UGC11680

UGC 11680 is a galaxy pair that better fits Arp's category of Spiral Galaxies with Large High Surface Brightness Companions on Arms than many on his list. The pair is located about 340 million light-years away in southern Equuleus, a rather neglected constellation between Pegasus and the much larger Delphinus. Equuleus means "small horse" or possibly "The Foal". At 72 square degrees, it is the second smallest of the 88 constellations. Last place goes to Crux at 68 square degrees, however, with its very bright stars, it is far better known and easier to find. In any case, Equuleus is the smallest constellation visible from most of the United States except Hawaii. This galaxy may be its most interesting object, at least for me.

A note at NED does a good job of describing this one so I'll save the fingers:
"This may be another example of a disk galaxy where the arms are probably tidally induced by the interaction. The B-band (blue) filtered image shows that the galaxy is dominated by strong knots forming a central ring and delineating the outer tidal arms. The east arm form(s) a bridge to the compact companion. At the beginning of this arm, a set of faint filaments are barely visible. Notice the presence of a strong set of knots almost at the tip of the western arm in this galaxy. The apparent morphological classification could be SAB(rs)bc. However, if we consider a tidal origin of the arms and eliminate them from the classification, we classify this galaxy as a SAB(rs)ab. NED classifies this galaxy as a Sa (Sy2). The total (B-V)_T_^0^ color is representative of S0a, Sa types."

The same paper goes on about the companion:
"This is a compact galaxy with a blue central region as can be seen in the {mu} and color profiles. The PA and {epsilon} profiles show hints of an extended structure or arms, probably related to mass transference from the companion. The a_4_/a profiles support the presence of an external disky component. NED classifies this galaxy as a compact:HII (Sy2), however, our classification is E2 pec. The total (B-V)_T_^0^ color is representative of Sa types."

The full article, including the image they refer to (next to the last image), is at:
http://adsabs.harvard.edu/cgi-bin/bib_query?2003A%26A...406..415F
Click on the PDF version.

An older comment at NED says:
"The "bridge" has no relation to the normal spiral arms which are bound
more tightly."

There are more interesting notes at NED on this pair.

No Sloan Survey data from this field has not been entered into NED so there's little information on the galaxies in this field. Most aren't listed. For instance, the little galaxy besides the western arm is not in NED same as the vast majority in the image. The spiral directly west of UGC 11680 with a bright star to its west is CGCG 400-029. Near the west edge, just a tad north of UGC 11680 is the tilted disk galaxy 2MASX J21063694+0352456. The only other identified galaxy in the field is 2MASX J21075002+0352229. It is nearly starlike east and a bit south of the companion. It is at the bottom of four objects curving up and to the left. Both it and the object above and slightly left appear to be galaxies. I think the third is as well. The fourth and faintest may be a star.

The two galaxies I'd like to know about are anonymous. One is the very blue smudge southwest of UGC 10680. The other appears to be a candidate for the Flat Galaxy Catalog. If so, it isn't in NED. It is in the very lower right corner. Looks almost like an asteroid trail but is the same length on all subs so is a very thin galaxy.

The image was taken 8/9/2010. I doubled the L time but it didn't help much to bring out the faint features.

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

Related Designations for UGC11680

UGC11861

UGC 11861/PGC 67671 is a very low surface brightness galaxy in Cepheus about 60 to 62 million light-years distant. The field is very poorly studied with only this galaxy having any distance data or much else for that matter. The galaxy has had two supernovae in it in the last 21 years. I have marked the location of both as neither appeared in a portion of the galaxy that had sufficient brightness for me to see stars in the area. This indicates the galaxy is heavily obscured. Its rather red color may be due to obscuring dust as well.

