ARP322

There are two Arp systems in this image, Arp 214 and Arp 322. They are unrelated. Arp 214 is also NGC 3718. It was discovered by William Herschel on April 12, 1789 though not in either of the Herschel 400 programs which I find rather strange. Arp put it in his category for galaxies with irregularities, absorption and resolution. I don't know what he means by resolution but it certainly is irregular and has a strange absorption dust lane. These features are caused by its long-ago interaction with NGC 3729 to the east. Arp's comment on it reads: "Barred spiral, sharp nucleus, narrow absorption lanes through center." He never mentions the huge plumes drawn out by its interaction with NGC 3729 which itself is rather disturbed but didn't make Arp's atlas. It was also discovered by William Herschel on April 12, 1789 but did make the original Herschel 400 observing program. My comment on it from April 16, 1985 on a fair but humid night with my 10" f/5 at 50x reads "Small galaxy, gradually brighter toward center though no defined nucleus was seen. Smaller and fainter than NGC 3718 in the same field which is easier and more interesting."

The galaxies are a bit over 50 million light-years distant and found in Ursa Major. Both galaxies are experiencing strong star formation as a result of their interaction.

Arp 322 is the other entry to Arp's Atlas in this image. It is 4 of the 5 galaxies seen below Arp 214. It is much more distant at a bit less than 400 million light-years. The 5 galaxies constitute the Hickson Compact Group #56. The eastern member is not considered part of Arp 322. Arp put it in his section for galaxy chains. Other than mentioning that the chain is near Arp 214 he made no other comment on this entry. Did he leave out the eastern galaxy because its halo didn't overlap any other or because it didn't fit his idea of a "chain"? Without any comment on this, your guess is as good as mine.

Arp's image of #214:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp214.jpeg

Arp's image of #322:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp322.jpeg

14" LX200R @ f/10, L=4x12' RGB=4x10', STL-11000XM, Paramount ME

Related Designations for ARP322

ARP323

Arp 323 is part of Hickson 98 or maybe the entire group, sources vary. In any case, it is a galaxy group in western Pisces about 345 million light years. The bright pair is NGC 7783. Some catalogs show them as 7783 and 7783A while others say 7783A and 7783B or like NED NGC 7783 NED 01 and NGC 7783 NED 02. All left to right. In the MCG catalog, they are MCG +0-60-58 and MCG +0-60-59. Though the Kanipe-Webb book shows the western one as 7783 and the eastern as MCG +0-69-59. All very confusing. In the Hickson catalog, they are 98A and 98B respectively. The galaxy to the north is MCG +0-60-60 or Hickson 98D with the southern one below a field star being NGC 7783C or Hickson 98C. I'll use Hickson letters as they are something most agree on.

Hickson 98A is listed by NED as being SB0. 98B is S0 with 98C being just E and 98D as Sc or S0^+?. This latter galaxy isn't a true member of the group it seems as its redshift puts it at nearly twice the distance of A and B at 650 million light years. C's redshift shows 354 million light years which is close enough to be a true member of the group. There's a 5th galaxy in Arp's image, just southwest of C. It is SDSS J235412.56+002113.3 with no redshift or classification data given. Is it a member of the group? Maybe, as a similar galaxy that apparently is a member is seen to the upper right of the bright star above Arp 323. It is SDSS J235402.45+002723.7 at 360 million light years. See the annotated image for it and other objects in the field, especially asteroids. Galaxies are noted by G and their distance in billions of light years, quasars by Q followed by their distance also in billions of light years. The label is just to the right of the object unless I had to move it because of problems. In that case, I have drawn a line to the object. Two lines denoting the faint asteroid's start and stop points. All were moving east to west, left to right.

Note the long tidal tail descending to the southeast of Hickson 98B. It isn't mentioned by Arp nor did I see it on any image of this group I saw on the net. I've not done an exhaustive search but so far I find no mention of this "spike" anyplace I've looked. It barely shows in the POSS 2 plates if you enhance the heck out of the FITS version. It shows better on the Sloan image. After despiking Arp 192 have I now spiked Arp 323? It came as a complete surprise to me when I was processing the image. I came close to processing it out as a ghost image of some sort but it is real. My attempts to bring it out likely have it more sharply defined than it really is. Yet another to be retaken with far more imaging time in a few months.

The reddish oblong blur coming up from the bottom left of center is due to a 5th magnitude M5 star a bit out of the field of view. Enhancing the tidal plume also enhanced it quite a bit. I've toned it down considerably but couldn't eliminate it totally.

