ARP297

Arp 297 falls under Arp's category of galaxy groups, long filaments. It is located in Bootes. Its distance is a problem I'll get to. It is made up of several NGC galaxies, NGC 5752, 53, 54 and 55. When I looked at Arp's image of it I was puzzled by his comment: "Companion on arm has long tail extending westwards." The companion I assumed to be the galaxy seen atop the spiral in his image (to the left in mine) While an arm of the spiral went behind the "companion" I couldn't see that as being called a filament and it certainly didn't go west (up in Arp's photo). Then I started to image it. First 10 minute frame came in and there was a nasty reflection off to the west of the spiral. I moved the scope as that would usually stop such reflections and tried again. But there it was and it didn't move in relation to the stars. So it must be real. I looked at the GIF version of the POSS plates and saw a hint of something. I enhanced these and yes it was there though my "reflection" was much larger. I downloaded the Sloan image which showed it clearly and now I could see the real long filament Arp was talking about. I can't see but a faint hint of it in the scanned version of his photo but sure could in my frames and the SDSS image. I moved it back where it was for the first image and took 7 more. I didn't use the moved frame as it would result in the image being rather cropped by several minutes.

As I processed this image a year later I noticed something odd. The filament goes west-northwest then fades before appearing again going due west at A higher intensity. Not only that there appears to be a faint hint of it going further east than where it meets up with the west-northwest part. Also, the color is different. This bothered me (still does). Then I started to gather redshift data and things got really strange. The spiral, NGC 5754, has a redshift of 215 million light-years. The companion's redshift puts it at 214 million light-years. So far so good. Now note the odd large blob on the arm north and a bit east of the core of NGC 5754. That carries its own catalog entry which NED labels as PoG meaning it's part of the galaxy. But its redshift is more than twice as great putting it at 439 million light-years. Oops, that doesn't compute. Note it isn't blue as the rest of the arm is but more white. The blue arm fades out before reaching it in fact. Look back at the white part of the west pointing long filament that's the same color. It points right to the blob! I have no idea if this means anything or not but it sure is interesting! I find no entry for the filament so can't provide a redshift.

Now consider the other two galaxies of the "group". NGC 5755 is the highly distorted spiral and its redshift puts it 443 million light-years away. About the same as the blob. The fourth galaxy is NGC 5753 to the northwest of 5755. It's has a similar redshift that puts it at 442 million light-years. These are virtually the same as the blob supposedly part of NGC 5754 yet at the distance of 5753 and 5755. Yet I find no papers that see any issue here. Not even a mention of the redshift differences. To me, it is a really interesting puzzle.

At the top, a bit right of center, there's a galaxy cluster marked by one enormous galaxy if NED's data is right. The cluster is MaxBCG J221.37379+38.60317 and contains 15 galaxies in an unknown area that has a photographically determined distance of 1.9 billion light years. The core galaxy SDSS J144529.70+383611.4/2MASX J14452968+3836117 has a redshift distance of 2.0 billion light-years. This is where I have a big problem. If that's correct that is one tremendous galaxy. By my measurement, the galaxy is a bit over 53" of arc across which at that distance is over a half million light-years. I had never considered a galaxy of that size possible. NED shows it at magnitude 16.8 so there's no chance of a misidentification though they show it as only 25 seconds of arc across. Still twice the size of our galaxy but not impossible. I can't see how they got that measurement, however. My image scale is 1.01" per pixel so you can make your own measurement. I have to believe something is wrong here, I just don't know what it is.

NGC 5752, NGC 5753 and NGC 5755 were discovered by Lawrence Parsons on April 1, 1878. NGC 5754 was discovered by William Herschel on May 16, 1787. It isn't in either of the H400 programs.

This is a reprocess of my old data which shows a bit more detail than the original processing did. Also, I'm running these images south up rather than my normal north at the top. Just seemed more pleasing this way.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp297.jpeg

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

Related Designations for ARP297

ARP298

Arp 298 is a pair of interacting galaxies about 200 million light-years distant in the constellation of Pegasus just northwest of the circlet of Pisces. The northern galaxy is IC 5283. It shows a nice tidal plume off to the west-northwest. Unfortunately, due to a major blunder by an imager who will remain nameless this image was taken like they do it in the movies -- with the lights on in the observatory. I don't mean the red 10 watt ones but three 60 watt white bulbs! This increased my noise level greatly and cut my limiting magnitude from the common 22.5 to 23 by about 1.5 magnitudes. Actually, I thought this image lost when I realized what I'd done but it's amazing what GradientXTermanator can do!

