companion is seen virtually on the end of the other arm. Again it doesn't prove anything but is suggestive.

This accounts for three of the 4 galaxies NED refers to as constituting UGC 9503. Arp doesn't include the fourth in his image. It is the very blue disk galaxy to the south-southeast of Arp 64. It shows a small but faint plume to its south and the disk is rather distorted. Unfortunately, it too has never had a redshift measurement taken. How many of these 4 are truly related I have no idea. Apparently, little research has been done on this group.

To the southwest is the large elliptical like golden galaxy (near the right edge of my enlarged and cropped image), ARK 458. This is a catalog of emission line galaxies. It does have a redshift distance that puts it at 439 million light-years. It is a member of the same group as Arp 64. Being an emission line galaxy it is quite active. It is also an IR galaxy. These two pieces of information are suggestive that it may have had an encounter in the past to trigger such activity. Though this isn't necessary. So could it be the cause of Arp 64's drawn-out arms rather than the two companions? It shows no hint of any distortion, however. Sorry, I have lots of questions but no answers.This accounts for three of the 4 galaxies NED refers to as constituting UGC 9503. Arp doesn't include the fourth in his image. It is the very blue disk galaxy to the south-southeast of Arp 64. It shows a small but faint plume to its south and the disk is rather distorted. Unfortunately, it too has never had a redshift measurement taken. How many of these 4 are truly related I have no idea. Apparently, little research has been done on this group.

Toward the lower right corner is an obvious galaxy cluster with two major galaxy. The one on the right, SDSS J144433.71+192121.5 has a spectroscopic redshift measurement putting it at 2.3 billion light years away. The one on the right, SDSS J144431.76+192127.4 marks the center of the cluster, MaxBCG J221.13237+19.35762. The galaxy has no redshift data but the cluster has a photographic redshift distance of 2.5 billion light years. Since a photographic redshift isn't as accurate as a spectroscopic redshift I assume the 2.3 billion light years of the other major member is likely more correct. It is listed as having 26 members but no size is given. This appears to also be the galaxy cluster Abell 1960 though this has a different center as shown on the annotated image. Abell 1960 is described as having a diameter of 16 arm minutes and a distance of 2.3 billion light years, same as one of the galaxies above.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp64.jpeg

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

Related Designations for ARP064

ARP065

Arp 65/NGC 90 is located in the southwest corner of Andromeda. It is a member of a rather large group of galaxies. I find various names for it but none include all of the galaxies. The group about 240 million light-years from us give or take a few million. I've noted the distances in the annotated image.

Arp 65 is rather near the center of the group. It is in Arp's atlas under the category: Spiral galaxies with small, high surface brightness companions. Arp's comment on this one reads: "Position of open spiral. Comps. lie off projected ends of both spiral arms." That would indicate he is talking about galaxies beyond the extended arms. I see one to the southeast that seems in line with the southern arm. I see two for the other arm but they lie below the arm though there's a slight bend in the arm that might lead to the first and dimmer of the two. I found nothing in the literature on this subject. Note that both spiral arms are double.

The galaxy is classified as SAB(s)c pec by NED, SAB(s) by the NGC project and SAB(s)b? pec by Seligman. It is listed as being discovered by William Parsons by the NGC project in 1854, but Seligman credits his assistant R. J. Mitchell as finding it on October 26, 1854. I measure its size, thanks to its long drawn out arms as 200,000 light-years. So while its diameter is almost that of NGC 80 its mass is far less.

Some sources consider it as interacting with NGC 93 to the east. NED and the NGC Project classifies it as S? while Seligman says Sab? pec. The NGC project also credits it to William Parsons (Earl of Rosse) while Seligman again says R. J. Mitchell on the same night as he found Arp 65.

South of these is a star that is listed as NGC 91. Again there's confusion over who found it. NGC Project credits Lord Rosse in one place and Herman Schultz in another. Schultz was director of Uppsala observatory. I find no connection with Lord Rosse. But Seligman credits it to R. J. Mitchel on the same night as the other two. Since it is a mistake in the first place I suppose all this doesn't much matter.