This image sets my personal record (Edit: since broken) for the number of asteroids seen in one image. I found 12 known ones down to magnitude 20.3. You'll need a monitor that can see deep into the black to find them all. In order of brightness they are:

Number Designation Magnitude
(47428) 1999 XK172 16.3
(105177) 2000 OA27 17.4
(58662) 1997 XJ2 17.6
2009 QR51 19.2
(60164) 1999 UF28 19.5
(125650) 2001 XV68 19.5
(182255) 2001 FM108 19.5
2005 SL88 19.5
2009 QJ58 19.8
2007 DE113 20.0
2006 UR118 20.2
2005 UK299 20.3

There appears to be the 13th asteroid, it is unknown to the Minor Planet Center. Unfortunately, this was taken in September 2009 and I only found it when I first looked at the luminance data in May 2010. So it was impossible to follow up on it. It is number 7 that I've found too late for follow-up. I had to go back and count them as I had been just guessing before. I've marked it with a question mark on the annotated image.

Magnitudes are estimates by the Minor Planet Center and may vary slightly from what they appear to be in my image. Color may be involved as my chip is blue sensitive so those that are red will appear dimmer than they really are in the luminosity image.

The SDSS image is attached with the tail showing faintly after I enhanced the image more than they did. I can't imagine this is a reflection of some sort. Though their image has its share of nasty reflections! For both of us to have the same reflection is too much to swallow. I've attached the SDSS image as well as mine and the annotated image.

Arp's image:
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp323.jpeg

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

Related Designations for ARP323

ARP324

Arp 324 is a chain of galaxies in a western corner of Hercules right on the border with Serpens Caput. It is located in the corner I call the realm of Abell galaxy clusters. As there's a line of 3 them with Abell 2147 at the south end. 2152 and 2151 are the other two, 2151 is the famous Hercules Galaxy Cluster. In fact, Arp 324 is almost at the center of 2147 cluster which is about 475 million light years distant. Arp put Arp 324 in his Group character: Chain of galaxies category. How many he saw in the chain I don't know. Some sources say 6 some 9. Arp's comment on the group: "Diffuse elongation of E's along line joining them." I think he is referring to the two main ellipticals which seem to exist in one diffuse, very elongated halo. Whether this is real or a line of sight illusion I don't know. I found nothing on this question. In any case, such elongated halos are a pretty good sign that these halos are tidal in nature. Not easy to pull stars from such massive elliptical galaxies so I assume it was these two interacting that caused these tidal features. The northern galaxy is classed as cD:E+ which is a rare type of extremely large elliptical galaxy usually found to be anchoring a galaxy cluster, which is exactly what it is doing. It is known as UGC 10143. The smaller southern one is PGC 056770 or MCG +03-41-051 and is classed simply as an E3 galaxy.

I really doubt this is a true galaxy chain but more a line of sight apparent chain of random galaxies in the cluster. Some of which, like the two big ellipticals and III Zw 075 below are interacting pairs.

Between the two main elliptical galaxies is a "cute" ring spiral galaxy with two fine arms coming off the ring. It is UGC 10143 NOTES01 or PGC 056777. It is a puzzle to me. Everyone considers it part of the chain. Here's a typical comment on it: "Compact red object with a faint envelope. This is a component of a chain (connected by a luminous band) of which the compact galaxy III Zw 075 is also a member." By red they mean infrared which I don't pick up. So it is more blue-white in my image. The problem is its redshift is considerably greater than that of the others putting it about 600 million light-years from us, 125 million further than the Abell Cluster that contains Arp 324. Sometimes a galaxy can pick up high speed due to the gravitational interaction with its cluster neighbors. That may explain it or it may not be a member of the group. I'm leaning toward the latter. It is quite obviously classed as SAB(r)ab.

III Zw 075 is the pair of elliptical galaxies below the ring spiral that are only 6" apart. Each has a slightly different redshift. I don't know why the note above implied it was a single galaxy. They appear to be a pair of interacting compact dwarf spherical galaxies in the Abell cluster. They seem to exist in a common envelope of stars though this may be an illusion.

At the bottom of the "chain" is a flat edge on spiral. It is UGC 10143 NOTES03 or KUG 1559+160. It is nearly impossible to find a catalog that includes all of these. Several include most, however. Like the ring spiral, its redshift is a bit out of line with the Abell cluster. In this case, it is about 75 million light-years closer by its redshift than Abell 2147. Since most cluster galaxies are elliptical I'm leaning toward this one not being a member as well.

Another spiral like galaxy "in the chain" is 2MASX J16021582+1557252. It is between the upper large elliptical and the ring spiral. Its northern arm seems far bigger and brighter than the southern. It might be two superimposed galaxies though NED and SDSS only list the one at in this immediate area. It, like the other spirals, has a redshift that doesn't fit the two main ellipticals for Abell 2147. It is about 100 million miles beyond them based on its redshift.