My image also seems to show a faint plume to the north from IC 5283 coming off the eastern end. Unfortunately, it may be just noise due to the lights being left on. Though I do see hints of it in the Hubble image when seen at lowest resolution. IC 5283 is classed as SA(r)cd pec? by most sources I checked. A few say it may be a Seyfert 1 galaxy. It certainly is a mixed-up galaxy. If it has a core it is shifted, "sloshed?", to the eastern end and highly distorted by its encounter with its companion. So I found it rather surprising when one source claimed they are not interacting galaxies. I stopped reading at that point. Probably shouldn't have. Maybe it was a misprint.

There is definitely a spray of stars between IC 5283 and its larger companion NGC 7469. NGC 7469 is classed as (R')SAB(rs)a. While I found few papers on IC 5283, everyone and their uncle have apparently written something on NGC 7469. A search turned up an endless stream of references! It seems it is a prototypical Seyfert 1 galaxy so has been studied every which way -- though the field is out of the Sloan survey area so they haven't covered it. Its core is surrounded by a ring of massive star formation that appears rather continuous in my image except for a few brighter areas. That's an illusion due to low resolution. Hubble shows it to be made up of dozens of bright star forming regions. From this ring, there's an apparent outer ring. It is really two spiral arms that overlap making what appears to be a continuous ring. Even my lower resolution shows the ends of the arms. One paper said the star forming knots were more common on the northern side that faces IC 5283 and were a good indicator of the interaction between the two. I agree the interaction likely helped form these regions but to say that is why more are on that side just doesn't fly to my way of thinking. Galaxies rotate. Even a "new" region like these have likely made one or more trips around the galaxy in this time. This would make it mostly coincidence that we happened to catch things where more were on that side of the galaxy. Differential rotation would quickly destroy any organized pattern. It's likely these have been interacting at least a half billion years to create the plume and spray of stars we do see, plenty of time for star forming regions of NGC 7469 to be randomized. The inner ring certainly shows a rather even distribution of star forming regions.

Arp classed this pair under double galaxies with the comment: "Absorption, knot. Note apparent re-entrant spiral arm on southern galaxy." I'm not sure what he sees as the "re-entrant spiral arm." The more I look at Arp's photo as well as the Hubble image I am wondering if IC 5283, the northern one, might not be two interacting spirals itself. I didn't find any hint of this possibility in the literature, however. NGC 7469 was discovered by William Herschel on November 12, 1784 but is in neither H400 observing program. IC 5283 was found by Guillaume Bigourdan on September 4, 1891.

There are two asteroids in my image or should be according to the minor planet center. The brighter is (105526) 2000 RQ26 at magnitude 18.0. It is easily seen as a short slightly downward slanting streak NE of the bright star that's NE of Arp 298. The other is listed at magnitude 19.5 and should be visible but I show nothing in that location. It could be it was lost in the gradient from the observatory lights. The data for its orbit is a bit skimpy based only on a 34 day arc. Also, it was discovered in 2004 yet hasn't made one orbital rotation since discovery so may be far fainter than the predicted magnitude. I usually can go at least a magnitude fainter than this in the FITS image so this is a bit of a mystery. It is 2004 JR45 for those wanting to try and find it.

In preparing the annotated image I came across CXOMP J230252.1+085520 an X-ray object discovered by the Chandra X-Ray Observatory Multiwavelength Project. It is classed by NED as a Seyfert 1 galaxy. The kicker is that they put its distance at just over 12 billion light years at magnitude 21.3. Quasar maybe, a galaxy that size that early in our universe's existence? That's one heck of a Seyfert AGN! I have trouble swallowing that. But it isn't the only one like this in the image. At magnitude 21.2 is another Seyfert 1 galaxy found by Chandra that is listed at 9.1 billion light years, CXOMP J230252.2+084810. Note these are the magnitude in red light rather than green I normally use. My CCD is rather insensitive in red light. There are several others including some found by ROSAT. All are marked as Seyfert 1 galaxies with redshifts that seem far beyond anything I should be able to image if they are galaxies rather than quasars. All are marked on the annotated image with G? to denote my uncertainty. To complicate things further one ROSAT object, not pinned down by Chandra, has rather vague coordinates with a large error bar for its position. In that case, I've put a question mark after the distance to indicate this is my best guess as to the object based on magnitude and location in relation to the error circle.