There are 9 other NGC objects in this image. So here we go.

NGC 79 in the upper right corner is classified as E by NED, as E-So by the NGC project, and E0? by Seligman. All agree it was discovered by Guillaume Bigourdan on November 14. 1884.

NGC 80 is by far the most massive galaxy in the image. I measure it as a bit over 210,000 light-years across. NED and the NGC Project classifies it as SA0-: while Seligman says E/S0?. It was discovered by John Herschel on August 17, 1828.

NGC 81 is a tiny galaxy that NED doesn't even try to classify, the NGC project says simply S while Seligman says S0?. The latter seems about right to my eye. It was discovered by Ralph Copeland on November 15, 1873. He was one of Lord Rosse's assistants but I can't confirm he found this one while working for the Lord though he did find most of his NGC objects there.

NGC 83 is another rather large elliptical. NED classifies it as E but Seligman says (R)S0?. It was discovered by John Herschel the same night as NGC 80.

NGC 85/NGC 85A is listed by NED and the NGC Project as S0 but Seligman again disagrees saying SB0/a? It was discovered by Ralph Copeland the same night as he found NGC 81.

NGC 85B/IC 1546. I'm sort of cheating here as the IC number is most likely its main number. Many catalogs don't recognize it under the NGC number though NED does so I'm going with it. It is classified as S? by NED (The NGC Project doesn't recognize it as an NGC object) while Seligman recognizes it only under the IC number and classifies it as Sbc?. It was discovered by Stephane Javelle on November 20, 1897.

NGC 86 is classified by NED as Sbc, S? by the NGC Project and S0/a? by Seligman. Flip your three-sided coin on this one. It was discovered by Guillaume Bigourdan the same night as he found NGC 79, November 14, 1884.

NGC 94 is listed as S0 by NED and the NGC Project but as S0(s)a? by Seligman. It was discovered by Guillaume Bigourdan the same night as the others in this group but for NGC 96.

NGC 96 is not classified by NED, the NGC Project says S0 while Seligman says SB0? It too was discovered by Guillaume Bigourdan but on October 24, 1884.

Whew, that's 12 NGC objects in a 0.2 square degree field and I'm not near the Virgo Cluster either. Details on other galaxies are in the annotated image when NED had redshift data.

This image dates back to September 2008 when my image processing software and skills were limited. I need to reprocess this one but for now, this will have to do.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp65.jpeg

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

Related Designations for ARP065

ARP066

Arp66/UGC 10396 falls under Arp's category: "Spiral galaxies with small high surface brightness companions on arms." I assume the "companion" Arp is speaking of is the bright object about 21 seconds north of the core of UGC 10396. Problem is that object doesn't appear in NED. Thousands of Sloan survey galaxies are listed in my field. None of which match the position of the bright object. One note at NED says: "Blue condensation 0.12 x 0.10 at 0.35 north center, probably at tip of spiral arm." But it appears completely separate of any arm in my image as well as the Sloan image. Some connection appears possible in Arp's image, however. But to an inner arm, not the one apparently referred to above. Adding to the problems of deciphering this field is the lack of redshift data for anything in the image other than Arp 66's core galaxy. That has a redshift of z=0.020631 which puts it about 280 million light years distant. It is located southern Draco just above its border with Hercules. This one would also fit in Arp's 3 arm spiral category. Seems to have three better-defined arms, one is just a disconnected arc, than some he included in that category.

One note at NED has this interesting comment: "The system's components rotate in opposite directions. The dynamical and photometric centers of both components somewhat differ in position and radial velocity." If true this would indicate the possibility that this is a merger. Could the mystery object be the remaining core of the merging galaxy? If it was I'd think there'd be a strong difference in the centers of rotation seen which doesn't appear to be the case. Could be most of the parts were stripped long ago and now the core is left to orbit the surviving galaxy. That would give the time needed to give more concentricity to the two. But then the comment goes on to say: "The only determination of the central radial velocity found in the literature appears to come from Arkhipova and Esipov (1979). It is listed, e.g., in the UZC catalog (Falco et al. 2000) and is equal to 6185+/-150 km s^-1^. The causes of such a strong discrepancy between this value and our determination (~2500 km s^-1^) are unclear." NED uses the 6185 figure but with a smaller error bar. Apparently, it considers this group's redshift too unreliable to mention. This then makes me wonder about the first part above. For now, I'm "Lost in Space" over this one.

