NGC7436

NGC 7436 is a pair of galaxies in Pegasus about 330 million light-years away. It and its two companions form a subgroup of the Abell 2513 galaxy cluster. The cluster is centered about 20 minutes west of this group and thus the center of the group is out of my field of view. Oddly, looking at its position on the POSS plates I see what appears to me to be a distant galaxy cluster not noted in NED. NED lists no size for the cluster but few galaxies are seen within 15 minutes of what is shown for the center of Abell 2513 other than these extremely distant galaxies. Most of the members seem to be in my frame, odd for the position of the group is out of the frame. I've marked all that NED has redshift data in my frame and they appear to all be members of the cluster. I marked a couple others that are likely members with their distances shown with a question mark that had no redshift data.

The four galaxies that make up the three NGC members of the group (7436 is two) are cataloged as the "triple" Holmberg 800. I found nothing indicating whether the two members of 7436 are interacting. NGC 7435 does appear to have plumes which have sharp cut offs to the north and south. NEG 7436B, the brightest of the group, has a huge halo. Does this indicate they are interacting? The huge halo of 7436 could be the result of it chowing down on members of the group rather than any current interaction and the plumes of 7435 may be normal for it or the result of some long ago interaction. I found no papers shedding any light on this. Certainly, virtually all members of the group are very red and thus not likely to have had much recent star formation. Those in the annotated image denoted as being in the SRGb catalog are also all strong IR emitters which could indicate hidden star formation. None, however, are listed as having active cores. Red spirals like 7435 are thought to indicate galaxies that have had little star formation for the last few billion years allowing all its blue and white stars to die out without being replaced. In any case, I see little dust in any of the members other than SRGb 016.030 in the southeast corner of the image. It does appear to be a somewhat normal barred spiral with blue arms. AGC 321228 also shows a bluer color than the other members. It though appears to be an edge on spiral without a dust lane though that may be below my resolution.

NGC 7436B is classed as E by NED and the NGC Project. NGC 7436A as S. The NGC project doesn't mention it. NGC 7435 is classed as SB(s)a by NED and SBa by the NGC project. NGC 7433 isn't classed by NED and as S? by the NGC project. I suppose the ? denotes that it could be S0 rather than a true spiral. MCG +04-54-007 is classed by NED as Compact; KUG 2255+258 as spiral and UGC 12274 simply as S. No others in the image were given a classification.

NGC 7431 is a tiny starlike pair of galaxies discovered by Guillaume Bigourdan on September 30, 1886. NGC 7433 and NGC 7435 were found by R.J. Mitchell on October 12, 1855. NGC 7436 was discovered by William Herschel on December 2, 1784. It isn't in either H400 project.

SRGb is the Southern Rich Group - big area catalog in case you were wondering. While the group is north of the celestial equator it is at -30 degrees Using galactic coordinates. It is indeed a southern group just not by the coordinate system we normally use to point our telescopes.

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

Related Designations for NGC7436

NGC7437

NGC 7437 is a face on, low surface brightness ringed galaxy. Though the ring is not obvious visually it meets the requirements. It is classified as SAB(rs)d by NED and SAB(rs)c: by a paper detailing such ring galaxies. While the paper is rather deep reading and 160 pages long it does have a diagram detailing the ring structure on Page 141. http://www.aanda.org/articles/aa/pdf/2014/02/aa21633-13.pdf Not all sites even recognize the bar let alone the ring with the NGC project saying it is Sc and Seligman saying Scd?

Other than this paper I found little on this rather faint galaxy. It was discovered by Lewis Swift on October 31, 1885 and is located in Pegasus just southwest (1.8 degrees) of Markab that marks the southwest corner of the great square and start of the horse's neck. Visually it is quite faint in a 17" scope so not an easy target. It was fainter than I expected needing at least three or four times the exposure time I gave it.