While the field hasn't been covered by Sloan a surprising number of objects did have redshift data. NED lists 5 galaxy clusters in the image. One had a galaxy at the exact position listed. I've shown that one on the annotated image with a GC label. I couldn't really see any sign of the others so haven't marked them.

I can't explain the lack of identified objects on the eastern half of the image. Might be I hit the very edge of the surveys. Other than that I'm out of ideas.

Hubble's great image:
http://hubblesite.org/image/2286/news_release/2008-16

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp298.jpeg

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

Related Designations for ARP298

ARP299

Two smashups -- 5 galaxies -- What a mess that makes. While several pairs of Arp Atlas entries are close to each other in angular measurement these two are the closest. Though they are far apart in reality.

To me, this is a case of string cheese and a massive train wreck all in one image. Arp created a lot of confusion on this pair of entries when in some places he reversed them. There's also confusion on which galaxy is IC 694. More on that later.

Arp 296 is the string cheese part of the entry. It is a pair of galaxies apparently nearly connected by a long filament that appears to be drawn out from the lower galaxy. There's a counter filament going the other direction as well that is much shorter. The lower galaxy is SDSS J112850.64+583336.7, two minutes north is PGC 035345. NED classes the lower as S: pec and the northern as SB(r)ab and notes a lot of HII emission not seen in my image. Both are about 800 million light-years away. Are they really an interacting pair? Odd how one has severe tidal tails while the other is rather normal looking though its eastern arm suddenly becomes very faint and somewhat drawn out. Though I'd think we'd see more distortion than this from an interaction. Or is the arm weak because its stars contribute to the plume apparently coming from the lower galaxy? I didn't find any help in the literature. My search wasn't all that great however so if someone out there knows of some help here let us know. Arp's comment on the pair reads: "Long straight filament almost to attachment with arm of spiral." By spiral, I assume he means PGC 035345 as NED shows both as spirals.

Much nearer at only about 150 million light years, Arp 299 is a quite spectacular train wreck in progress. I didn't realize all the outlying plumes around it or I'd have used a lot more time on this image. Maybe later this year I'll get a chance to try and add time to it. I did take a lot more data but half of it was so poor I threw it out. The double data was an accident, I didn't realize the two Arp's were in the same field and imaged it twice, once on a very poor night. But you can barely see a north going plume that is rather narrow and eventually curves a bit left. Another, fainter one is seen to its west Below there's a bright wide and short plume due south with a far fainter and far larger plume to the southwest.

The identity of the two galaxies is very confused. Some sources say NGC 3690 is the western galaxy with IC 694 being the eastern member. In fact, most of the literature I saw says this but newer literature identifies IC 694 as the small galaxy to the northwest but still in the plume of the colliding pair. I'm going with this interpretation and have so marked the annotated image. For more on this see http://iopscience.iop.org/1538-3881/118/1/162/pdf/990040.web.pdf (PDF pages 22-23, Journal pages 183-184). Note that their discussion of the plumes matches my image as to the northern plumes (fainter one west of the main one is also visible in my image) but I see a much larger plume to the southwest than they show. More data will likely settle the issue.

NGC 3690 was discovered by William Herschel on March 18, 1790, but is in neither H400 program. IC 694 was discovered by Bindon Stoney on January 27, 1852.

Is IC 694 involved with Arp 299? Arp seems to have included it. NED does class it as a starburst galaxy with an active galactic nucleus, no other classification given. Its redshift distance is nearly 190 million light years. If right that puts it about 40 million light years beyond the train wreck. While it is remotely possible this difference is entirely due to a relative motion I find that a bit difficult to accept. It may have passed nearby a billion years ago at a distance great enough to not distort it but close enough to trigger the starburst and feed its black hole. A process that could be continuing today. But I doubt it had anything to do with the train wreck that is Arp 299.

Of the colliding pair, the western one is classed as SBm? pec by NED with the eastern one classed as IBm pec. How they detect a bar in either is beyond me. They both appear to be a bunch of bright star regions scattered about with what is left of the cores well off center.