This covers the basic 6 galaxies in the "chain". While other sources list more I'm unable to identify them with any certainty. Some are listed by their MAC entry. The only listing of this catalog I have is accurate only to about 1 minute of arc in Declination and 15" in RA. Another PGC 56783 is non-existent in all of my sources. As best as I can determine at least two of these are referring to the little interacting trio of galaxies above the two major ellipticals and a bit west. From south to north they are SDSS J160214.00+160111.2, SDSS J160213.92+160127.2 and SDSS J160214.72+160127.5. Redshift data shows the first two are members of the Abell 2147 cluster. I have no data on the third member, it appears to be involved with the halo so probably is also a true member of the cluster.

Other nearby likely members of the cluster are SDSS J160211.40+160021.5 down and right of the trio above (the two leftmost galaxies point to it), SDSS J160215.30+160220.1 fainter and above the triplet and beside a dim blue star, SDSS J160217.58+160010.6 a bright elliptical at the top of the halo about the northern main cD elliptical and SDSS J160217.96+160027.9 the faint round galaxy just above the last galaxy. Continuing north along the same line as the last two but further north than the triplet is the rather bright elliptical member of the cluster and maybe Arp's chain, SDSS J160219.55+160209.6. Most of the other ellipticals in the image appear to be members of the cluster as well. Though a few are far beyond the cluster yet are as big and bright as cluster members.

If you've been following my posts I've been noticing the SDSS often missed very blue galaxies. So the extremely blue galaxy west of Arp 324 caught my eye. It seems an exception because it was picked up by the SDSS as SDSS J160154.20+160016.7 and has a redshift that puts it in the Abell cluster. So not all of these super blue galaxies are not picked up.

Down near the bottom left of center is a very weird galaxy with a redshift of 510 million light-years and thus likely a cluster member. It is right beside a rather bright blue star to its east. It is classed as S0 but seems to have a very odd blue ring around it. NED's primary listing for it is GIN 464. Blow up the image to see the ring detail.

Trying to do a typical annotated version of this image is virtually impossible. I'd have labels on top of labels making a mess and taking me far more time than I have available. So I've just pointed out a few objects, not members of Arp 324 or Abell 2147 that caught my eye. Objects like SDSS J160143.48+155706.3, a quasar at 12 billion light years shining at magnitude 21.3. A question mark indicates a galaxy not in NED that I think should be as far dimmer galaxies are included.

For those who have been asking the limiting magnitude of this image isn't as deep as I'd have liked, humidity cut down transparency. It is about magnitude 22 for tiny compact galaxies, 22.3 for stars and about 21.8 for fuzzy galaxies. All these are measured in green light.

Arp's image:
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp324.jpeg

14" LX200R @ f/10, L=6x10', RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP324

ARP325

Arp 325 is a chain of galaxies, one minute of arc long, in very southern Aquarius. There is very little on these. No catalog I could find lists them as separate galaxies. Most just number them 1 through 5, usually north to south rather than in RA order as most other such groups are numbered or lettered. Best I can do is either say they are VV 167 or MCG -04-52-014 and number them NED 01 through 05 top to bottom. I wish I could tell you more about this chain but I can't. I find only one redshift measurement of one of the galaxies in the chain. It is obviously wrong and NED says the same. It shows it coming toward us when it's quite obvious this is a very distant chain and thus would have a high speed away from us not a small one toward us. Neither Hubble nor SLOAN has examined this field. Arp had no comment on this field either. The Rodney Dangerfield of Arp galaxies it would appear.

This is by far the most southerly object I've tried to image. At -21 degrees it is well below my -15 degree cutoff. But the night was super steady giving me a chance. Still, the result is about 4" seeing but compared to the 8" that's normal this low that is darned good. I can't image it at its highest point due to the Meridian Tree which blocks that part of the sky. it was only about 14 to 18 degrees above my horizon when imaged, Some of this time part of the aperture was blocked by the wall of the observatory, blue and green data suffered most from this. If I'd been thinking I'd have taken the Red lowest since that low I lose a lot of blue and some green light but dummy did it backwards. This made color balance very difficult. There was no G2V star in the image (they are rather rare) nor could I use my normal formula for calculating the correction as I didn't know the light lost to the observatory wall. So this is a WAG beyond all reason. Still, it looks OK, just don't go saying these colors are right! I probably should have used this super night to take something high that could have used 0.5 pixels. In fact, that was planned for the next object. But the seeing didn't hold so I blew that one. But did get an Arp I didn't expect to ever image so something came of it at least.

