PGC058049

I Zw 148/PGC 58049 is one messed up piece of galaxy parts in Hercules about 375 million light-years distant. It has three listings in NED. The one for I Zw 148 points to the northern blob of the north south piece yet gives its size as 0.4x0.3 minutes which is the size of the entire object. It then says it is an E2 galaxy. If so it is the first very blue elliptical I've ever seen. This is only the start of the confusion in this image. It is a rather small mess being 36,000 light years north to south and 40,000 light-years east to west. I am measuring it as 22"x20" in size so slightly different than NED's 24"x18".

NED lists the left end of the east-west bar as ASK 254551.0 giving a size that matches the entire length and width of the bar. Fortunately, they make no classification attempt. NED then lists the vertical bar as ASK 255273.0 again without classification but with dimensions that match the near vertical bar and coordinates that point to the bigger blob below the one they use for the coordinates of I Zw 148. All three have similar redshifts that are about 0.375 billion light-years but due to rounding one is 0.38 and the other two 0.37. I had hoped for better seeing. As it was getting to where the moon was setting seeing was great but by the time the moon set seeing had deteriorated. There's a lot more to this object than I captured. So I have included a 0.19" per pixel image from Sloan where all the various pieces can be seen. Zwicky considered this a blue post-eruptive galaxy with compact knots. To me it appears to be two colliding galaxies. The east-west bar one and the north-south mess the other. There may be the start of a polar ring about the vertical segment. This is one I wish the HST would visit. So far it isn't in the public HST database. I Zw 148 is considered a member of the Abell 2199 galaxy cluster which is centered about NGC 6166 1.5 degrees to the southeast. The cluster has a listed diameter of 3 degrees and a distance of 410 million light-years, virtually the same as many galaxies in this field including I Zw 148.

While this mess is confusing enough for one image there's still more confusion. This time about the galaxy to the northeast. NED identifies it as NGC 6138 but does admit the identification is uncertain. SIMBAD and The Sky 6 Pro agree with NED but make no mention about the uncertainty. Yet this is quite likely wrong! The real 6138 is NGC 6363 one hour further east. You can read about this one hour error which was straightened out by Steve Gottlieb. You can read about it at his site http://www.astronomy-mall.com/Adventures.In.Deep.Space/steve.ngc.htm . It really is an Sb spiral that made the 2 micron flat galaxy catalog as 2MFGC 13166. That's how it is identified in my image. I measure it at 140,000 light-years in size assuming the 440 million light-year distance.

While NGC 6138 was a bust there are true NGC galaxies in this field. NGC 6145 is the Sb or Sc spiral (depends on the source) below I Zw 148. It is a bit under 90,000 light-years across. It was discovered by John Herschel on May 12, 1828. NGC 6147 is a small Sb or S spiral (yet again sources vary) discovered by George Stoney on May 26, 1849. It is only 44,000 light-years across. NGC 6146 is a large E or E2 elliptical (again sources vary, NED adds that it is a Passive Elliptical Galaxy, that is it has little or no star formation) discovered by William Herschel on March 18, 1787. It isn't in either Herschel 400 observing list. It is over 200,000 light-years in size so a whopper of a galaxy. It is also involved in some confusion. Some sources identify it as NGC 6141. The real NGC 6141 is in the southwest corner of my image. It has a bright region surrounded by a faint disk but conditions were so poor the night I took this that I failed to pick up that disk. It was discovered by Guillaume Bigourdan on May 27, 1886. It is classified as S?, S?? or S0 again sources vary. Including what faint part of the disk, I picked up it is 81,000 light-years across. The bright region is only 30,000 light-years in its long dimension. All the NGC galaxies carry a redshift value consistent with that of the Abell 2199 galaxy cluster.

While much of the field is filled with Abell 2199 galaxies it also has the usual assortment of random galaxies and quasars as well as distant galaxy clusters. But no asteroids.