With no redshift data I didn't prepare an annotated image. North northeast of Arp 66 is the very flat, warped disk galaxy SDSS J162704.39+513650.2. I found nothing on it. Why is it's disk so warped? (Warped disks didn't seem to interest Arp.) Could it be related to Arp 66? Seems unlikely but how else to explain the warp? I haven't explored beyond the bounds of my image so the reason may be "out there." To the northwest of Arp 66 is the very low surface brightness disk galaxy, SDSS J162639.02+513533.8. Again no information on it is available to help decide if it could be related to Arp 66 or not. To the southeast of Arp 66 is what appears to be a trio of interacting galaxies. The western one is SDSS J162715.11+513007.1, the northern one SDSS J162715.79+513009.2 and the southern one ... well it isn't in NED. It might be a arm of the western galaxy ripped off by the interaction with the northern galaxy. Without any redshift data anything I can come up with is a pure guess.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp66.jpeg

Unlike most of my images this one was taken and is displayed at 0.5" per pixel rather than my "usual" 1" per pixel.

14"LX200R @ f/10, L=8x10'x1 RGB=2x10'x2, STL-11000XM, Paramount ME

Related Designations for ARP066

ARP067

Arp 8/NGC 497, in the lower left corner in my image, is a spiral Arp put in his "split arm" category. It is a bit over 350 million light-years distant. His comment reads: "Bifurcated arm does not start at end of bar." That would indicate he is talking about the southeastern arm that sticks out. It is a long spur of a rather normal arm. A note at NED reads: "Peculiar broken arm on north-preceding side." This seems to refer to the odd star clouds arranged in a rather straight line on the other side of the galaxy. The middle one is listed in some catalogs as a separate galaxy (see annotated image). NED, however, says it is part of NGC 497. One source even lists it as a quasar candidate which I find really strange. The galaxy was discovered by Édouard Stephan on November 6, 1882.

Arp 67
Arp 67/UGC 892 is located along the top right edge of the image. It is in his category for Spirals with high surface brightness companions on their arms. As I've mentioned before the majority of the galaxies he considered spirals made the atlas for companions of some sort on their arms. In most cases, it was unknown if the two were related. Apparently, that didn't matter. The result is that some turned out to be related, some unrelated and some are still unknown like Arp 88 posted mid-September. In this case, there are two possible companions. Which was the companion Arp refers to? Apparently, both as his comment reads: "Comps. lie on inner and outer spiral arms." Redshift puts Arp 67 at about 225 million light-years. The inner arm spiral has a redshift that puts it about 3 times further at 720 million light years. The one he refers to be on the outer arm has no redshift data but appears to be an unrelated background galaxy as well. Arp 67 is odd in that the "inner arm" seems to be a very odd spur. The main arms form an oval ring. At the northeastern end of the bar an odd linear arm goes across the ring then curves around toward the distant reddish companion. The other lies more on the outer edge of the galaxy's disk rather than an arm. This arm, as well as the faint arms or plumes going out of my image at the top, may be the result of a merger with a small galaxy. This seems more reasonable than two apparently unrelated galaxies being the cause. The inner arm galaxy is SDSS J012117.42-003311.7. For some reason, the outer arm galaxy never made it into any catalog at NED but the United Kingdom automatic plate survey. How everyone else missed it I can't fathom. It is listed in that catalog as APMUKS(BJ) B011845.66-004851.5. In both cases, the name is just the J2000 position.

There are several galaxy clusters in the image. One at about 710 million light-years that covers a major portion of my image. Another is mostly in the northwestern quadrant at 1.2 million light-years. Another is centered on an orange galaxy in the southeastern corner at a bit over 2 million light years. The anchor elliptical galaxy is located at the same position as the cluster though the two have two different listed redshifts.