There's little data on the rest of the field. One of the few galaxies with redshift data is west and a bit south of Arp 325. It is near the western (right) edge of the 1.5x cropped image. It is 2MASX J22060492-2106160 or LEDA 832620. NED shows it to be about 780 million light-years distant. There are two other galaxies at this distance in the image and another just off the bottom center of my image. All are similar to the galaxies in Arp 325. Could they all be part of the same group of galaxies? If so that would give a distance estimate for the group. The other chains like this one in Arp's catalog are all made up of similar elliptical galaxies of the same color. Here the northern and southern galaxies seem bluer and much smaller in angular size. I don't know what, if anything, this means.

I've attached a rather sparse annotated image showing them as well as one quasar. The quasar is magnitude 19.0, wavelength unknown, normally that would be quite bright on one of my images. It is rather dim in this one due to atmosphere extinction that low in my skies. I'd have liked to have added exposure time but first, the Meridian Tree objected (it blocks 2 hours around the meridian then the clouds seeing did. Never had a night of sufficient seeing after that to get more data. With so little data on the field, I can't but guess at my limiting magnitude. So I'll guess at about 20, over 2 magnitudes lost over a normal image. I wonder how much more there is in this field I missed.

Arp's image
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp325.jpeg
Notice how he was able to easily separate the northern galaxy from a star below it. This separation is barely visible in my image due to the seeing so low in the sky.

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

Related Designations for ARP325

ARP326

Another twofer deal on Arp Atlas entries. Most of them are completely unrelated objects that happen to be in the same field. Not this time. Arp 33 is part of Arp 326. Arp 326 is in Arp's category, Galaxy groups, chains of galaxies. The chain is located in Virgo right near the southwestern corner of Bootes. As can be seen in the annotated image this isn't a real chain but consists of galaxies of at least 2 different groups. Since redshift data is available for only 3 of the 7 galaxies Kanipe and Webb consider part of the chain its hard to determine what is really going on here. The chain members, as defined by Kanipe and Webb are (from north to south):

MAPS-NGP O_559_0677185 530 mly
CGCG 045-052, Spiral at 530 mly
SDSS J133727.40+063044.4 Not in Webb/Knipe's list
MAPS-NGP O_559_0677872
UGC 08610, Sa at 530 mly
MAPS-NGP O_559_0792305 520 mly
ARP 33/UGC 08613, SB at 340 mly
LEDA 214126, E? 340 mly

The classification of LEDA 214126 seems way off, Looks pretty much a spiral to me. For this reason, I left the classification off of the annotated image. UGC 08596 at 320 million light-years, classed as simply S and UGC 08623 classed as Sd at 340 million light-years. It is seen edge-on and is extremely flat. So flat it made the Flat Galaxy Catalog. It would appear these two are likely members of the same group as Arp 33/UGC 08613. Why Kanipe and Webb left out SDSS J133727.40+063044.4 I don't know. It is slightly brighter than MAPS-NGP O_559_0677872 just below it. While I identified MAPS-NGP O_559_0682366 NED had little on it. Just seemed big and bright enough to deserve mention. It looks like a nice face on spiral but NED omits a classification for it.

This brings us to Arp 33. While a member of the Arp 326 "chain" it made the Atlas under the Integral Sign category. It is a bit better integral sign than most of the others in that category, some of which require a lot of imagination to see as that math symbol. NED considers Arp 33 to also include LEDA 214126 which is also part of the Arp 326 group. Arp did include it in his image of Arp 33. The VV catalog considers UGC 08613 to be 4 galaxies; VV 6a through VV 6d. NED, however, says these are just parts of the galaxy. Something likely drew Arp 33 out into the integral shape. VV 6c and d seems a possibility. UGC 08596 shows a rather distorted arm on its east side and is also a possible cause of Arp 33's distorted shape.

NED and the Sloan survey identify a lot of other objects around Arp 33 that are similar to the VV objects. None of them are listed as being part of the galaxy, however. I've identified a few of them. It would get too crowded to identify them all. How some are part of the galaxy and the rest not I haven't figured out.

The image contains three asteroids. West to east (right to left), they are (102745) 1999 VZ111 at magnitude 18.2, 2006 ST289 at a very optimistic estimated magnitude of 19.8 and one not yet known to the Minor Planet Center. I did it yet again. Imaged an asteroid but discovered it a year too late to do anything about it so it is still undiscovered. It was taken April 7, 2010 and not processed until now. I do have to clean up this backlog somehow.

The 200" had sufficient field of view to do the entire group with its corrector lens in place. These online images are not made from the original plates but from first generation prints, Arp processed to bring out the detail he was interested in.