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

Related Designations for PGC058049

PGC058135

This field is located in Hercules. It is on the north-northwest edge of Abell 2199 and the south-southwest edge of Abell 2197 galaxy clusters. Both have a distance estimate of about 410 million light-years. This accounts for the majority of the galaxies in the field being at about this distance.

My original target was the pair of galaxies known as NGC 6150. When I checked the field I saw a several other interesting looking galaxies in the field and decided to record the aim point as being PGC 58135 to pick them all up. In the 10 second image I used to check the frame it appeared very strange to me. Turns out I was fooled by a bright star at the north end and a fainter one at the southern end. Unfortunately, these cover some likely interesting detail. While the galaxy looks to have a ring structure I doubt that it is real. It is a barred spiral in which the north arm suddenly bends left. This is hidden by the bright blue star. Then it runs on a tangent to a similar arm coming from the southern end of the bar. This is hidden behind the orange star. The arm then flares outward ending about where I put the label in the annotated image. The southern arm does the same at the northern end of the galaxy, again hidden behind the bright blue star. It then curves on around parallel to the other arm ending just as it reaches the orange star. So it isn't all that odd, just that the stars hiding what's going on give it that appearance.

Redshift puts it a bit more distant than most of the field, at 460 million light-years though two non-redshift measurements using the fundamental plane method put it at only 360 million light-years. I'm a bit lost as to why this method was used. I'd always thought it was designed for elliptical galaxies rather than spiral galaxies. I'm going with the redshift which makes the galaxy about 110,000 light-years in size. A rather large spiral.

NGC 6150 is usually considered only the larger and brighter galaxy with the fainter sometimes identified as NGC 6150B. Their redshifts differ slightly. I see no sign of interaction between them so suspect they actually aren't related other than being in the same Abell cluster. NGC 6150 was discovered by William Herschel on March 18, 1787. It isn't in either Herschel 400 observing projects. NED and the NGC Project classifies it as E? while Seligman says E5?? NED considers it part of Abell 2199 while the NGC Project says it is in Abell 2197. I'll not take sides here as to me it is just one two-lobed cluster, likely a pair of clusters in the early process of merging. I measure NGC 6150 at about 125,000 light-years across while 6150B is a bit under 90,000 light-years across. It was discovered by William Herschel on March 18, 1787. It isn't in either H400 program.

Below NGC 6150 is a truly strange looking galaxy, MRK 881. NED classifies it as an Irregular galaxy with HII emission, likely due to the two obvious blue star clouds on its northwest side. To me, it looks like a disrupted spiral but I can live with the irregular classification. Though I am bothered by its 90,000 light-year size. Irregular galaxies are normally less than half this size. This is in line with a disrupted spiral.

Southwest of PGC 58135 is a very small galaxy that NED labels a Blue Compact Galaxy. It is rather gray in color in my data. The Sloan data which maps blue to near UV shows it very blue. I suspect most of the blue is from UV which is blocked by my filters. I measure it at 13,000 light-years across its longest dimension. NED, however, sees it larger than I do which results in a 20,000 light-year size. Normally NED's sizes are smaller than mine rather than larger so the difference is a puzzle.

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

Related Designations for PGC058135

PGC058928

PGC58928 is a huge galaxy in Draco about 410 million light years distant. I measure its size at about 180,000 light-years. It is classified by NED as SBb. It has two large outer arms that form a nearly perfect ring making it look a bit like Saturn. Northern skies are poorly surveyed as to galaxies. This field is no exception. While there are many background galaxies in the image I found none with distance information or classification. Thus no annotated version was prepared.

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Related Designations for PGC058928

PGC1381773

SDSSCGB 00089, also known as PGC 1381733, is a pair of interacting galaxies about 1.15 billion light-years distant in the constellation of Equuleus. Equuleus is the smallest constellation in the northern hemisphere. Only Crux in the southern hemisphere is smaller. While SDSSCGB 00089 consists of two galaxies it has 4 subentries for this object. Two knots in the southern ring galaxy have their own designations even though they aren't really separate galaxies. I've noted all 4 on the annotated image.