What drew me to this galaxy was its very odd arm structure, especially the somewhat blue, apparently detached, arm segment just above its more reasonable spiral structure. As with my images this summer the smoke from fires to my north and out in Colorado, the west coast and British Columbia took a tole on my image. How much blue I needed to add back was more than eXcalibrator could handle. At least its results were no better than my unadjusted image. I adjusted blue and green to give a good mix of star colors. Also, 16 Cephi that put a strong halo into the image is F5 so I adjust until that star (not its glare) was mostly blue-white in color. I was unable to find any color images of this field other than a very deep image of the "Shark Nebula that shows it at low resolution. That image doesn't make it as red as my smoke damaged image would indicate. Still, if I push to that image's color then the general stars become way too blue.

I had to use a lot of data to try and piece this together. All that were of a density that could add something are included so there are 7 weak luminance images, 4 rather strong red images and 4 weak blue images. Only 2 green images were usable but that color is easy to adjust for so that wasn't a problem. This is one that I should put on the reshoot list.

My usual method of eliminating the large circular halo around bright stars with some blue color didn't work thanks to the dust. I just left it in as it didn't bother the galaxy and any attempt to remove it would be more noticeable than simply leaving it in.

The last few smoky images are showing smoke starting to coat my filters. I try and set the filter to H alpha when I shut down the camera as I use it least so if it gets hit by spiders, dust or something else, I can clean it at leisure. I failed and left the luminance filter exposed for several of the worst smoke days. That is causing some spikes, long and short on some stars. Due to the background dust in the image, I was unable to remove them without making the image worse so left them in this and a couple prior images. Several more are yet to be processed so I expect they too will have this issue. I've since taken the camera off and cleaned the filters for images taken in September, assuming the smoke ever leaves.

14" LX200R @ f/10, L=7x10' RB=4x10' G=2x10', STL-11000XM, Paramount ME

Rick

Related Designations for UGC11861

UGC12073

The WBL 682 galaxy group consists of 4 galaxies though one appears to be two galaxies sharing a common envelope. It is located in southern Lacerta about 220 million light-years distance. Three (or four depending on how you count the double galaxy) appear to be interacting. The fourth appears to be an innocent bystander.
The WBL 682 galaxy group consists of 4 galaxies though one appears to be two galaxies sharing a common envelope. It is located in southern Lacerta about 220 million light-years distance. Three (or four depending on how you count the double galaxy) appear to be interacting. The fourth appears to be an innocent bystander.

Adding a streak of color to the image LBN 430, the streak through the right side of the image. Beyond it is the UGC 12064 galaxy group also at about 220 million light-years.

UGC 12073 is a large spiral apparently drawn out even further due to interaction with other members of the group. The full extent of its two drawn-out arms reaches about 156,000 light-years making it a huge spiral. The core of this galaxy appears double. I found no mention of this in the literature (what little there was). I don't really see the bar it is said to have. It could be these are knots at either end of a very foreshortened bar that outshines the core.

Near the center of the group is UGC 12075. It appears it could have made Arp's atlas under spirals with a companion on its arm. It appears to have drawn out the arm much like in the case of M51 and its companion. Oddly I couldn't find the companion in NED's database under any designation.

Further east is CGCG 514-055 which appears to refer to both objects in a common halo. While I found a separate designation for the northern core I found none for the lower one other than the above designation centered on the entire halo rather than the dense core. Neither had any distance information. They may be just interacting with each other and not even related to the other three. One note refers to the pair as possibly being a symbiotic pair. I hadn't realized galaxies were living creatures. The bystander is CGCG 514-056. NED doesn't try to classify it. Looks S0/a to my untrained eye.

UGC 12064 is also known as 3C 449 a strong radio source with twin-jets. An HST image shows a 3" wide dust lane around the very core of the galaxy. I wasn't able to find it in my data. Another note says it is rich in globular star clusters but again I didn't pick any up nor does NED catalog any. http://iopscience.iop.org/article/10.1086/317356 Usually the jets are at right angles to the disk of a disk galaxy but not in this case. It might be due in part to the disk being highly warped. You can read a lot more about it at this PDF. http://arxiv.org/pdf/astro-ph/0510650v3.pdf

Being in the zone of avoidance only the major galaxies of the field have been cataloged, even few have much data so the annotated version is rather skimpy on details.