Arp's image of Arp 33
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp33.jpeg

Arp's image of the group Arp 326
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp326.jpeg

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

Related Designations for ARP326

ARP327

ARP 327, also known as Hickson 34, is a small group of 4 galaxies headed by NGC 1875, a very large E2 galaxy with a possible AGN (Active Galactic Nuclei). Its redshift puts it at about 410 million light years. The other members have slightly different redshift distances but this is likely due to interaction among themselves. Since NGC 1875 is the big gorilla of the group I'll assume it is little bothered by the companions and thus its redshift is the best indicator of the group's distance.

The other galaxies in the group, north to south carry the same designation in most catalogs, just that they are numbered or lettered west to east which also happens to be north to south. The PGC catalog does list them separately so that's what I'll use for the other three. North to south, they are PGC 17173 an 18th magnitude S0 galaxy, PGC 17175 a 17th magnitude SBd galaxy and PGC 17176 a 17th SA0 galaxy. It is PGC 17176 that seems most torn up by the gravity of the system.

A note at NED says this about the system:
The four galaxies of the group form a characteristic chain. This kind of configuration is frequently found in compact galaxies groups and is easily explained by the N-bodies simulations of clustering (White et al. 1987) which often produce filamentary structures.

Arp did classify this group under his classification "Group Character: Chains of galaxies. This was long before the paper explaining them.

There appears to be a possible 5th member of the chain, much fainter and not nearly as red. It is HCG 034:[RHF91] 02 per NED. Since HCG is their notation for Hickson Compact Groups they must consider it part of Hickson 34. Though there's no redshift data to determine if it is really a member or just a line of sight interloper. Its different color bothers me. Arp apparently didn't include it in Arp 327. In fact, he didn't include NGC 1875 in his group! His description is; "Three distorted galaxies in general line toward east." Thus he is leaving NGC 1875 out of the chain for some reason. Probably because it isn't distorted though I don't see much if any distortion in PGC 17173 either.

Unfortunately, the night was poor when I took this with my seeing a bit worse than 3". I needed a much better night to get much detail. I'll have to try again next winter.

The red galaxy NE of Arp 327 with its core offset to the right side is 2MASX J05215739+0643182 which appears to have a redshift distance of just under 400 million light years. So it could be related to the galaxies in Arp 327.

The largest galaxy SW of Arp 327 2/3rds of the way to the lower right corner is CGCG 421-036. It is a bit over 400 million light-years away so again, likely a member of the same group. Even closer to the corner not far from CGCG 421-036 is 2MASX J05205314+0633047. It is at the same redshift distance as CGCG 421-036. Continuing due west almost to the edge you come to another galaxy at this distance, 2MASX J05203488+0633083. Continuing west and north a bit is a galaxy mostly off the image but its eastern edge is seen just poking into the image above a pair of equally bright stars. This is UGC 03291 also at the same distance. So it appears the group that Arp 327 is part of is quite large and extends off my image to the west. Something I suspected so put it a bit east of center but not as far east as I should have.

Since the SDSS hasn't surveyed this area yet, there isn't much information on the few other galaxies in the image. Many are apparently anonymous.

Arp's image of the chain, including the two galaxies he excluded, is at:
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp327.jpeg
He had much better seeing than I did. I believe this image was taken with a somewhat blue sensitive emulsion, likely 103a-D coupled with a yellow filter. A combination he seemed to like I've recently learned. Why I don't quite understand. My guess would be, of the choices available to him, it best matched a visual representation. It would tend to even out the red of population 2 stars and the blue of population 2 stars giving a more even response across the spectrum. That's my guess, I've seen nothing on it.

14" LX200R @ F/10, L=4X10' RGB=2X10'X3, STL-11000XM, Paramount ME

Related Designations for ARP327

ARP328

Another Arp pairing

Arp 328/Hickson 72/UGC 09532. This is a chain of galaxies located in Bootes. All but one of the galaxies are about 600 million light-years distant, the other nearly twice as distant and thus not a member. Before going further and looking only at the full or cropped image, see if you can determine which is the odd galaxy out. It may not be the one you think. Arp put this group his class for galaxy chains and had this comment: "6 galaxies more or less in line; center one has semi-stellar companion." There are 7 in the chain including the sneaky interloper. Hickson also includes only 6 but one he includes is the "fraud". NED shows 7 galaxies for Arp 328 while Arp himself limits it to 6 as does Hickson. Both leave out the most southern. Yet one note at NED reads: "With respect to the original Hickson list we have included the amorphous object g which clearly interacts with galaxy c. This is the one I've marked as VV164g. G is blue and does seem to have a bulge toward c but I'm not sure this is sufficient for it to be clearly interacting. This brings us to the "semi-stellar companion" I assume he is speaking of D. While in my image it may appear to have two cores of about the same brightness the SDSS image clearly shows the southern one to be a star. There is a slight brightening north of the core, best seen in the Sloan image but it isn't semi-stellar. Nor can I see much of anything in the burned-out core of Arp's image as it is on the website. But E does show what appears to be a distant galaxy through its disk on the east side. Could this be what Arp refers to? It does show in his image. If the possible 7th galaxy is included then E would be in the center. I've found nothing to decide this issue.

