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NGC 7437 A Low Surface Brightness Ring Galaxy
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...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 Rick |
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Rick,
that is a nice little galaxy. I guess the ring structure shows in the outer regions which usually would be fainter than here. Stefan |
#3
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See the PDF file page 140 for a diagram of the ring. Even then I can't see it. Whole galaxy is very faint with low contrast detail. I had to push contrast beyond what I normally do just to show what detail I could pull out. Definitely not one for your normal imaging location.
Rick |
#4
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Well, I started to download the PDF but the server seems to be slow, it took ages even with my fast DSL line, so I terminated the download...
Stefan Quote:
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