14" LX200R @ f/10, L=4x10' RGB=2x10', STL-11000XM, Paramount MEz
Adding a streak of color to the image LBN 430, the streak through the right side of the image. Beyond it is the UGC 12064 galaxy group also at about 220 million light-years.

UGC 12073 is a large spiral apparently drawn out even further due to interaction with other members of the group. The full extent of its two drawn-out arms reaches about 156,000 light-years making it a huge spiral. The core of this galaxy appears double. I found no mention of this in the literature (what little there was). I don't really see the bar it is said to have. It could be these are knots at either end of a very foreshortened bar that outshines the core.

Near the center of the group is UGC 12075. It appears it could have made Arp's atlas under spirals with a companion on its arm. It appears to have drawn out the arm much like in the case of M51 and its companion. Oddly I couldn't find the companion in NED's database under any designation.

Further east is CGCG 514-055 which appears to refer to both objects in a common halo. While I found a separate designation for the northern core I found none for the lower one other than the above designation centered on the entire halo rather than the dense core. Neither had any distance information. They may be just interacting with each other and not even related to the other three. One note refers to the pair as possibly being a symbiotic pair. I hadn't realized galaxies were living creatures. The bystander is CGCG 514-056. NED doesn't try to classify it. Looks S0/a to my untrained eye.

UGC 12064 is also known as 3C 449 a strong radio source with twin jets. An HST image shows a 3" wide dust lane around the very core of the galaxy. I wasn't able to find it in my data. Another note says it is rich in globular star clusters but again I didn't pick any up nor does NED catalog any. http://iopscience.iop.org/article/10.1086/317356 Usually the jets are at right angles to the disk of a disk galaxy but not in this case. It might be due in part to the disk being highly warped. You can read a lot more about it at this PDF. http://arxiv.org/pdf/astro-ph/0510650v3.pdf

Being in the zone of avoidance only the major galaxies of the field have been cataloged, even few have much data so the annotated version is rather skimpy on details.

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

Related Designations for UGC12073

UGC12193

The WBL 687 galaxy group is a small group of 3 galaxies in Pegasus just west of the northeastern star of the Great Square, Beta Pegasi. Redshift puts the group about 420 million light-years distant. The group consists of UGC 12191, UGC 12193 and CGCG 474-032. Redshift also shows UGC 12198 to be of about the same redshift. Out of my frame to the north, UGC 12194 is a similar galaxy with a very slightly greater redshift that puts it 430 million light-years distant. These 5 likely constitute the PPS2 007 group. Though it is centered just above NPM1G +27.0631 which has no redshift but appears to be more distant so likely this is just coincidence. Still, I'd like to know more about this galaxy as it appears to have a plume to the southwest yet no interacting companion is to be found. Is it the result of a merger?

UGC 12191 is an SB spiral at 420 million light-years by redshift but about 100 million light-years closer by other measurements. Since the other galaxies all have the same redshift as it has I'm going to go with the redshift distances here though this results in a very large galaxy. It is a nearly face-on Sb spiral that's some 165,000 light-years across if the 420 million light-year distance is correct. Going with the nearer distance makes it a130,000 light-years in diameter, still very large as spiral go.

UGC 12193 is listed at NED as an SB(s)bc spiral and is seen fully face on. It is slightly larger in angular size though looks much larger since it is seen almost fully face on. Its size works out to be 175,000 light-years in diameter. There were no non-redshift distance estimates for it.

The third, much smaller, member is CGCG 474-032. It is a rather normal sized spiral at 65,000 light-years in diameter. It appears to be an old, dying spiral by its mostly red color. It stands in rather stark contrast to the vibrant star formation in the larger spirals evidenced by their strong blue color.