Below and left of component g is yet another compact golden elliptical like galaxy, SDSS J144759.73+190202.0 at 18th magnitude. No one considers it part of the group. Nor is any redshift data available for it. There are several small galaxies about component A as well. Are they satellites of A or distant line of sight galaxies? Probably the latter though a note at NED considers this possible.

A is classed as S0, B as S0?, C as E2, D as SB0, E as Scd, F as S0 and G as S0?.
___________________________

Arp 47/MCG +03-38-014 is classed by Arp under Spirals with low surface brightness companions on arms. I suppose that refers to the little galaxy off the north arm that curves back sharply. That galaxy is 20th magnitude SDSS J144715.24+185134.8. No redshift is given so it's unknown if it is truly a companion. There is the very obvious galaxy to the west of MCG +03-38-014. It is 16.6 magnitude NPM1G +19.0402. NED and other catalogs consider these two a pair. In fact, NED lists these to under Arp 47. Seems way too bright to be the companion on the arm Arp refers to. So which is it? I still think it the one that definitely appears to be on the arm and certainly is faint. Unfortunately, NPM1G +19.0402 doesn't have a redshift value either which doesn't help us any. NED makes no attempt to classify this obvious spiral or either "companion".

Arp's image is one of his poorest. This isn't Arp's normal work. Makes me wonder if some night assistant took this data rather than Arp himself. He may have had quirky ideas bordering on crackpot in later years but his telescope work was very precise. One possibility is Arp did, like I did, and took both of these with one image. This would have pushed the Winn Corrector to its limits and maybe beyond. Arp 48 may have been right at the edge of the image where the Winn Corrector couldn't quite handle the prime focus distortions. The stars radiate away from the position of Arp 328 like it was centered and this one just too far away for full correction. The elongation of the star in the lower right corner seems greater which fits this idea. I can't see Arp guiding this poorly.

There's no redshift data on anything in the field other than these two objects. NED lists several thousand galaxies in my field but except for these two Arp's, there's nothing on it. Note however that both are at the same approximate redshift distance and thus quite likely part of the same group.

Arp's image of 328
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp328.jpeg

Arp's image of 47
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp47.jpeg

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

Related Designations for ARP328

ARP329

Arp 329 aka Hickson 55 is yet another chain of elliptical galaxies Arp logically put in his Group Character: Chains of galaxies class. Also known as UGC 6514 1 through 5. This is a rather puzzling chain. 4 of the galaxies show a redshift that puts them at about 700 million light-years with only a very small variation, smaller than normally found in such chains in fact. But then there's that oddball one. Can you spot it?

Most catalogs list these under one number with either a letter A-E or number 1-5 designating which is which. Since these are assigned in RA order it is kind of confusing. Only the PGC catalog gives them separate numbers but again in RA order. Top (north) to bottom they are PGC 035574, PGC 035576, PGC 035575, PGC 035573 and PGC 035572.

The odd galaxy out is the second from the top, PGC 035576. It is the smallest and bluest of the bunch. Its redshift puts it a bit more than twice as distant as the other four at about 1.5 billion light-years. No wonder I picked up so little detail. So is it just a line of sight coincidence or is it really much closer. Arp would likely argue for the latter while most other astronomers the former. To me, its different color and its smaller size would cause me to vote with the coincidence theory. Oddly, Arp seems to have no comment on this one. Though he does state in general that he considered such a coincidence to be a 1 in 10^4 to 1 in 10^6 chance level. I don't understand how he came up with this, however. Sounds to me to be calculating the chance in a particular group for such a coincidence rather than the chance that some groups will have such a coincidence. I know I have at least one math prof on the list, maybe he has some ideas on this. Arp also considered chains even without an oddball to be highly unlikely due to chance. Now we know that in small groups gravity will tend to cause them to fall into such chains. Also, remember we are seeing this in 2D, we really can't say much about the depth involved. Though the math now says real chains should be about as common as we find them to be.

Very few of the galaxies in the image are in any catalog except the MAC which gives little useful information. I find redshift data mostly missing except for the Hickson group and one other.