There are a lot of galaxies in my annotated image at about 1.2 billion light-years. While there are several galaxy clusters in my image, including one at about that distance it has no size while these galaxies at the 1.2 billion light-year distance are seen across my image it appears there are more at that distance than the cluster can account for with a count of just 21 with much of the cluster obviously below my frame. A couple other clusters are at about 2 billion light-years but I found few individual galaxies at this distance that at about 1.2 billion light-years.

In the upper right quadrant is the spiral galaxy ASK 143213.0 at 2.05 billion light-years. It is so large I can resolve spiral arms in it at that distance. I measure its diameter at 196,000 light-years. That is one huge spiral.

Near the left edge and above center is a galaxy I've labeled as AGN at 3.89 billion light-years. NED actually lists it as a quasar but it is obviously elongated southeast to northwest and therefore not a point source as a quasar usually is.

This marks my move into December images. Though it wasn't my first December image attempt, the first night's data shows severe issues with clouds making processing them nearly impossible. Even if I did I'd have such poor results I'd have to retake them next year anyway. So I doubt I'll try and process that first night's work.

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

Related Designations for NGC7437

NGC7448

Arp 013/NGC 7448 is in Arp's class of galaxies with detached segments. Since all of its spiral structure is composed of many detached pieces of arm structure I'm not sure which pieces or all of them he is referring too. Or is he referring to the large star clusters in the northwestern part of the galaxy that are about as bright as the core? His only comment is that this is a high surface brightness galaxy so that is of no help.

The galaxy is about 84 million light-years distant by redshift and is located in Pegasus just outside the southwest corner of the Great Square. It anchors what is known as the NGC 7448 group. I originally took this galaxy in late 2008 with it centered in the field. This missed all other members of the group. Conditions weren't all that good, especially for blue data. Also my processing back then wasn't all that great either, for color especially. This is a retake of it with Arp 13 moved to the very western edge of the field so I could pick up 4 more interesting members of the group on the eastern edge of my image. They are UGC 12313, NGC 7463, 4 and 5. All show signs of interaction, likely with each other. I've noted their redshift distance and NED classification on the annotated image. While the redshift distances vary between 70 and 91 million light-years they are all likely about the same actual distance from us.

UGC 12313 is a very low surface brightness galaxy that looks somewhat like a spiral with a core region but is classed as irregular which usually has no recognizable core. It has what appear to be plumes at both ends though the one to the northwest is most obvious. The trio of NGC 7463-5 is very interesting with all sorts of plumes. NGC 7465 appears the most interesting appearing nearly face on to us with two outer partial rings of stars whose centers don't match the location of the barred galaxy's core. This is a very unusual structure yet I found little on it in the literature. NGC 7463 is a more edge-on spiral with arms that appear to have been drawn outward by tidal interactions with others in the group. Caught in the middle (apparently) is NGC 7464. A highly distorted elliptical galaxy that is surprisingly blue for an elliptical. In fact, it is bluer than NGC 7463 which is about the normal blue for an Sb galaxy. I'd expect elliptical galaxies to be rather red as normally star formation is usually hidden from our view being isolated to the core region. That doesn't appear the case here.

NGC 7463 and 7465 were discovered by William Herschel on October 16, 1784. Neither are in either of the Herschel 400 observing programs. NGC 7464 was discovered by Heinrich d'Arrest on August 27, 1864.

NED has no other information on the field but for one quasar below this group at nearly 10 million light-years. I see a lot of interesting background galaxies but I can't find much on any of them other than the few NED includes are 2MASS galaxies and thus very bright in far IR radiation.

Arp's image of Arp 13: http://ned.ipac.caltech.edu/level5/Arp/Figures/big_arp13.jpeg

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

Related Designations for NGC7448

NGC7457

NGC 7457 is a galaxy in Pegasus about 9 degrees north-northeast of the northwest star (Beta Pegasi) of the Great Square. My reason for taking it was it was an entry in the second Herschel 400 program. It was bright enough to get through the smoke so I took it through the dust. It is classified as SA(rs)0-? by NED. Seligman classifies it as E/SA0(rs)?. I don't see the ring but when I accidentally loaded the fits into PhotoShop in 8-bit mode one showed up but was dark, not bright. The POSS 11 blue image shows the same dark ring but I was unable to see it in my blue data no matter what I did. Also, it doesn't show in their POSS 1 blue image. Nor do I see this dark ring in the SDSS image no matter which color I used. Did the POSS image use 8-bit scanning or at some step in digitizing the POSS II plate?