The northern member has a strong core with a plume to the northeast. High resolution SDSS images of it show the plume has a hole in it so it shows elements of being a ring galaxy, just not as obvious as it is for the southern member. Only this northern member has a redshift listed at NED. I assume the southern ring is at virtually the same distance. NED makes no attempt to classify either of these apparent ring galaxies. In case you were wondering SDSSCG stands for Sloan Digital Sky Survey Compact Galaxy (groups). The B means it is from the B catalog of the 6th data release (DR6).

Rings similar to that seen in the southern member are often modeled by direct impacts by a small, very dense, galaxy that acts something like a bullet blowing the target galaxy into a ring. often the core is driven to the ring. Finding nothing on this pair I don't have any idea if this is a likely reason for the way this pair appears.

I can find no notes of how I learned of this pair. It was saved under the designation for the galaxy to the southeast at 920 million light-years rather than its own designation (PGC 1381773). This might be because the other galaxy is in The Sky but this one isn't, allowing me to aim by object rather than coordinates. I have a tendency to mistype coordinates. You don't want to know how many wrong fields I've managed to take due to such typos. So I use a nearby object when the object of interest isn't in the database.

I've prepared an annotated image for this rather barren field. Nothing much of interest is to be found in it, however.

The image was made over two nights. Neither very good. The color data from the first night was totally unusable. The data from the second night barely so. Neither night's luminance data was very good. Seeing was worse the first night but transparency better. While including it hurt resolution somewhat it was necessary to get enough signal to reduce the noise to acceptable levels. This is another that could benefit from a reshoot but considering how poor the field is I doubt it will happen.

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Related Designations for PGC1381773

PGC60230

PGC 60230/CGCG 277-042 is a neat ring galaxy near the head of Draco about 41 million light-years distant by redshift measurement. It may be part of the SDSS-C4-DR3 3375 galaxy cluster which is anchored by NGC 6370, an elliptical galaxy in the upper right of my image below a nasty A2 blue star. Right beside CGCG 277-042 is a very low surface brightness messed up looking blue galaxy ASK 019673. Since rings of the type found here are sometimes considered caused by galaxy collisions I had hoped to find information on this pair. Unfortunately, I found virtually nothing. In fact, there are only 3 papers listed at SIMBAD on CGCG 277-042 and none on the companion. Of the three two are just a catalog entry and another providing better coordinates. The third is a study of this type of ring galaxies to try and find a way to separate those created by collision from other causes. CGCG 277-042 was one in the study but that's all. No findings on it at all other than it likely fits their expected conditions. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?2010MNRAS.403.1516S&db_key=AST&nosetcookie=1 Both of these could easily have made Arp's Atlas. He had a category for ring galaxies though it contains only 3, none of which have the core in the center. ASK 019673 at first glance looks a lot like Arp 338, the last one in his atlas. Though it is quite likely two superimposed galaxies, one face on and one edge on as both show a golden core which was lost in Arp's black and white image. It is also a red spiral. ASK 019673 looks to be a single galaxy and is very blue. To me ASK 019673 is the type of galaxy he apparently incorrectly thought he had in #338.

After striking out learning more about this neat galaxy I turned my attention on the rest of the field which, with the galaxy cluster, has a lot of interesting galaxies, including an entry in the Flat Galaxy Catalog, FGC 2132, that's likely a member of the cluster. MCG+10-25-021 is a strange disk galaxy well beyond the cluster that I'd like to see more clearly but the star atop it doesn't help any.

There are 10 quasars and quasar candidates (UvES) in the image which is quite a ways above average. There may be an 11th toward the lower right. It is listed as both a galaxy and quasar. It seems more galaxy like to me. The broad line AGN classification for the galaxy may be more reasonable.

The A2 star sent some nasty reflections over much of the upper right quadrant. I removed some of it but some remains. In doing so I likely reduced the size of NGC 6370 somewhat. The same camera and filters on my 6" f/4 don't create this issue so I have to figure the corrector of the SCT is somehow involved.