More interesting are the large number of quasars and Ultraviolet Excess Sources which are likely quasars as well. Some are listed both ways, often in the Sloan survey listing. Several are over 10 billion light-years distance. One is listed as a quasar and galaxy and is only 2.5 billion light-years away. Some pure galaxies are more distant. The most distant galaxy is nearly 5 billion light-years distant. It is above center near the right edge.

4 bright asteroids are also in the image and noted on the annotated image. All are bright enough to have left colored trails as often seen in my image. So why aren't any seen? Seems this image is the product of three nights. The luminance was taken the first night. Clouds moved in ending imaging. Over two later nights, I collected the color data, fighting clouds all the way. But by then the asteroids had moved on. New asteroids had moved into the field and sometimes did leave color trails but without a luminance trail I played God and edited them out. After 3 nights I still only had 2 red frames with the third unusable. But then the moon was in the way. I never did get a third red but one each of the green and blue was poor. With the ending signal to noise ratio about the same in all three colors, I quit trying for a third red.

Arp's image of Arp 8
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp8.jpeg

Arp's image of Arp 67
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp67.jpeg

14" LX200R @ f/10, L=4x10' R=2x10'x3 GB=3x10x3, STL-11000XM, Paramount ME

Related Designations for ARP067

ARP068

Arp 68/NGC 7757 is a Sc spiral galaxy in Pisces at about 120 million light-years. Arp included it in his category Spiral Galaxies with small high surface brightness companions on arms. I'd have put it in his heavy arm category as the "companion" appears to be in the distant background. Arp said the companion was NGC 7756. Lord Rosse who discovered NGC 7756 said this about NGC 7756 "Another neb about 5' sp (NGC 7757)." By "sp" he means south preceding which is south-west. The only object 5' south-west of NGC 7757 is a 12.8 magnitude rather white star. His description is a match for NGC 7757. No one doubts this is a double sighting of NGC 7757. The problem is some sources, like Arp, claim the companion is NGC 7756. This obviously isn't the case. The Kanipe-Webb book gets it right as does NED and the NGC Project. But what is the designation of the companion? It doesn't seem to have one, at least in NED! NED does list an HII region within a couple seconds of arc of its position, however. I can't see it against the distant galaxy. In fact, most of the fuzzy objects in my image don't have any catalog entry that NED shows. Within 15' radius of Arp 68, NED lists only 6 other galaxies, only one of which has a redshift listed. You'll find this galaxy due east (left) of Arp 68 just above a rather bright star. It is the X-ray galaxy GALEX 2690243303817875752 also at 120 million light-years. The very blue galaxy just below Arp 68 and a tad to the east of its center is [HDL96] 407-017. I have nothing much on it.

While Lawrence Parson's did see NGC 7757 it was discovered by John Herschel 43 years earlier on September 24, 1830.

Most sources consider the companion just a coincidence of line of sight that isn't related to Arp 68 in any way. It shows no sign of interaction though NGC 7757 does seem somewhat disturbed. Arp noted the arm saying "Many star-like knots lined up along straight arm." If it has interacted with anything recently the only candidate appears to be the other one at 120 million light years. Being an X-ray galaxy it has apparently been fired up. But there's no real evidence the two ever interacted. A better candidate might be be NGC 7750 about 39 minutes southwest of Arp 68 so well out of my image. It also is about 120 million light years distant and is classed as (R')SB(rs)c pec:. They are too far apart for one frame but I wish I'd realized it was there last fall. I'll try for it this fall weather willing.

The image has quite a few asteroids in it. What's really annoying to me is that THREE (now two) of them are unknown to the Minor Planet Center. Unfortunately, I took this back last September and just recently found the asteroids so there's no way to follow up. They are still lost awaiting discovery it seems. I've "found" about 8 now that I've seen months too late to follow up on. This is getting to be routine with me it seems. I've included an annotated image that shows that identifies the asteroids.