The field is not well studied so I wasn't going to even do an annotated image then I found I'd picked up three globular clusters in the galaxy. I needed the disk's light to help bring them bright enough to see as they are nearly 21st magnitude. Nothing else in the image gets that faint. Others outside the disk couldn't be seen in the original FITS stack. You may need to blow up the image several times to see them. They were found in a Hubble image. My attempt to pull them out of the HST data failed so even the HST had trouble seeing them so I don't feel bad about it. https://arxiv.org/abs/0804.4472

Another feature of this galaxy is how strongly stars are compressed towards its core. Yet the HST can't see the very core as it is packed so tightly with stars. It may not even have a massive black hole or if it does it can't be any larger than ours. The stars are packed only a small fraction of a light-year apart, some 30,000 times as dense as the area around our sun. The HST studied it because it was "normal" in every way. They found out that wasn't the case after all.
HST link http://hubblesite.org/news_release/news/1990-08
More at StarDate: http://blackholes.stardate.org/objects/factsheet-NGC-7457.html

Also, the spindle galaxy, UGC 12311, to the northeast turned out interesting as it harbors many small star clouds in its ansae. They look like small faint stars in our galaxy but they are listed in a couple places as star clusters in it. While at a somewhat similar redshift distance I found nothing indicating the two are related. The non-redshift distance to NGC 7457 is likely more correct. Several sources indicate a similar distance though none agree, all are in the 40 million light-year distance range. I found no such estimates for UGC 12311. Its redshift is likely not all that accurate of a distance measurement but if related to NGC 7457 I'd expect closer redshift agreement as they'd be still moving together if related.



http://www.mantrapskies.com/image-archive/NGC/NGC7457/NGC7457L4X10RGB2X10.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7457/NGC7457L4X10RGB2X10CROP125.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7457/NGC7457L4X10RGB2X10ID.JPG


Rick

Related Designations for NGC7457

NGC7479todo

NGC 7479 is a barred spiral about 100 million light-years away. The bar, as many do, is feeding dust and gas to the core. This is giving the black hole at the center something to "eat". Thus this is a Seyfert galaxy. Massive star formation is going on in the arms and to some extent at the very core. The core stars are explained by the constant inflow of material via the bar. That though doesn't explain massive star formation in the disk and arms. A collision would be one reason but other than the distorted, non-symmetrical arms there's little obvious evidence of one. Certainly no obvious candidate in the area. Or is there? Some are now saying this is all the result of a "minor merger" with a small galaxy. A couple papers say they can identify the remains of the merging galaxy. If so it happened some 300 million years ago. Too bad early life on earth didn't have an observatory to verify this. I've attached a cropped version with the suspect marked between two black lines. Unfortunately, my poor winter seeing greatly hurt this galaxy as well, as did my having to image it far to the west where my seeing is always worse, apparently due to a warm area of the lake where springs are located. Its the only reason I can think of for winter seeing to be POOR in that part of the sky. Those of you that like to wade through deep articles can read about this galaxy and the possible merger at: http://www.iop.org/EJ/article/0004-637X/538/1/141/51181.html
Those not into wading through deep "stuff" can jump to the conclusion in the last paragraph and skip the math.