The elliptical above and right of Arp 329 is 2MASX J11314875+7054045. While it is the same color and about the same size and brightness of the biggest member of the Arp group, without redshift data I can't tell if it is a member or not. The blue spiral to the east (left) of Arp 329 is MCG +12-11-033 at magnitude 17. The blue galaxy near the bottom edge a bit left of Arp 329 is CGCG 334-036. East (left) of this galaxy is the tiny S0 galaxy 2MASX J11340329+7035372 at about 125 million light-years (much closer than Arp 329). The spiral to its upper left is 2MASX J11344815+7039213. It appears there's a distant group of galaxies behind it but I find nothing on them other than a couple are also IR galaxies with no redshift data. The glue blob of a galaxy west of the last galaxy and above the previous one is PGC 2737488 at 18th magnitude. I could find no entry for the blue galaxy above and a bit left of Arp 329. I didn't check the MAC, however.

The elongated, very bright, yellow star near the left edge is Struve 1551, a double star the brighter is G5 and thus nearly white since I balance to G2 being white. Its companion appears somewhat yellower. They are separated by about 7" and thus overlap due to the heavy stretch applied to the image.

Arp's image
http://nedwww.ipac.caltech.edu/level5/Arp/Figures/big_arp329.jpeg

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

Related Designations for ARP329

ARP330

I'd been hoping for a really good night to image this group. Finally, we had one and the northern lights turned on so bright you could read a newspaper. I might as well have been imaging from downtown Chicago. I ended up throwing out a third of the luminosity images and half of the red, green and blue images keeping the best two. Still, I had super nasty gradients. Normally my background would be about 250 counts out of 65,000 but this image was 14,000 at the upper left, falling to 8,000 near the lower right but then a huge ray or something popped up taking the very lower right corner to 39,000! Thank goodness for GradientXTerminator. It took several applications using various techniques but I ended up with a usable but not great image. My biggest worry is color balance after removing so many gradients. But I think I'm rather close to being correct even though most of the galaxies seem overly reddened.

Arp 330 is in Arps class: Group Character: Chains of galaxies. One note describes the group: "In a beautiful interconnected chain of six red compacts [faintest m(pg) = 18.5] and one blue crescent-shaped post-eruptive compact: m(pg) = 16.5.

From North to south the 7 galaxies are:
2MASX J16491727+5327127, no classification or red shift data, mag 17
2MASX J16491727+5327127, E0, 350 million light-years, magnitude 17
2MASX J16491130+5325573, E2 pec, 410 million light-years, magnitude 17
2MASX J16491152+5325113, E1, 410 million light-years , magnitude 15.6
2MASX J16491274+5324183, SBbc pec HII, 364 million light years, mag 16
MCG +09-27-093 mag 19
2MASX J16490837+5323334, E2 pec, 400 million light-years, magnitude 16
2MASX J16490401+5322254 no data

OK, that's 8. I included the last one as I'm not sure if it or MCG +09-27-093 is the 7th galaxy. 2MASX J16490401+5322254 shows well in Arp's photo and is a bright IR galaxy while MCG +09-27-093 is nicely tucked between two obvious members but barely shows in Arp's photo. So which is the 7th member most sources speak of?

The very red, large, barred spiral galaxy to the upper left corner is 2MASX J16501529+5333072, so yet another IR galaxy. It is apparently part of the same group at 400 million light-years. Its red color seems to fit the group as well. But it must be a much larger galaxy.

Within the main group is the lone highly distorted spiral. It isn't red at all. In fact, it has a rather large blue tidal area between the two larger elliptical's halos. The blue area is faint but seems real. Thus it must be interacting with the others and its redshift a poor indicator of distance.

The only other galaxy with a redshift in the image is 2MASX J16471357+5333403 in the upper right corner. It fits right in with the others with a redshift distance of 380 million light-years.

Going NW of Arp 330 about 7 minutes you come to the center of the Zwicky galaxy cluster ZwCl 1647.6+5337 NED shows it as having 157 members in a diameter of nearly 2 degrees, far larger than my image. It shows a redshift distance of -- you guessed it -- 400 million light-years. It appears nearly all its members are very red.

I've identified many of the galaxies around Arp 330 on a separate image. You might wonder about the galaxy at the top near a bright star. It wasn't in NED or SIMBAD. The Sky identifies it as PGC 281743 at magnitude 16.5. Apparently, it is not an IR galaxy so was missed by the 2 micron survey that picked up most of the galaxies in the image. What about the SHK galaxies? SHK stands for Shakhbazian Compact Groups. Number 16 on the list includes Arp 330 and surrounding galaxies. Most of the 2MASX galaxies are also members of the SHK 16 group. Those that are members of SHK 16 but not 2MASX cataloged galaxies I identified by their SHK 16 number. Arp 330 carries several other group designations such as CGPG 1648.0+5331 and I Zw 167. Like the SHK group, these may contain more galaxies than Arp did, I didn't check this, however.