The two UGC galaxies are separated by only 110 seconds of arc. If they are at the same distance that would mean they could be as close as a quarter of a million light-years. I'd expect some tidal distortion though if this is their first time close that might not show as yet. Still, I think it likely there's more separation than this between them. Of course, they might be unrelated though I find this unlikely.

The probable 4th member of the group UGC 12198 is seen rather edge on, still, it is rather large at 110,000 light-years across. It too seems to still have active star formation, unlike CGCG 474-032.

There's not a lot on this field at NED. As such, I broke my usual rule and annotated all galaxies at NED in the field, not just those with redshift distance. I didn't include those that are listed as UvS sources as most are stars and separating the two nearly impossible with more than 400 listed in this image to sort through.

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

Related Designations for UGC12193

UGC12342

UGC 12342 and UGC 12350 are the two main galaxies in the image. UGC 12342 is the seagull-like galaxy and is about 355 million light-years away. It is classed as SB? I can't even tell if it is 1 or 2 galaxies as I see nothing in the literature indicating it is two. In the enlargement, I can see hints that 2 may be involved as indicated by the strong color change. How else to explain the messy state it's in. It was picked up by the 2 micron survey so likely has massive star formation hidden behind dust, another indicator of a collision in progress.

UGC 12350 is only about 82 to 96 million light years away (depending on who you listen to). So it is just sharing the same field of view with UGC 12342. It is classed as Sm.

More interesting is the tiny pair of galaxies east of 12350. They are 2MASX J23053932+1650548 and have a redshift distance of 1.3 billion light years. They appear to be an interacting pair. I can't find anything on them, however.

While there are a handful of other 2MASX galaxies in the image there is little on them.

These galaxies are located in Pegasus just north of Markab the southwest star of the Great Square of Pegasus and at the base of the horse's neck.

I've included an enlargement of UGC 12342 at 0.67" per pixel better showing its very weird detail.

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

Related Designations for UGC12342

UGC12591

UGC 12591 is a near edge-on galaxy in the belly of Pegasus about 300 million light-years distant by redshift. Though non-redshift distances vary greatly they average about 400 million light-years. In this case, I think the redshift measurement is closer to the correct value. It's not much to look at but very interesting scientifically which is what put it on my to-do list.

This galaxy was studied in an attempt to find the missing baryon matter in the universe. This has nothing to do with dark matter nor dark energy. It dates back to the big bang which should have created twice the baryonic matter than we see. One idea was that it was hiding in hot galaxy halos. Two galaxies with such halos, NGC 1961 and UGC 12591 were studied by the XXM-Newton X-ray telescope in an attempt to find this missing matter. It came up empty. The halos contained the expected amount of baryonic matter not the excess hoped for. Then, just recently, some, but probably not all, of the missing matter has been found in streams between galaxies. It was this study of UGC 12591 that put it on my to-do list. That and its very dense, red dust lane.

You can read about the failure to find the missing matter in UGC 12591 here http://iopscience.iop.org/article/10.1088/0004-637X/755/2/107/meta

A short article on where much of it was found is here: https://phys.org/news/2017-10-teams-astronomers-evidence-baryonic.html

While the galaxy has been studied, at least in X-rays, the field hasn't. Only one other galaxy in the field has redshift data. NED had only one other object in the field with redshift data but it is slightly blue shifted and appears to just be a very hot blue star in our galaxy that is emitting a high level of ultraviolet light due to its extreme temperature. I marked it since there was nothing much else to annotate. Nothing else even had a magnitude listed and all only had their position for a name.