14" LX200R @ f/10, L=8x10' RGB=3x10'x3, STL-11000XM, Paramount ME

Related Designations for NGC7479todo

NGC7490

NGC 7490 is a nice face on spiral in northern Pegasus about 270 million light-years distant by redshift. It has a fairly bright core but faint thin arms. My processing has greatly equalized this brightness difference in order to fit its wide dynamic range into that of a computer monitor. Still, the faintest arms are barely visible, especially the one going through the blue star north of the core. NED classifies it as Sbc, The NGC Project says Sb while Seligman says Sbc?. The spiral structure while obvious far from the core is very indistinct in toward the core making it appear the arms come from a region well outside the core. The northern faint arm that goes to the blue star to the north stops there and a new arm segment begins below the star. From my experience such an arm segment coming from nothing this far from a core is unique. Has some interaction caused this? The second blue arm out from the core on the right has a sudden odd quivering region that average to a straight line then resumes its expected curve as it passes a blue-white foreground star. As you've probably noticed I like galaxies that first appear "normal" but on closer inspection have an odd quirk or two. The wide faint arms make this galaxy quite large. I measure its extreme size on the FITS luminance stack at 210,000 light-years making this an unusually large spiral. It was found by Édouard Stephan on October 11, 1879.

The galaxy is in a pretty lonely region with nothing much in the entire field. It is little studied so even obvious background galaxies are anonymous. I've pointed out one in the bottom of the cropped annotated image with a question mark as no catalog I found including NED, SIMBAD and several programs such as The Sky 6 Pro list it at all. It shows o the POSS plates of the area so is real. With nothing to annotate I wasn't going to prepare one then noticed an asteroid in the image. It is moving nearly north or south. When I checked it at the Minor Planet Checker's site it returned the id of 449911 but without any position, magnitude direction or rate of motion nothing beyond its number. Since I'd asked for any in the image that could apply to anything within 20 minutes of the center of my image and without a magnitude it could be too faint to show. It always returns the positions, magnitudes, motion, etc. so I can then identify all in the image but with no position, no magnitude, no nothing I was lost. I put the number into the ephemeris checker and that showed it was at the position I've marked and gave me the information the checker for some reason failed to deliver. Even a few days later the checker comes up with only the number and nothing else. So if you run into this with some other asteroid go to the ephemeris server to get the data. I've never needed to do this with any other asteroid.

But for this asteroid, I'd not have made an annotated image. It did allow me to point out the one quasar NED lists for the field. Since the majority of the field had nothing to annotate I cropped the annotated image to show just what I had data on.

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

Related Designations for NGC7490

NGC7492

NGC 7492 is a rather sparse globular cluster which has earned it a class 12 (least condensed) rating. It could easily be taken for an open cluster from its visual appearance in images. But its large distance and size show it to be in the galactic halo and the size of a globular cluster. It is 85,700 light-years distant and 82,500 light-years from the galaxy's center so it is well outside the main confines of the galaxy as our galaxy's radius is less more like 50 to 65 thousand light-years depending on whose figures you use.

Its size is something hard to pin down. SEDS puts it at 8.4 minutes across, Seligman says 5, most others say 4 and I get about 6 minutes. Those make it 210, 130, 100 or 150 light-years in diameter respectively.

The odd thing about this globular is the dark band running east to west nearly across the cluster north of its center. Is this devoid of stars or obscuring dust? I found nothing on it either way. Other globulars have some odd gaps but I can't recall any as large or dark as this one.

In 1918 a photographic atlas taken by the Crossley Telescope at the Lick Observatory was published. It says of the cluster: "A very sparse cluster of very faint stars, about 4' in diameter 2 s.n." This indicates the state of the art of imaging at that time. The purpose of the survey was to study small spirals (note at this time it still was undecided if they were whirlpools in our galaxy or possibly external to our galaxy. This survey http://adsabs.harvard.edu/cgi-bin/bib_query?1918PLicO..13....9C was partly an attempt to gather data on the subject. The "2 s.n." at the end of the description means 2 small nebulae were seen in the image. I assume this is the two galaxies seen through the main part of the cluster in my image. They'd not say galaxies as they hadn't been recognized at the time.

The nebula was discovered by William Herschel on September 21, 1876 but is in neither of the Herschel 400 observing programs.