NGC 6370 was discovered by Lewis Swift on April 19, 1885.

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

Related Designations for PGC60230

PGC65367 AQU DWARF

In keeping with my policy of posting the winners, losers and all in-between here's a loser.

The Aquarius Dwarf is a very difficult target for me due to its low declination and need for lots of exposure time. I wasn't able to get but 8 images of it with seeing around 3" of arc. All other images were during worse seeing. I got the best result using 4 luminance, two blue and one each of green and red to make a pseudo luminance channel and the 4 color image for the color data. I'll try again this year if seeing this low cooperates which isn't all that likely. Loss of data to clouds will be a common theme from now on as weather has been lousy for imaging the past year. I'm sure I'll find lots of data like this with unusable frames due to clouds or seeing going to pot.

There's a debate over its distance as well as to it being a member of the local group. Its redshift is negative making that of no use though this close it wouldn't http://en.wikipedia.org/wiki/File:Aquarius_Dwarf_Hubble_WikiSky.jpghelp either way. The latest measurements using the Tip of the Red Giant Branch stars in the galaxy put it about 3.1 million light years distant. Its distance would put it in the local group. It is classed as IB(s)m. To me, it is a smudge. For a resolved view see the HST image at http://en.wikipedia.org/wiki/File:Aquarius_Dwarf_Hubble_WikiSky.jpg . It is a rather raw image not cleaned of cosmic ray hits. Also, many stars seem to have dark holes in their center or break up into a ring of pixels when seen at the highest resolution. I didn't try to process my own version. Orientation is north at the top same as my image.

I didn't prepare an annotated image as this one is pretty well out of the area of most galactic surveys. Only one other galaxy in the image has any redshift data. It is 2MASX J20475750-1258569, an IR galaxy located in the lower left of the image. It is about 620 million light-years distant by redshift measurements.

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Related Designations for PGC65367 AQU DWARF

PGC65779

II Zw 096/PGC 65779 as a collision of at least two galaxies in Delphinus east of the dolphin's nose. Redshift puts it about 470 to 480 million light-years away. Oddly NED gives the greater value to the pair and the lesser to both individually which makes no sense to me. The II Zw catalog lists four objects under the II Zw 096 designation. The annotated image points to the A, B, C and D objects. Oddly while C and D point to a region of massive star formation (C) and a potent H alpha region (D) there's no designation for the huge arc of stars to the east. Spitzer and the HST have studied this mash-up. I'll save my fingers and point you to their page on it at http://www.spitzer.caltech.edu/images/3432-sig10-023b-Hubble-View-of-Galaxy-Merger-II-Zw-096 .

Using 470 million light-years for the distance the mash-up is about 90,000 light-years east to west and 77,000 light-years north to south. So these aren't massive spirals

Being in the Zone of Avoidance there's little else available on the field. The low surface brightness spiral to the southeast isn't listed in NED in any form, let alone as a galaxy. I marked it with a question mark for this reason. The only other galaxy with redshift data is CGCG 448-019 in the upper right corner. It resides a good 100 million light-years closer to us but shows few details.

This is another case where the weather was going south on me. Since green is least important I put it last. Sure enough, the weather clouded in on the second green but with a subject like this one green is sufficient so I didn't put it on the reshoot list for that reason. Still, it is one that I can actually put the 0.5" resolution of the system to good use on. Such nights are rare but can happen so it is back on the reshoot list if such a night comes along.

