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ASTRO: Arp 138 No plumes but rather neat anyway
Arp 138, NGC 4015, is a pair of galaxies in Coma Berenices about 210
million light-years away. It is right on the border with Leo. In fact the right 25% of my image is in Leo. Arp put this pair in his category Elliptical and elliptical like galaxies: Material emanating from elliptical galaxies. His comment reads: "Absorption leads directly into E galaxy." I presume this refers to the dark cloud off the end of the spiral galaxy's tip. It's hard to tell if it is coming from the spiral or the elliptical. Arp apparently considers it coming from the elliptical or appearing to at least by the category it put it in. Since the elliptical shows no other signs of dust and spirals are often very dusty I'd suspect the spiral as being the more likely source of the dust. The redshifts of the galaxies are virtually the same so no help there. Other than the dust cloud I see no sign the two galaxies are even interacting. If they are it must be just beginning. Apparently they aren't quite as close as they appear to be. NED classes them as S? and E with no further refinement. It appears the spiral is closer to us than the elliptical though its redshift is very slightly larger. Are they on a collision course? No way to know as there's no way to measure their proper motion across the field. They may be moving sideways far faster than their approach velocity. The field has several NGC galaxies in it. I've identified those on the annotated image as well as redshift distances in billions of light-years when known. There are distant galaxy clusters. Their position is marked by the large cD galaxy at the heart of the cluster. They are shown as having 18 or so members but I don't begin to see that many around either cD galaxy. They are marked C/GC followed by their distance in billions of light-years. NGC 4005 is also NGC 4007. Such double names are surprisingly common in the NGC catalog. There are two asteroids in the image. The bright one is (43477) 2001 BX7 at 18.7 magnitude. The fainter at my estimated magnitude of about 19.8 is -- I did it again -- unknown. Found and let another one get away. This was taken March 20, 2010 so a bit late to try and find it again. Minor planet center doesn't have it in their data base is all I know. Arp's image http://nedwww.ipac.caltech.edu/level...ig_arp138.jpeg Sloan image http://astronomerica.awardspace.com/SDSS-30/NGC4015.php 14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
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ASTRO: Arp 138 No plumes but rather neat anyway
Rick,
I would bet on the spiral to be the source of the dust. Anyway, the dust looks neat indeed covering the elliptical. Stefan "Rick Johnson" schrieb im Newsbeitrag ster.com... Arp 138, NGC 4015, is a pair of galaxies in Coma Berenices about 210 million light-years away. It is right on the border with Leo. In fact the right 25% of my image is in Leo. Arp put this pair in his category Elliptical and elliptical like galaxies: Material emanating from elliptical galaxies. His comment reads: "Absorption leads directly into E galaxy." I presume this refers to the dark cloud off the end of the spiral galaxy's tip. It's hard to tell if it is coming from the spiral or the elliptical. Arp apparently considers it coming from the elliptical or appearing to at least by the category it put it in. Since the elliptical shows no other signs of dust and spirals are often very dusty I'd suspect the spiral as being the more likely source of the dust. The redshifts of the galaxies are virtually the same so no help there. Other than the dust cloud I see no sign the two galaxies are even interacting. If they are it must be just beginning. Apparently they aren't quite as close as they appear to be. NED classes them as S? and E with no further refinement. It appears the spiral is closer to us than the elliptical though its redshift is very slightly larger. Are they on a collision course? No way to know as there's no way to measure their proper motion across the field. They may be moving sideways far faster than their approach velocity. The field has several NGC galaxies in it. I've identified those on the annotated image as well as redshift distances in billions of light-years when known. There are distant galaxy clusters. Their position is marked by the large cD galaxy at the heart of the cluster. They are shown as having 18 or so members but I don't begin to see that many around either cD galaxy. They are marked C/GC followed by their distance in billions of light-years. NGC 4005 is also NGC 4007. Such double names are surprisingly common in the NGC catalog. There are two asteroids in the image. The bright one is (43477) 2001 BX7 at 18.7 magnitude. The fainter at my estimated magnitude of about 19.8 is -- I did it again -- unknown. Found and let another one get away. This was taken March 20, 2010 so a bit late to try and find it again. Minor planet center doesn't have it in their data base is all I know. Arp's image http://nedwww.ipac.caltech.edu/level...ig_arp138.jpeg Sloan image http://astronomerica.awardspace.com/SDSS-30/NGC4015.php 14" LX200R @ f/10, L=4x10' RGB=2x10'x3, STL-11000XM, Paramount ME Rick -- Correct domain name is arvig and it is net not com. Prefix is correct. Third character is a zero rather than a capital "Oh". |
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