(91197) 1998 SD115 magnitude 18.3
2002 PY124 magnitude 19.2
2005 SZ152 magnitude 19.7
2015 AY94 magnitude 20.2 New since this image was first prepared
2 are still unknown

This field is out of the Sloan survey area so there's very little data available and no professional images, other than Arp's, that I could find on the net.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp68.jpeg
His image appears to have a plate defect at the southwest end of the companion (right in his photo). It appears to be a round stain of some sort.

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

Related Designations for ARP068

ARP069

Arp 69/NGC 5579 is located in Bootes. By redshift, it is about 173 million light-years distant. By Tully-Fisher it is only 130 million light-years away. Flip a coin? Arp put it in his category of spirals with small high surface brightness companions on an arm. There is a companion but it isn't exactly on an arm. It is LEDA 214249 and has a redshift distance of 170 million light years so shares about the same redshift as Arp 69 thus likely is a true companion. Arp has another category this could go in, 3 armed spirals. It might also fit his one heavy arm category for the long south going arm that is rather J shaped. NED and Seligman classes it as SABcd. NGC project Sc. I prefer NED's classification.

Did the companion have anything to do with the distortion of Arp 69? On one hand, it is very low mass and doesn't look disturbed. On the other, it is very blue indicating strong star formation is going on. Still, I doubt it had anything to do with Arp 69's present condition. The Kanipe-Webb book indicates it resembles many very early galaxies seen in the Hubble Ultra Deep Field image. An early galaxy seen in today's universe. In the early universe, galaxies were gobbling up their smaller siblings at a high rate leading to rather distorted galaxies. The universe was much smaller then so galaxies were rather tightly packed making this rather common. It may just be Arp 69 is still digesting some small galaxies, similar to the companion. Certainly, star formation is going on in it at a very high rate which a recent meal could easily cause. If you want an external candidate better than the companion look to the northeast. PGC 051285 is a very distorted, sliver of a galaxy beyond the orange star, at virtually the same redshift as Arp 69. Arp 69 was discovered by William Herschel on May 1, 1785. It is not in either of the Herschel 400 observing programs.

Northeast of Arp 69 is a galaxy cluster anchored by a large galaxy. Both are 2.3 million light-years distant. The cluster is MaxBCG J215.23106+35.23001 with 24 members. No size is given but it appears rather condensed around the position of the core galaxy from my image.

Just southeast of Arp 69 is a somewhat elongated, but nearly starlike object I've listed as both a galaxy and a candidate BLAGN (BLAGN stands for Broad L Active Galactic Nucleus, often indicating a quasar). Some catalogs list it as a galaxy, NED lists it both. Since it is elongated and not a point source it appears some hint of the galaxy harboring the black hole is seen. It is quite close, as quasars go at only 2.5 billion light-years. At magnitude 19.5 it is quite faint for a quasar as well. Must be nearly out of fuel.

A couple NGC galaxies are in the image and several more are just outside its borders. This area would be great for someone with a near one degree FOV with quite a few major galaxies besides Arp 69 in the frame. The other two NGC galaxies each have two different NGC entries. NGC 5588 was first seen by William Herschel on May 1, 1785 and given the NGC 5589 entry. Later on May 9, 1826 his son John recorded it as a different galaxy causing the NGC 5588 entry. Later on April 24, 1827 he recorded it again but at the right position. Apparently not realizing it was the same as the one he say 11 months earlier. A similar father son mix-up happened with 5580/90. William saw it first on May 1, 1785 resulting int the NGC 5590 entry. John saw it on May 9, 1826 and recorded it as the same galaxy his dad saw earlier (note this is the same night he didn't do this with the other galaxy. But then on April 27, 1827 he recorded it at a slightly wrong location not realizing it was the same galaxy and thus it got the NGC 5580 entry. Neither of these two are in a Herschel 400 observing program.

While many galaxies in the field had distance data and are listed in the annotated image some rather bright ones did not. In fact, most of these didn't even have a catalog entry that was more than its position. The lone exception is shown near the bottom left of center with its PGC number and no distance.