One asteroid came through the image, (79638) 1998 RL78 at magnitude 17.7. The transparency was so bad it appears much dimmer than this. Part of the reason my image isn't very bright is that the globular is just below my normal 15 degrees south declination limit which puts it down in the gunk over the lake. This also hurts seeing which ran 3.1" to 3.5" across the image. Deconvolution and other techniques helped a bit but things are fuzzier and fainter than I'd like. I doubled my ordinary exposure time though I don't think it helped much as I gained photons but the added time just allowed the seeing to extract a seeing price for those photons. I tried the 4 best frames or all 8 and got so similar results it didn't matter which I used. I kept them all as it made for a different asteroid trail as I took blue data between the two luminance runs. Still, for this declination, it is quite acceptable.

There are no redshift measurements for anything in the image so I didn't prepare an annotated version.

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

Related Designations for NGC7492

NGC7497

NGC 7497 is a galaxy about 60 million light years distant set in the Integrated Flux Nebula in Pegasus. The IFN, also known as Galactic Cirrus is dust far out of the plane of our galaxy caused to fluoresce by the ultraviolet light of super hot stars in our galaxy's disk. The galaxy, of course lies some 60 million light years beyond our galaxy and its IFN. It is classed by the NGC project as an Sc galaxy, as an SB(s)c galaxy by de Vaucoulers and as SB(s)d by NED. I'm not seeing it as a barred spiral though it appears I'm out voted.

The bright blue piece of IFN at the far upper left below a very bright star seems bright enough to have made it into a catalog but Simbad has nothing at that position.

There is little on this field. The blue oval smudge of a galaxy southeast of NGC 7497 is NPM1G +17.0731. The blue smudge west southwest of NGC 7497 is MCG +03-59-001/PGC 070552. The bright blue spiral northeast of NGC 7497 is another bright but anonymous galaxy in NED. I keep running into these. Seems no one it catalogs has found it interesting enough to even list as an anonymous galaxy. It's bottom half seems cut off. Look closely and you see a faint arm down in the "cut off" region. Is it obscured by unlit galactic dust? What is going on here?

Only 4 other galaxies in my image are listed in NED. All small and insignificant, at least from my point of view. I see no difference in them than many others not listed. All 4 are from the 2 micron survey so interesting as bright at that wavelength as likely star factories.

This image was taken over two nights. An asteroid from each night shows in the image. The one from the first night, (247103) 2000 SL317 is NE of NGC 7497, two thirds of the way to the anonymous blue spiral and is moving only in R.A. It was just out of the frame to the west the second night. The other asteroid, 2010 JH161, is about 3.6 minutes west (right) of the core of NGC 7497 and moving down at to the right at a 45 degree angle. It's trail starts near a slightly orange star. It was out of frame to the upper left the first night Comparing the two trails you can tell seeing was a bit better the second night. Both are about 19.5 magnitude. Due to the IFN both are very difficult to pick out. Edit: this was taken before I was annotating images with asteroids. Don't spend time looking for these "Where's Waldo?" asteroids.

A blue star at the bottom of the image and a red one at the top hit right on the edge of the chip. When I moved either way to avoid this something put a horrid set of reflections into the image. Only solution was to leave these stars right on the edge where they glared into the image. I could have cloned them out but the blue one was in the IFN and impossible to clone out without distorting the IFN so I decided to leave both in. I did tone them down significantly. Yes they were far worse! I discovered the reflection issue a year after I'd taken it and was just now putting it together. No way to remove it as it hit in the IFN. So I completely redid the image September 3 and 5 of this year. Finally I'm posting a current image.

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

Related Designations for NGC7497

NGC7510

NGC 7510 is a reprocess of an old image. I came across it cleaning the hard drive to get ready for the move to the new computer when I found it and decided to give it another try. This version came out better. NGC 7510 is a very pretty cluster seen visually in most any telescope. It sort of resembles a broadhead arrow point with three razor edges. This is lost in the image however. It is located about 10,000 light years away in the constellation of Cepheus. The whole area is faintly filled with ionized hydrogen, especially to the east. Many nebula I've featured are part of this huge cloud. The bubble nebula is probably the most famous of these. Here we just see the western edge of the huge cloud coming into the eastern part of the image. I moved NGC 7510 high to pick up more of it than I would if left centered.