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

Related Designations for UGC12591

UGC12812

Mrk 331 is a Luminous InfraRed Galaxy in the Great Square of Pegasus about 240 million light-years distant by redshift, 160 million light-years by Tully Fisher and 250 million light-years according to the HST website. NED classifies it as Sa;LIRG HII; Sy2. But it has all the characteristics of a starburst galaxy yet that isn't mentioned at NED. The HST studied it trying to determine if the starburst activity was due to it being the product of a recent merger but couldn't confirm that was the case. Arguing against this being the result of a merger is that it is rather undisturbed. The original entry by Markarian does say it has a small jet to the north but neither my image nor the HST image shows this "jet". Not having access to Markarian's data I don't know what caused this comment. Assuming it is 250 million light-years distant it is some 80,000 light-years across. A reasonably sized spiral. In my image, it has a red side and a blue side. The HST image shows the red is due to many fine dust lanes that merged into one red blob at my much lower resolution. The relatively dust free side shows blue making for an odd color contrast to this galaxy.

The HST image and more information on this galaxy can be seen at: http://hubblesite.org/image/2313/news_release/2008-16 There you will notice they call it UGC 12812. According to NED, this isn't quite correct. NED shows UGC 12812 as a double galaxy with the near edge on spiral to its west. Mrk 321 is listed at NED as UGC 12812 Notes02 indicating it is one of two galaxies. The one to the west is simply noted as UGC 12812. Darned confusing if you ask me.

UGC 12812 (to use NED's name) is listed as Sc with HII emission. It is also listed as 2MFGC 17903 indicating it made the 2 micron flat galaxy catalog. The HST page refers to it without name saying it has lots of star clouds. They don't give a distance for it. Redshift puts it very slightly closer than Mrk 331. The difference is likely due to relative velocity and they are really about the same distance. If so then the starburst activity in Mrk 331 and the many new star clusters in UGC 12812 may be due to interaction between them in the recent past. Assuming this is the case it is some 70,000 light-years across.

Sandwiched between these two UGC 12812 galaxies is MCG +03-60-033. This very blue galaxy isn't classified by NED. I'd say it's a very distorted spiral. Much like our Magellanic clouds. It too is full of new blue star clouds. This may be a 3-way interaction as its redshift is between that of the two UGC 12812 galaxies. Indeed, the three form a triple known as HIPASS J2351+20. This is a Parks Radio telescope survey object that covers all three galaxies. Its irregular shape makes its size hard to measure but I put it at about 35,000 light-years in size. It has an arm that seems to be reaching out to the edge on UGC 12812.

The only other galaxy with redshift data is the small dense blue galaxy west of the trio of galaxies. It is [WGB2006] 234842+20170_d and lies about 1 billion light-years distant or 4 times further away than the trio. I measure it at about 65,000 light-years in size. Obviously, it has no connection with the others.

Nothing else in the image has redshift data so I didn't prepare an annotated image.

Conditions were rough for this one. Even after several nights of trying only one blue frame was usable. With objects this faint that may have hurt the color balance a bit but it appears reasonably close to the pseudo color HST image. Narrowband filters were used for the HST image and prepared in such a way to make a "sorta" true color image. That makes judging my color accuracy pretty much impossible but I think it not significantly far off the mark. The poor conditions did limit my ability to pick up faint plums but since the HST image was looking for them and not finding any it appears I got lucky and didn't miss any I'd otherwise have picked up.