The confusion continues with a pair of galaxies in the south-east corner of the image. I note in the annotated image the southern one (rather blue) as being 0.59 billion light years distant. NED is very confusing about this pair. In the position of the northern galaxy, they show 2MASX J11300711+5826154 with no distance. The blue galaxy is 13" of arc south-southeast of this galaxy. At about the position of the southern galaxy NED shows two galaxies as VII Zw 405 NOTES01 and VII Zw 405 NOTES02 with a separation of 3". While my seeing wasn't all that good I thought I should be able to see that lower blue one as a close double. Looking at the notes at NED several different sources say VII Zw 405 is a double galaxy with the northern one being red and the southern blue with a separation of -- 13" of arc. Their own notes would seem to say the southern blue object is just one galaxy. The position NED gives for VII Zw 405 matches the blue galaxy's position. Only the southern member has a redshift measurement. So who is right here I have no idea.

Low center there's a nice tight group of galaxies with the same red shift distance of 0.56 - 0.57 billion light years that are blue. One apparent member is somewhat redder but has no redshift data. I marked it with a question mark.

Hubble image of Arp 299 (its a tad better than mine):
http://www.spacetelescope.org/static/archives/images/large/heic0810as.jpg

Arp's image of Arp 296
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp296.jpeg

Arp's image of Arp 299
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp299.jpeg

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

Related Designations for ARP299

ARP300

ARP 300 is in his class "Group galaxies: Double galaxies. They are UGC 5028 and UGC 5029, right to left. But UGC 5028 is itself a double galaxy MRK 111 NOTES1 and MRK 111 Notes2 top to bottom. So we really have three. Or is it four? Note the thin needle "galaxy" to the lower left of UGC 5029. Oddly it isn't in the Sloan survey that I can find nor any other catalog yet quite obvious. Arp apparently mentions it in his notes when he says, "Note elongated feature pointing toward nucleus of larger spiral." Apparently, he didn't consider it a galaxy nor does anyone else. Sure looks like one to me. It likely is far in the background but without data that's only a guess.

Note there is yet another double galaxy in the area. Below UGC 5028 is a pair of very orange galaxies; VII Zw 280 NOTES04 (top) and VII Zw 280 NOTES03 (bottom). I find no redshift data on them but they too appear far in the background. Arp included them in his photo.

So how far away are the galaxies in Arp 300? The simple answer is about 180 million light-years. But this varies some by whose redshift you believe. Galaxies in a group orbit around a common center of gravity which gives them each a different redshift. When the group is small there's no good way of determining an average velocity. The dance they do can be very complicated to sort out. Individually, per NED the distances using 5 year WMAP data are: UGC 5029 181 million light-years, MRK 111 NOTES1 178 million light-years and MRK 111 NOTES2 185 million light-years. Note the cores of MRK 111 show quite different colors in my image. At first, I suspected the bottom one to be a star in our galaxy not a galaxy core but the redshift data shows that was very wrong.

There's a galaxy cluster candidate, NSC J092952+683500, in the upper left corner of my image. I see a bunch of very orange galaxies in that area. None have redshift data, however. So I don't know if they are the cluster or it is something fainter. The cluster is said to be 4 billion light years distant so if it contains some giant ellipticals they might be at least some of the orange galaxies in that area in my image.

The featureless blob of a galaxy on the right edge of my image is UGC 04998, a nearby galaxy only about 30 million light-years from us. So it is far closer than any other galaxy in the image. It is an Im galaxy.

These galaxies are located in Ursa Major not far from M81 and M82. That likely explains the galactic cirrus that appeared in the image much to my surprise. Most of it is at near background level so appears as background noise but for the ribbon running vertically through the image.

Arp's image is at:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp300.jpeg

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

Related Designations for ARP300

ARP301

ARP 301 is a pair of interacting galaxies in northwestern Leo about 300 million light-years distant. The two galaxies are UGC 6204 (face on spiral) and UGC 6207 the edge on spiral. Arp put them in is Double Galaxy class. Looks like it could have gone in his Wind Effects class to me. The plume on the east end of UGC 6207 that gives it that wind blown look doesn't have that appearance in Arp's image. Arp has no comment on this pair.