14" LX200R @ f/10, L=8x10 RGB=1x10', STL-11000XM, Paramount ME

Related Designations for NGC7510

NGC7519

NGC 7519 appears to be a mostly red and dead galaxy in Pegasus below the Great Square. It is about 460 million light-years distant. Its classification varies depending on who you read and even then can vary. NED has it as Sb:, Sb?, and simply as Spiral. Seligman sees it as SBc. So is the arm structure that of a "b" or "c" galaxy? The latter means the arms are more spread out. And does it have a bar or doesn't it. Makes you wonder if they are looking at the same object. It was discovered by Albert Marth on October 5, 1864, by Albert Marth.

My main reason for taking this field was the really strange galaxy Markarian 0526. Check out the Markarian galaxies for strange looking galaxies. Not all are as strange as this one but if you are looking for galaxies that aren't typical it is full of them. This one is classified as Sc peculiar. I assume that the peculiar label is due to the long north going tidal stream. It appears to curve into a bright object but redshift shows that to be coincidence as the bright orange object is a distant galaxy at over 3.6 billion light-years. I assume the tidal stream and odd shape of the disk of MRK 0526 are due to either an interaction with some passing galaxy or due to something it is digesting having eaten it several hundred million years ago. The field is poorly studied. I find nothing near its distance of 280 million light-years in the field. But many in the areas don't have redshift data available. Still, I favor the plume being due to something it ate possibly being the stars pulled from its meal as it fell into the galaxy. While we can look back in time with a telescope we can't make a time-lapse movie except in computer simulations. I'd love to see such a real (not computer generated guesstimate) time-lapse movie of the history of galaxies like this one.

North and a bit east of NGC 7519 are a pair of distant objects, 6.4 and 8.9 billion light-years distant by their redshift. Both are listed as galaxies with AGN cores. But for me to see them this easily (This image is dimmed severely by smoke) I have to wonder if they are really quasars or if the redshift values are in error. They are given to only 3 digits after the decimal point. NED doesn't confirm these to be spectroscopic redshifts. They may be photographic which are less reliable. Usually, spectroscopic redshifts show more significant digits.

As mentioned this field is poorly studied. I've listed all galaxies that redshift values in NED. Several other galaxies without redshift data are identified as well if they had catalog names other than simply their coordinates. Even those with redshift values often had only positional names.

Two asteroids are in the image. The fainter one shows a trail that gets brighter at the western end. This is most likely due to smoke getting less dense. It was coming in clouds that could drift through a field in only a few minutes. While not guiding I do monitor a star with the guide camera for focus. My cloud sensor saw no hint of clouds but the brightness of the monitored star was changing several magnitudes, often only in a minute's time due to various levels of smoke I was imaging through. Because of the smoke, I say NGC 7519 appears to be red and dead. It may be bluer than I show if I haven't fully compensated for the loss of blue and green to the smoke. I couldn't find but a couple color images of this galaxy. One made from DSS red and blue images showed it vivid blue while the SDSS image (not true color but often close) shows it a different red color than I do. But SDSS uses three IR frequencies for red, red is assigned green, green is assigned blue and blue uses two Uv bands making it sometimes hard to interpret. Usually, this makes red and dead galaxies very red due to all the red stars and their IR emission. I need to revisit this without the smoke I suppose. Though it likely won't happen with all the objects still on the to-do list.

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

Rick


http://www.mantrapskies.com/image-archive/NGC/NGC7519/NGC7519L4X10RB2X10G1X10CROP125.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7519/NGC7519L4X10RB2X10G1X10.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7519/NGC7519L4X10RB2X10G1X10ID.JPG

Related Designations for NGC7519