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

Related Designations for UGC12812

UGC12914

Taffy Galaxies

I've been covering Arp Galaxies but still had many to go when this was written. They are usually very interesting but aren't the only interesting galaxies out there. Arp missed the Taffy Galaxies. No they aren't named after someone named Taffy. They are named after the candy! They come in pairs as they are interacting galaxies. Only two pair are known. Both discovered by the same team of radio astronomers. The first in 1990 and the second in 2002. They get the name from their appearance in radio "light" rather than visual light. It seems they are the result of a direct collision of two galaxies, not just a side swipe as most are. When galaxies collide the stars in them don't collide. The space between stars, even in the cores of galaxies is so great they pass right by each other and if the speed is high enough gravity has little time to act and their orbits around their galaxies are hardly disturbed. Thus it is possible for two high speed galaxies to collide and not much involving the stars happens. No tidal arms for instance which require time to develop. But things are different for gas clouds in the galaxies. They can collide. If they have strong magnetic fields (magnetism is trillions of times stronger than gravity -- for instance a small magnet can counter the gravity of the entire earth pulling on a pin, the earth's gravity easily losing this tug of war) they can get entangled in the collision. Instead of a tidal arm of stars you get a magnetic arm of gas between the two galaxies. These are twisted by the twisted magnetic fields much as a candy maker twists taffy, hence the name. So far only two pairs of such galaxies are known. I've now managed to image both. So while I have years to go to get all Arp galaxies I've now captured all taffy galaxies.

This is the first pair to be discovered. The first pair discovered is UGC 12915 and UGC 12914 east to west (left to right). Here there is some visual evidence of the molecular connection between the two we can see visually. Note the very faint reddish band between them. This is very similar to the few Extended Red Emission nebula I've featured. Dust pulled from these clouds by the taffy connection is glowing from the ultraviolet light of hot stars in the two galaxies. This isn't ionized hydrogen as the ultraviolet light isn't sufficient for this but it can light up the dust pulled out along with the gas from the collision. This pair is about 185 million light years distant. UGC 12915 (left) is a Sc LINER galaxy according to NED while they show UGC 12914 as (R)S(r)cd: pec LINER. Both show some distortion from their collision. I measure the size of UGC 12915 at 75,000 light-years and UGC 12914 at 125,000.

The image was taken under rather bright skies due to some ground fog and strong air glow. This limited how deep I could go. I see hints of plumes from both of these in the raw FITS data but it was just too noisy to survive processing. The sizes could be larger if these plumes are real.

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

Related Designations for UGC12914

UGC4332

The Cancer Galaxy Cluster is far larger than my field of view. It is about 220 million light-years distant and in the constellation of Cancer of course. I chose to center on NGC 2563 a large S0 galaxy. The annotated image shows the redshift distances to major galaxies in the cluster which are obviously altered by the relative motion of the about the cluster's center of gravity. The cluster contains some 100 galaxies according to NED but no angular size is given. Suffice to say it is quite a bit larger than my image.

While I centered on NGC 2563 my main target was UGC 4332 to its right. NED classes it as SAdm and puts its distance in line with it being a Cancer Cluster member. The m indicating something is odd about this one. It sure is. UGC 4332 is one strange galaxy. At one time it was considered a polar ring galaxy but most now say that's not a sure thing today.
http://www.springerlink.com/content/f66u183818771544/

The dust lane is very strange cutting across the edge of one spiral arm. My first impression was this is two near edge on galaxies one superimposed over the other. The closer having an intense dust lane. The upper right part being the closer galaxy with a low surface brightness but dense dust lane while the lower and main arms belong to the more distant one. I found no one suggesting this, however.

The Sloan image seems to show a second, much fainter, dust lane above and parallel to the first. The densest part of it is seen in my image as well. Could this be the dust lane going around to the other side of the faint but dusty galaxy? OK, I'm hung up on this being two galaxies rather than one. I did find one amateur (name unknown) who suggests it might be a spiral superimposed over an elliptical. That doesn't explain the tilted dust lane in relation to the plane of the disk. Is it possibly three galaxies, an elliptical and low dust edge on about to merge but still rather undistorted and a foreground super dusty but faint galaxy? In any case, it sure looks strange. A dust band not in the plane of the disk is difficult to explain. Yet I find few are trying.

There was a very blue, small, distorted galaxy northeast of NGC 2563. I was disappointed to find it wasn't in NED though immediately west of it was a far fainter starlike galaxy that was cataloged. Again a very blue galaxy is somehow overlooked. This is a common event I'm finding. Wish I knew why. It is noted with a question mark and line to the blue galaxy. If I had put the label immediately right as I normally do it would have covered the starlike galaxy that was cataloged.