UGC 6204 is classed at NED as Sb? pec. Edge on UGC 6207 is classed as Sb? pec one place and SBb another. Arp made no comment on these. UGC 6204 does have three interesting knots in the arm that have been created by the interaction. The edge on also is full of blue knots. Wish we could see it from a better angle. UGC 6204 seems to have a double core. The SDSS sees the southwest (lower right) one as the main one apparently while everything else refers to the northeast one as listed at NED.

UGC 6207 has a blue knot just east (left) of the orange disk. The Sloan survey gives it a separate designation listing it as a separate galaxy. They give it a redshift that puts the object about 6 million light-years further away than UGC 6207. I really doubt that it really is a different object, however. There is a blue, maybe fuzzy, spot at the very end of the long tidal arm of UGC 6204 right where it begins to overlap UGC 6207. It's hard to tell from my image or Arp's if it is a star or star knot in UGC 6204. The Sloan image seems to show it is a knot. It doesn't list it in any way, either as a star or part of a galaxy. I will go out on a limb and say it is a knot below my resolution.

I've prepared an annotated image but many I'd like to have distance data on, have no redshift data at NED. There's a tight pair of apparently interacting red galaxies a bit over 8 minutes east of Arp 302. The western one with the plume is 2MASX J11103049+2416187 the one east and south of it is SDSS J111031.01+241612.9 but neither have redshift data. Further east and north is a galaxy with two wide faint spiral arms. It is 2MASX J11104138+2417298. North of it is KUG 1108+245. This catalog entry indicates it is an ultraviolet emitting galaxy. It is also known as the IR source 2MASX J11104153+2418248. So it is both an IR and UV emitting galaxy. This is interesting but again little more data is available for either of these galaxies.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp301.jpeg

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

Related Designations for ARP301

ARP302

ARP 302 is a pair of interacting galaxies known as UGC9618 located 460 million light-years away in the constellation of Bootes. Arp put it in his class: Group Character: Double Galaxies. Apparently, he missed the tidal star clouds around especially the northern member.

The southern galaxy is a Sc blue spiral. It shows some rather strong HII emission but isn't considered a starburst galaxy as it lacks the needed IR light. The northern member, however, is quite different. It is a red spiral classed at NED as Sb and is a LINER galaxy indicating its core is very active. It is classed as a starburst galaxy and does have strong IR emission showing active star formation. This is odd. Normally red spirals are considered dead spirals. Ones in which star formation has ceased so they are dying as all the new blue stars are long burned out leaving only yellow and red stars giving it a reddish hue. But here we have massive stars being formed though this is hidden to us by warm dust we see as IR light. I do note the very ends of its arms are blue. Usually, in a starburst galaxy, the majority of the star formation is in the core. These spirals are often barred spirals but this apparently isn't one of them.

While this field is covered by the Sloan survey NED shows no distances for any galaxies in the field beside the two making up Arp 302. Below Arp 302 is a tight trio of galaxies almost in a line. The two on the left look like one on the POSS plates but are separated by a narrow dark band in my image as well as the Sloan image. The right object is much bluer than the left but far smaller in angular size. Looks like a piece broken off the left piece but the color difference makes it obvious they are separate objects. I have no distance data so can't tell if they are really close together or not but at least NED does list them. The third member of the group just to their right isn't listed at NED but the faint 23rd magnitude galaxy beside it at the one o'clock position is. There are many interesting galaxies but about all I have on them is a magnitude estimate and their coordinates. Thus I didn't bother to prepare an annotated version.

I'd like to know more about the edge on spiral near the right edge of the image at the same level as Arp 302. It too is a red spiral and seems to have blue stars at the very ends of its arms. Coincidence? Or is it related to Arp 302 and had a run in with it in the distant past causing these blue ends? Wish I knew. There's just nothing much on these galaxies unfortunately Even Arp made no comment about them.