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

Related Designations for PGC65779

PGC72600

KUG 2348+270A also known as PGC 72600 is an Arp like galaxy that happens to be on the edge of the galaxy cluster Abell 2666. It is in Pegasus, about 350 million light-years distant. It's in the Great Square not far from Alpheratz (Alpha Andromedae). While I have many Abell clusters on the to-do list this came as a surprise. I raised KUG 2348+270A high to pick up much of the cluster but not so high vignetting reduced my ability to pick up the plumes. Arp put many galaxies with plumes just like this one on his list. He put them under many different categories however not realizing they were all caused by gravitational interaction with some other galaxy. In the case of KUG 2348+270A, the galaxy involved seems to have hit and run. Now there's a whole cluster of them to choose from. None of which seem all that disturbed. I suppose it could be a merger situation though I see no real evidence for this.

KUG 2348+270A has both a large but faint arm on its eastern side that wraps around under the galaxy then explodes in the plume as well as an odd arm pointing north (up) that also seems to have a lot of tidal stars pulled from it creating a puff of stars about it. The arms seem to create a ring that doesn't attach to the core. NED makes no attempt to classify it other than as a LINER spiral galaxy of magnitude 15. I see a hint of a bar running from the north-northwest to the south-southwest. I found no papers discussing either tidal feature. It has likely had an interaction with another member of Abell 2666.

Abell 2666 is described at NED as having a diameter of 50 minutes which puts its edges well beyond my field though it seems to have run out of members to the north at KUG 2348+270A's distance from its core. Its core as defined by NED is nearly the same as the cD galaxy anchoring the cluster, NGC 7768, a huge elliptical galaxy of 13th magnitude. It was discovered by John Herschel on September 6, 1828.

The field is outside the DR7 Sloan Survey area that has been picked up by NED. It is in the DR8 survey area that NED has not yet incorporated in its database. The Sloan image I've included came from this later survey. Without Sloan data, I didn't expect much in the way of redshift data but apparently, the Abell 2666 cluster has been well studied making for a good deal of data on its galaxies. I've identified all that are in my image that NED knows about. I even identified them along with showing their redshift light travel distance in billions of light-years. Some had no redshift data indicated by a question mark after the catalog name. I used the primary designation NED used so the catalogs are quite varied. Many are likely new to you.

KUG = Kiso Ultraviolet Galaxy Catalogue
GIN = Galaxy Index Number
AGC = Arecibo General Catalog
LCSB = Low Central Surface Brightness

Just east of NGC 7768 is a blue star-like object whose position matches that of 2MASX J23510292+2708335. It is listed also as a radio galaxy in the NRAO VLA Sky Survey. I find nothing on its visual or IR listing. By radio, it is listed as being from 5 to 10 seconds in size. Problem is that on my image it appears starlike with a PSF matching that of stars in the area. I see no galaxy. Adding to the problem is that its location has an error bar of 1.25 seconds. Nor does the DR8 survey show anything other than what appears to be a blue star at this position. I can't help but think something is in error here. I put 2 question marks after its designation for this reason.

The image contains three other NGC objects. NGC 7765. an SB(rs)c? galaxy discovered by R. J. Mitchell on October 12, 1855; NGC 7766 a compact galaxy and NGC 7767 an S0/a? galaxy. These last two were discovered by Ralph Copeland on October 9, 1872.

In the lower right corner is the asteroid (19711) 1999 TG219 shining at an estimated 18th magnitude. It is partly overlapping a distant galaxy.

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

Related Designations for PGC72600

PGC72910

I've had PGC 72910 on my Arp-like to-do list for some time. I finally imaged it in November 2010. Sakib Rasool sent me his list which included VV 697. I imaged that one in October 2010 and posted it 11-25-2011. Processing PGC 72910 seemed familiar to me. Yep, turns out the Tower of babble nailed me again. I had it under different names under both lists. I wasn't going to run this but conditions were better so it shows a bit more detail and better color so I'll bore you with a redo. Besides dummy spent an afternoon on this and hates to waste it. Yes, I've been processing so fast of late my brain is numb.