Arp's image of Arp 330 is at: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp330.jpeg

Even with the problems of the aurora my image goes deeper than his which surprised me.

14" LX200R @ f/10, L=6x10' RGB=2x10'x3, STL-11000XM, Paramount ME

Related Designations for ARP330

ARP331

The Pisces Cloud is 29 galaxies in Pisces galaxy cluster though common usage seems to refer just to the C2 group which is Arp 331. How many galaxies Arp considered part of his chain seems to vary with the source. Most say the 8 listed below excluding 373, 375 and 388 but others say 12 or more. It just depends on when you stop counting and how far east or west of the bright vertical chain you venture. If those I list Seligman leaves out 373 saying it is too far west.

Hubble classed this group as "Group Character: Chains of galaxies". It is also known as Zwicky cluster 0107.5+3212. The chain is too large for the FOV of the 200" so the photo Arp uses comes from 48" Schmidt camera. It appears to be a very short exposure as it only picks up the cores of the galaxies making them look a lot further apart than they do in my image. Arp's comment: "Symmetry around large central galaxy." This may be a clue as to which galaxies he considered part of his object.

Galaxies north to south with discoverer and date of discovery. Galaxies north to south with discoverer and date of discovery. Independent redshift is noted by ind. RS indicates a redshift distance. Both are in millions of light-years.


NGC 379 S0 208 ind, 241 RS William Herschel September 12, 1784
NGC 380 E2 208 ind, 189 RS William Herschel September 12, 1784
NGC 383 SA0 LERG* 208, 220 RS William Herschel September 12, 1784
NGC 382 E, 234 ind, 226 RS Bindon Stoney November 4, 1850
NGC 387 (east of 382) no class no ind 202 RS Lawrence Parsons December 10, 1873
NGC 386 E3, no ind, 240 RS Bindon Stoney November 4, 1850
NGC 375 E2, no ind, 254 RS Lawrence Parsons December 1, 1874
NGC 385 SA0, 208 ind, 214 RS Bindon Stoney November 4, 1850
NGC 388 east of 385 E3, no ind, 235 RS Bindon Stoney November 4, 1850
NGC 373 E, no ind, 238 RS John Dreyer December 12, 1876
NGC 384 E3, no ind, 180 RS Bindon Stoney November 4, 1850

All carry this NED note:
Faint compact member of the Group C2 of elliptical galaxies forming one of the four prominent condensations.

So what about that lone spiral above NGC 375 (UGC 679). Include it and you get an even dozen that some writers say is the count. Oddly the MCG catalog lists it as being NGC 375! Is it a member of the group though not mentioned by Arp? Looks like it may be. NED says it's likely about 214 million light-years away, only about 6 million more than the rest, and redshift puts it at 220 million light-years which is in close agreement as well.

The image is full of orange "stars" that are really galaxies. For instance just off the east end of the blue spiral are two of these star-like galaxies. One is slightly above and left, it is very orange. A bit closer and below is a yellow-white "star" that is also a spherical galaxy. I have no redshift or other distance indicator but suspect they are part of the same group, just smaller members.

I had to move the field further north than I wanted due to the 6th magnitude star. When I centered everything it was out of the field but sending in some nasty ghosts. The only way to get rid of the worst of them was to move it into the FOV. For some reason, my filters scatter more green and blue than red light so even though it is a K0 star it has a rather cyan halo from the excess green and blue. I didn't try to fix this.

Many galaxies in the image I didn't mention had redshift data. All of which indicate they are members of this group. Far more either had no redshift data or weren't in any catalog. This area hasn't been covered by SDSS.

NGC 390 is just one of two stars I've listed as a double star in the annotated image. Guillaume Bigourdan saw it on November 19, 1884 recording it as "very faint, very small, stellar. Unfortunately, while these two stars are nearby his position fits neither well enough to tell which he was seeing. Most likely the upper one so that's where I put the label. It itself is a double star which might have made it appear slightly fuzzy. Some say PGC 4021 further east and a bit north is what he saw. That, though, just stretches the NGC position too much. Certainly doesn't fit his stellar description either.

Arp's image with the 48" Schmidt telescope:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp331.jpeg

*LERG stands for Low Excitation Radio Galaxy

14" LS200R @ f/10, L=5x10' RGB=2x10'x3, STL-11000XM, Paramount

Related Designations for ARP331