Normally I image at 1" per pixel binning the image 2x2. But this night seeing was far better than normal so I went to 0.5" per pixel by not binning. To keep the image size within reason for the internet I only downloaded the center one quarter of the image by area. When seeing permits I often enlarge the image to 0.67" per pixel. No need here as it already is at 0.5" per pixel. Still, the stars are very tight. Many only 1.2" to 1.4" FWHM. This is likely my highest resolution Arp image to date, slightly better than Arp 149 taken the previous night. But like the previous night, the good seeing didn't last. I'd hoped to take 12 L images but after only 7 seeing went very bad. So bad in fact I had to shut down. Color data was taken binned 2x2 the following night. I'd hoped I'd be able to get more L data that night but seeing was 2.5" (about normal) and far from what I needed to go to the 0.5" pixel. I never did get more luminance data. So the image is noisier than I'd like but the detail makes it worth it.

See Arp 177 for later and better images of this one.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp302.jpeg

14" LX200R @ f/10, L=7x10'x1, RGB=2x10, STL-11000XM, Paramount ME

Related Designations for ARP302

ARP303

Arp 303 is classed by Arp under Group Character: Double galaxies. He apparently made no notes on this one. Thus, other than there being two galaxies at the same distance, one of which appears a bit distorted I don't see that it is all that unusual. Many exist that to me are far more unusual that aren't in the catalog.

The southern, somewhat distorted galaxy, is IC 563. NED classes it SB(r)ab: pec. It does show a large dark area north of the core and a tidal arm to the west. The northern galaxy is IC 564 classed by NED as SA(s)cd? pec. Its peculiarity seems mostly due to a large radio loop. The pair is located in northwestern Sextans and are about 290 million light-years distant. According to the SDSS, the small blue knot in IC 564 to the southwest, just beyond a redder knot is really another galaxy, SDSS J094619.84+030406.6. They give no redshift data. I doubt it could be seen through the disk of IC 564 so is most likely a foreground object or really what it appears, a star cloud in IC 564. I vote for the latter as there's yet another such "galaxy" in IC 564 per the SDSS. It is a more yellow star cloud directly east of the core that is very small and nearly star-like except for its elongation. Usually these are noted as PofG by the SDSS indicating they are part of the galaxy or NED puts in a note to this effect. Neither happened here but I still am going to vote for them being part of the galaxy, maybe pieces digested from IC 563 when they were closer.

There are two other galaxies in the image that are at the same distance as Arp 303. They are close together to the northwest. The further, bigger and brighter one is IC 561. It is unclassed by NED but looks like a typical disk galaxy except for the two "holes" to the southeast and southwest. The other is, of course, the smaller spiral like galaxy to its southeast. It is SDSS J094602.21+030803.5 and is also not classed by NED. Again the CGCG catalog considers these a pair and records them as CGCG 035-049. Both were discovered by Stephane Javelle on March 21, 1893.

The large, low surface brightness galaxy toward the southwest corner of the image is UGC 5224. At only 100 million light-years it isn't related to Arp 303 but makes a nice addition to the image. It is also cataloged as CGCG 035-048 which considers it a triple galaxy with the blue and red galaxies toward its southeastern end. I find no redshift data but suspect this is just a chance alignment and they really aren't a physical triplet. To the northeast of the triplet as a nice oval galaxy with a large orange core surrounded by a slate blue disk. This is SDSS J094600.84+030141.1. Again I have no redshift data on it. Beside it to the east is the smaller blue galaxy, SDSS J094602.46+030140.3, at 940 million light-years. Why there's data on the fainter one only I don't know. Though it is unusual to see a blue galaxy at this distance.

At the top of the image almost directly above Arp 303 is a very red small galaxy. It is SDSS J094618.88+031417.9 at 1.52 billion light-years. To its east is what appears to be a group of very distant galaxies. While I find each listed in the SDSS none carry any distance data nor do I see a galaxy cluster listed for the area. To the southeast of SDSS J094618.88+031417.9 is SDSS J094618.88+031417.9. It is listed as being 930 million light-years distant. Go directly east from this galaxy some distance and you come to two equally bright blue stars of 15th magnitude. Continue east to the first much fainter orange star. Go southeast to another slightly fainter orange star. Continuing an equal distance brings you to a blue star of about 20th magnitude. This is the most distant object in the image that I'm aware of. It is the quasar SDSS J094649.38+031152.7 with a redshift of z=2.059650. This would put it about 10.5 billion light-years distant. The light was leaving it about the time our galaxy was born and 6 billion years before our sun was created.