I'm often asked how deep do these images go. The faintest object with a magnitude given is a quasar northeast of NGC 5580/90 with a magnitude listed by Sloan as being 23.1 in their green filter. It's also the most distant object with a redshift of over 4 which puts it at over 12 billion light-years distant. This image was taken on April 20, 2010. Then lost on my hard drive until 2016. Back then I had much dryer skies with great transparency. Today I've usually got hazy skies which make it hard to reach even magnitude 22 much to my dismay. The haze seems to have come with warmer weather than we had for decades prior to about 5 years ago. Global warming? If so things will only be getting worse. Doesn't help that seeing has gone down as well which means stars are larger and thus fainter also limiting how faint I can go for point sources. This doesn't bother faint objects that aren't point sources as to how faint I can go but does mean fine detail in them is lost.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp69.jpeg

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

Related Designations for ARP069

ARP070

Arp 70, a pair of interacting galaxies, is in northeastern Pisces about 2 degrees due west of M33. It is about 460 million light-years from earth. Arp put it in his category of spirals with small, high surface brightness companions on arms. There does seem to be a very faint stream of stars coming from the southern, cut-off arm over to the companion galaxy. Though in Arp's image it is difficult to see. It's easier to see a connection from the northern arm down to the companion in Arp's image. There does appear to be a broad band of stars running from the main spiral to the companion coming from the entire western side of the galaxy and going beyond the companion a little ways, if a few thousand light-years can be considered a "little ways".

The main galaxy is UGC 934. It has other designations such as PGC 5085. NED classes it as S? The companion is LEDA 212740 among other designations. NED makes no attempt to classify it. While it appears to be related to UGC 934 NED has no redshift or other distance data so this is possibly an illusion though most see it as a true interacting companion.

NED has no redshift data on any galaxies in the field except UGC 934. Only a dozen or so other galaxies are even identified, all from the 2MASS survey of IR galaxies. The Sloan SR8 Survey has been released but not included as yet. The Sloan image of Arp 70 from this data release comes the closest to my colors of any I've seen so far. Stars are different however. Arp 70 must not have much IR or UV emission for this to happen.

There is one asteroid in the image. It is (255475) 2005 YN165 at an estimated magnitude of 19.7. To find it look near the top of the image directly above Arp 70 to the right of the brightest blue star in the frame and a fainter one. The trail goes up at a rather steep angle and yes the asteroid was moving upward in retrograde motion when this was taken.

The stars in Arp's image are rather elongated. I've seen this when he was capturing two Arp's on one film plate and was pushing the limits of the Winn Corrector that corrects for coma and flattens the field. But there's no other Arp's in the area. The nearest is over 2 degrees to the north, far beyond the field of the 200". Maybe there was something else that interested him but didn't make the catalog. BTW, his exposure was 30 minutes on 103a-D emulsion for this one. 103a-D is most sensitive to yellow-green light. I used 40 minutes for the luminance data with a telescope that gathers only 0.5% the photons. Yes, CCD's are more sensitive than film--a lot more sensitive.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp70.jpeg

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

Related Designations for ARP070

ARP071

Arp 71 is one of four Arp atlas entries in the Hercules Galaxy Cluster (Abell 2151). Most galaxy clusters are made up of elliptical or elliptical-like galaxies. This one is made up of a lot of spiral galaxies which is very rare. Arp 71 belongs to his category for spiral galaxies with small, high surface brightness companions. It is located near the center of the cluster where elliptical galaxies are normally found. The main galaxy is NGC 6045 which NED and the NGC Project classifies as SB(s)c while Seligman adds a question mark. The companion, LEDA 84720, an S07 galaxy is obviously part of the cluster but may not be a true companion, but just a line of sight galaxy in the crowded cluster. NGC 6045 was discovered by Lewis Swift on June 27, 1886. I measure it at about 150,000 light-years, a very large spiral.

This data was taken September 13, 2007. I didn't have the tools to do it justice back then. I need to reshoot this one. It also contains Arp 122, Arp 172 and Arp 272. Details are in the annotated image. The annotated image shows details on many other galaxies in the cluster and beyond it.

Arp's image: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp71.jpeg

14" LX200R @ f/10, L=6x10' RGB=3x10', STL-11000XM, Paramount ME

Related Designations for ARP071

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