GMBCG J124.81813+21.03969 is a galaxy cluster at 3.6 billion light-years toward the right center of my image. It is labeled G/GC 3.6. The probable anchor galaxy has the same coordinates as the cluster. It is faint at 21st magnitude as my image doesn't go as deep as normal due to a thick haze that night. The galaxy is SDSS J081916.35+210222.8. The cluster is small with only 9 members.

The lone asteroid is 5009 Sethos. It's naming citation reads:
"Named after the Egyptian pharaoh Sethos I (reigned 1304-1290 B.C.) of the 19th dynasty. His father was Ramses I, who reigned for only two years. Sethos I built the Great Hall of Columns of the Amun temple in Karnak and the Osiris temple at Abydos. Sethos I was the father of Ramses II."

The annotated image shows catalog names for all objects with redshift data and are under 300 million light years distant. Those over this I didn't consider true cluster members and indicated them only by their distance. I was rather surprised to find no quasars in the field though one is just outside the field to the east.

NGC 2560 was discovered by Heinrich d'Arrest on March 17, 1862. NGC 2562 and 2563 were discovered by William Herschel on March 23, 1887. Neither are in either H400 observing program.

This image was taken automatically right after the NGC 974 image. That one lost both blue frames due to clouds and haze. This one had a similar problem with the red frames. Since red light doesn't scatter as bad as blue it was sort of usable. Still, faint red was totally lost with the red limiting magnitude a good 1.5 magnitudes brighter than that of blue and green. Thus the dust lane of UGC 4332 is black for the most part rather than red as the Sloan image indicates it should be. That also means the outer, faint parts of the galaxies also likely lack red they should have. Another for the retake list.

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

Rick

Related Designations for UGC4332

USRSA MINOR DWARF

The Ursa Minor Dwarf galaxy is a member of the local group of galaxies. It is about 230,000 to 240,000 light-years distant depending on which source you look at. It is composed of old stars and has little to no dust or gas so won't be forming many new stars. In fact, it appears that star formation was confined to a single event some 12 to 14 billion years ago. This likely is when our galaxy itself was formed. So its stars are all smaller and fainter than our sun. No wonder it is so faint. This is based on the paper: http://iopscience.iop.org/1538-3881/118/1/366/pdf/1538-3881_118_1_366.pdf . It was discovered by A. G. Wilson (Albert George) on the POSS 1 survey images in 1954. It is usually classed as dE4.

My field is too small as it extends out the upper part of the image to the left and the lower part to the right so is very elongated. Seems too elongated for E4 status. My low transparency prevented me from picking up much of the faint glow from its stars. Though look to the lower left and upper right to see its edges as the background does get dimmer there as you move away from the galaxy's boundaries. I need to redo this one on a far better night though those aren't happening as yet. It might be easier to see on the half size image where its resolved stars are closer together better defining its location. Also, the reduced resolution allowed me to push the data further so some of the faint glow near the center of the galaxy is more visible. This one needs to be redone on a night of better transparency and more luminance subs.

While the area has been covered to some extent by the Sloan Survey Data Release 9 none of the over 3000 galaxies in it have redshift data. Though two quasars and the galaxy IC 1110 do have redshift data as well as one galaxy cluster though that is photographic rather than spectroscopic. I've marked them on the annotated image. There are three candidate galaxy clusters listed at NED but seeing nothing at those positions in my image I didn't include them in the annotated image. No size nor membership count was available for these possible clusters and their position was very general. I tend to omit what I can't find in my image so these were not included making for a very sparse annotated image. IC 1110 was discovered by Lewis Swift on August 2, 1888.

14" LX200R @ f/10, L=4x10' RG=2x10' B=3x10 (all blue and one R and G hurt by clouds), STL-11000XM, Paramount ME

Related Designations for USRSA MINOR DWARF