Well left of center and a bit south are two 20th magnitude elliptical galaxies that seem in the core of a bunch of much smaller and fainter galaxies. Large galaxies often anchor galaxy clusters. Is that what's happening here? I see no cluster listed. They are SDSS J094702.91+030023.8 and SDSS J094704.71+030024.0. Redshift puts them about 3.6 billion light-years away. None of the smaller, fainter galaxies in the area have redshift data that I could find.

Arp's image:
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp303.jpeg

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

Related Designations for ARP303

ARP304

Arp 304 consists of two galaxies NGC 1241 and NGC 1242, right to left and a double star to the southeast, NGC 1243. The two galaxies were first seen by William Herschel. John Herschel, unable to see 1242 recorded the double star. Dreyer saw all three but recorded the double star as a nebula. It seems odd that even with a 72" scope (speculum mirror I assume) he couldn't recognize 2 14th magnitude stars 12" apart. The NGC is full of such mistakes, some single stars. They are the two stars southeast of NGC 1242. William Herschel found NGC 1242 on January 10, 1785 and NGC 1243 on December 15, 1786. Neither are in a Herschel 400 observing program.

The pair is about 175 to 178 million light years distant in the constellation of Eridanus. Arp put them in his catalog under double galaxies with filaments. I suppose that is the northward arm of NGC 1241. While red shift puts them at about the same distance there's some question about whether they are interacting or not. One note at NED says no, another yes and another wanted more data. NED classes NGC 1241 as SB(rs)b Sy2, NGC 1242 as SB(rs)c:. NGC 1241 does have that odd arm and NGC 1242 seems odd with that very blue northern arm and one heavy arm. So I vote for the interaction being possible. Still, there are no real plumes which is likely why others say no interaction.

The field is out of the Sloan Survey coverage. Only one other galaxy in my field has a known redshift. To find it look well east (left) and a bit south (down) of Arp 304. It is the largest red round galaxy. Further east is a close rather bright double star with a blue galaxy above it. The red one is 2MASX J03121399-0858394 at 1.3 billion light years. The blue one is APMUKS(BJ) B030959.78-090917.2. Other than it being magnitude 18.15 there's no data on it or any other galaxy in the image.

But there is one asteroid 2005 LZ45 at magnitude 19.8 shows up as a short streak angling slightly upward west of the bottom end of NGC 1241. It is at the edge of the 150% crop image above a slightly orange star that's the first up from the bottom right corner of the cropped image.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp304.jpeg

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

Related Designations for ARP304

ARP305

ARP 305 is a pair of galaxies. That's how Arp classified them as well, "Group Character: Double Galaxies. This is the same classification as Arp 303 though this pair is far more interesting. The northern galaxy is NGC 4016. It looks to me as if it has two sets of spiral arms. One set narrow and looping back to the core like a pretzel while the other pair are broad and set at nearly a right angle to the first pair. Both are obviously due to tidal effects of a close encounter, probably with NGC 4017. But explaining their vast difference would seem to me to be a major headache. Could it be two merged or superimposed galaxies? If so, rotational rates would likely be different but since we see it so face on, likely not enough different to be measurable. NGC 4016 is classed by NED as SBdm:. Train-wreck is likely a better classification. One note at NED says of it: "Distorted, patchy, hints of spiral structure in the outskirts". Odd but I thought those arms were rather obvious. Why it isn't classed as peculiar as well I can't fathom. NGC project though does class it SBc-Irr which makes more sense to me.

NGC 4017, while at first appearing more "normal" shows strong signs of interaction with NGC 4016, not the least of which is the faint connection that seems to run from its northern arm up to NGC 4016. Most obvious is the debris almost dead center between them. It seems a bit "windswept" (to use an Arp term) with wisps of stars appearing to have been "blown" northwestward. Arp commented on this filament when he said: "Segment breaking from arm of small galaxy, weak filaments reach to north galaxy, which has figure 8 loops." The detached piece plus the faint piece half way between almost make it look like the northern arm of NGC 4017 is shooting star blobs at its companion. Note too that there's a lot of debris off the southern arm as well that heads nearly due east. I've attached a 150% enlargement of my image that shows this a bit better than the main image. I suppose any residents living on stars orbiting these detached pieces would resent being called debris. NGC 4016 was discovered by R. J. Mitchell on March 30, 1854 while NGC 4017 was seen by William Herschel on April 11, 1785. It isn't in either H400 observing program.