VV 697 is a triple galaxy system (quad?) in the northeast corner of the Great Square of Pegasus. It lies about 750 million light-years beyond the Great Square to be more accurate. The three galaxies, left to right (east to west) are PGC 72909, PGC 72910 and PGC 72911. Yes, this is backward from the normal west to east numbering system for the PGC catalog. A fourth anonymous galaxy is hiding partly behind the middle galaxy PGC 72910. There's little on this field in NED. The area is included in Data Release 8 of the Sloan Digital Sky Survey but the data hasn't as yet been included in NED's database. I imagine the 4th galaxy will be in that data. I hope with redshift data to see if it is related to the other three.

PGC 72911 is the only one that appears to be significantly distorted by interaction with the others. It is classed by NED simply as peculiar and is noted to be a Seyfert 1 galaxy. While interaction isn't needed to create a Seyfert 1 AGN (Active Galaxy Nucleus) it may be the cause in this case. The center galaxy, PGC 72910 is classed simply as a spiral with a note that it is a starburst galaxy with HII emission. So while it looks rather sedate something (interaction possibly) has triggered massive star formation hidden behind dust in its core. NGC 72909 is also classed simply as a spiral with HII emission but no starburst activity nor AGN.

Except for these three galaxies, NED has no redshift data on any other galaxy in the field. All the others it does list are from the 2MASS IR survey. One, 2MFGC 17969, is also in the 2MASS Flat Galaxy Catalog. It is the obvious edge on flat galaxy northeast (upper left) of the VV 697 group. While it doesn't appear very bright in my visible light image it is listed as magnitude 12.2 in the IR K band. Sounds like it is a very dusty galaxy.

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Related Designations for PGC72910

PGC84446

PGC 84446 is a rather obscure small outlying member of the ABELL 2040 galaxy cluster about 620 million light-years distant. It is located in the very southeast corner of Bootes. The galaxies along the bottom edge of the image are in Virgo while those on the eastern edge are in Serpens Caput so this small field of about 0.2 square degrees includes three constellations. LEDA 84446 is about 60,000 light-years across but at its distance only about 20" of arc across. it is classified as S0/a and as a Narrow Emission Line Galaxy (NELG). It is also sometimes called SDSS 1510+07.

So why did I take such an insignificant galaxy? It turns out to be one of a handful of galaxies known to contain voorwerpjes as they are called. I had to try and see if I could pick up these green objects recently imaged by the HST. They are thought to be illuminated gas clouds outside the galaxy that were left by a galaxy digested by the main galaxy. The illumination coming from a quasar that has since died down to where the galaxy is now just NELG class but the light path from the quasar to the cloud then to us is longer so we are seeing the light echo left by this now quiescent black hole. Most of the voorwerpjes are seen around NELGs. Though only a very few NELGs have voorwerpjes.

The green color is more a result of LRGB filters as the true color is somewhat bluer than seen here. This is because the light from the voorwerpjes is red shifted just enough that instead of falling in the overlap of the green and blue filters it falls entirely in the green filter. The HST uses tunable filters for both the oxygen III seen as green and red for H alpha. Since that is out of my passband I didn't even try for it. The included HST image maps the oxygen to green and the hydrogen to red. As I had no way to isolate the hydrogen and my camera sees the green emission far more strongly than the red of H alpha by almost a 2:1 ratio I see even the red portion in the HST image as green. Also since it was the faint green I was interested in I used more time on the green data allowing it to be pulled out of the noise better than the red. I should have paid more attention to the HST image and put some extra time in on the red filter but didn't.

Seeing was better than it has been much of the last year the night I took this but still far below what I used to get a few nights of the year. Still, it helped to bring out the southern green band.

While the galaxy and several others, mostly on the eastern half of my image are members of the Abell 2040 galaxy cluster most, especially those to the lower right are members of the more distant Abell 2028 galaxy cluster that's about 1.03 billion light-years distant. It is centered in the lower right corner. With two overlapping galaxy clusters, this makes for a very cluttered annotated image. Fortunately, there were no asteroids in the field at the time to add to the clutter.

14" LX200R @ f/10, L=4x10' RB=2x10' G=6x10', STL-11000XM, Paramount ME

Related Designations for PGC84446