The pair are located about 170 million light-years from us. NGC 4016 is located about 2/3rds of a degree south of the southern border of Ursa Major only a few seconds of arc into Coma Berenices from Leo. About 10 minutes of arc north of my image is the center of the NGC 4008 group. This group is listed in NED to be about 170 million light-years distant. It is likely Arp 305 is part of the group. Not far from its center is NGC 4004 which is also highly distorted and on my list for next spring. It too is 170 million light-years away and may have tangled with Arp 305.

The galaxy northwest of NGC 4016 is MAPS-NGP O_320_0562408. Its redshift indicates a distance of only 40 million light-years. If so, it is a dwarf irregular galaxy.

Well below NGC 4016 and southwest of NGC 4017 is a small lenticular like, very red galaxy. It is SDSS J115824.86+272340.4 at just under 2 billion light-years. West of it is a blue star, angle up a bit from it toward the very bright blue star, about one third of the way you come to a smaller reddish galaxy, it too is 2 billion light-years away. It is not an IR galaxy like the previous one was and not as red. It is SDSS J115808.00+272428.4.

Southeast of NGC 4017 are two short dashes with a gap between them. This is the asteroid (84842) 2003 AS17 at magnitude 19.1. I took color data between two 20 minute luminosity imaging runs. That created the gap as there's nothing for the color data to color in the gap. Below the western end of the western trail is a very red spherical galaxy. It is SDSS J115903.15+272321.9 and is also just under 2 billion light-years from us. There are quite a few other galaxies in the lower part of the frame that are at this 2 billion light year distance. 2 minutes of arc below the south edge of the image almost on its centerline is the galaxy cluster MaxBCG J179.60472+27.27528 with 22 members per NED. Its distance is listed as, you guessed it, just under 2 billion light-years. With no size given for it, I can't tell if the 2 billion light-years distant galaxies in my image are part of the group or not. It seems likely, however.

The fuzzy galaxy in the lower right corner is MAPS-NGP O_320_0562408.

SDSS image
http://astronomerica.awardspace.com/SDSS-30/NGC4016.php
http://astronomerica.awardspace.com/SDSS-30/NGC4017.php

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp305.jpeg

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

Related Designations for ARP305

ARP306

ARP 306 is classed by Arp under his double galaxy class. It is located in Pisces. Arp's comment: "Diffuse, hooked countertail." NED considers this a double double galaxy much like Epsilon Lyrae is a double double star. Each of the main galaxies is listed by NED as being a merging galaxy pair.

The larger galaxy pair is UGC 1102. The lower part is UGC 1102 NED01 at 76 million light-years while the main part of the galaxy is UGC 1102 NED02 with a redshift distance of 74 million light-years. This is the object he refers to in his comment. The "hooked countertail" comes off its north end. When giving the position of Arp 306 Arp used the coordinates of this pair rather than a position between both pairs.

The smaller and fainter pair to the northeast is UGC 1105 with a redshift distance of 79 million light-years. It doesn't have a redshift for each part only one for the pair. UGC 1105 NED01 is the very blue near starlike object toward the northern end of the galaxies core region. The lower, ill-defined part is UGC 1105 NED02. NED's position for the southern part is about the middle of the object where there is a faint, double, condensation rather than the lower, bigger and brighter condensation (all three appear about equal in the SDSS image, however. The lower one wasn't listed which surprised me. The only redshift value given is for the pair.

Did Arp realize this was two pairs of interacting galaxies? If he did he never mentioned it. Though he had little to say about any of his entries, letting the category speak for itself. What comments he did make added little to understanding the object, being only descriptive in nature.

The only other object in the image with a redshift measurement is the galaxy cluster NSCS J013202+044446 to the northwest of Arp 306. It is listed at NED as having 20 members and a redshift distance of about 4.8 billion light years. No diameter is given so how many of the very faint galaxies in this area are members I can't say.

This image contains more asteroid trails than I've ever captured on one image. The L channel was taken over two nights which helps in the capture of so many. 5 came from the first night under rather poor conditions while the other 11 were seen the second night. Four were in both images. Rather than 16 asteroids I actually captured 12, 4 of them twice. Color data came from the second night. So only "bright" asteroids from that night show a color trail.

Arp's image
http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp306.jpeg

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

Related Designations for ARP306