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ASTRO: Arp 169 Three galaxies, one halo
Arp 169 is a trio of galaxies sharing a common envelope of stars, or at least they appear to. Red shift would put these at about 340 million light years. But studies using the D-sigma method which is often quite accurate when applied to elliptical galaxies puts the distance much closer, say about 280 million light years. The group appears to be part of the ZWCl 2212.0+1326 galaxy cluster, a group of some 138 galaxies about 338 light years. If so then the red shift distance is probably correct. I suspect that the fact these are S0 galaxies and share a common halo has skewed the D-sigma calculation. Still this galaxy cluster has galaxies with red shifts that match the D-sigma value as well. In any case its a ways from us. Arp 169 is Arp's class: Galaxies (not classifiable as S or E) with diffuse counter tails. I see mostly a common envelope of stars, not a counter tail. I think Arp is referring to the somewhat north northeast extension of the halo off the upper right galaxy NGC 7236. The middle galaxy is NGC 7237 with the small galaxy to the southeast being NGC 7237C. Arp's comment; "Faint diffulse plumes coming away from two galaxies. 3C442." This would indicate he sees a plume from NGC 7237 or 7237C as well. I see a hint of one, maybe. The reference to 3C442 is because it seems to be coming from the core of NGC 7237. This could be a sign they are actually interacting causing its black hole to be very well fed at the moment. While one source describes these as elliptical galaxies with no sign of recent star formation most describe all three as blue compact S0 galaxies. From the color of the halos in my image I'd agree with the latter. The halo doesn't have the orange color most always seen with elliptical galaxies. Though there are some exceptions 3 in one spot would seem a bit too much of a coincidence to me anyway. While most galaxy clusters are populted with elliptical galaxies as their most common members this cluster seems to be mostly S0 galaxies. I son't recall seeing so many one on image before. One of the few exceptions is the face on, low surface brightness spiral south and a bit west of Arp 169. It is CGCG 428-057 a 15th magnitude galaxy. I've prepared a simple annotated chart showing distances to galaxies and quasars that are not members of the galaxy cluster that NED had red shift data for. There's a very blue quasar at 8.4 light years right beside a galaxy that is quite likely far closer that the quasar. The most distant galaxy I know of in the image is about half way toward the lower right corner. It is SDSS J221402.08+134424.9 at a magnitude of 21.1. It must be a big one for me to see it at a distance of 4,300,000,000 light-years. Some how that looks much bigger than 4.3 billion light-years. The rather bright asteroid is (88528) 2001 QU177 which is shining at about magnitude 17.4. Arp's 200" image: http://nedwww.ipac.caltech.edu/level...ig_arp169.jpeg 14" LX200R @ f/10, L=4x10', RGB=2x10'x3, STL-11000XM, Paramount ME Besides the full image at 1" per pixel I've attached a cropped version at 0.75" per pixel. 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". |
#2
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ASTRO: Arp 169 Three galaxies, one halo
Rick -
Did you see http://adsabs.harvard.edu/abs/2007ApJ...658L..79W On Mon, 26 Apr 2010 13:16:11 -0500, Rick Johnson wrote: Arp 169 is a trio of galaxies sharing a common envelope of stars, or at least they appear to. Red shift would put these at about 340 million light years. But studies using the D-sigma method which is often quite accurate when applied to elliptical galaxies puts the distance much closer, say about 280 million light years. The group appears to be part of the ZWCl 2212.0+1326 galaxy cluster, a group of some 138 galaxies about 338 light years. If so then the red shift distance is probably correct. I suspect that the fact these are S0 galaxies and share a common halo has skewed the D-sigma calculation. Still this galaxy cluster has galaxies with red shifts that match the D-sigma value as well. In any case its a ways from us. Arp 169 is Arp's class: Galaxies (not classifiable as S or E) with diffuse counter tails. I see mostly a common envelope of stars, not a counter tail. I think Arp is referring to the somewhat north northeast extension of the halo off the upper right galaxy NGC 7236. The middle galaxy is NGC 7237 with the small galaxy to the southeast being NGC 7237C. Arp's comment; "Faint diffulse plumes coming away from two galaxies. 3C442." This would indicate he sees a plume from NGC 7237 or 7237C as well. I see a hint of one, maybe. The reference to 3C442 is because it seems to be coming from the core of NGC 7237. This could be a sign they are actually interacting causing its black hole to be very well fed at the moment. While one source describes these as elliptical galaxies with no sign of recent star formation most describe all three as blue compact S0 galaxies. From the color of the halos in my image I'd agree with the latter. The halo doesn't have the orange color most always seen with elliptical galaxies. Though there are some exceptions 3 in one spot would seem a bit too much of a coincidence to me anyway. While most galaxy clusters are populted with elliptical galaxies as their most common members this cluster seems to be mostly S0 galaxies. I son't recall seeing so many one on image before. One of the few exceptions is the face on, low surface brightness spiral south and a bit west of Arp 169. It is CGCG 428-057 a 15th magnitude galaxy. I've prepared a simple annotated chart showing distances to galaxies and quasars that are not members of the galaxy cluster that NED had red shift data for. There's a very blue quasar at 8.4 light years right beside a galaxy that is quite likely far closer that the quasar. The most distant galaxy I know of in the image is about half way toward the lower right corner. It is SDSS J221402.08+134424.9 at a magnitude of 21.1. It must be a big one for me to see it at a distance of 4,300,000,000 light-years. Some how that looks much bigger than 4.3 billion light-years. The rather bright asteroid is (88528) 2001 QU177 which is shining at about magnitude 17.4. Arp's 200" image: http://nedwww.ipac.caltech.edu/level...ig_arp169.jpeg 14" LX200R @ f/10, L=4x10', RGB=2x10'x3, STL-11000XM, Paramount ME Besides the full image at 1" per pixel I've attached a cropped version at 0.75" per pixel. Rick |
#3
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ASTRO: Arp 169 Three galaxies, one halo
that halo was easy to mistake for something else Rick
That and the paper Glen linked are quite intriguing! rdc "Rick Johnson" wrote in message . com... Arp 169 is a trio of galaxies sharing a common envelope of stars, or at least they appear to. Red shift would put these at about 340 million light years. But studies using the D-sigma method which is often quite accurate when applied to elliptical galaxies puts the distance much closer, say about 280 million light years. The group appears to be part of the ZWCl 2212.0+1326 galaxy cluster, a group of some 138 galaxies about 338 light years. If so then the red shift distance is probably correct. I suspect that the fact these are S0 galaxies and share a common halo has skewed the D-sigma calculation. Still this galaxy cluster has galaxies with red shifts that match the D-sigma value as well. In any case its a ways from us. Arp 169 is Arp's class: Galaxies (not classifiable as S or E) with diffuse counter tails. I see mostly a common envelope of stars, not a counter tail. I think Arp is referring to the somewhat north northeast extension of the halo off the upper right galaxy NGC 7236. The middle galaxy is NGC 7237 with the small galaxy to the southeast being NGC 7237C. Arp's comment; "Faint diffulse plumes coming away from two galaxies. 3C442." This would indicate he sees a plume from NGC 7237 or 7237C as well. I see a hint of one, maybe. The reference to 3C442 is because it seems to be coming from the core of NGC 7237. This could be a sign they are actually interacting causing its black hole to be very well fed at the moment. While one source describes these as elliptical galaxies with no sign of recent star formation most describe all three as blue compact S0 galaxies. From the color of the halos in my image I'd agree with the latter. The halo doesn't have the orange color most always seen with elliptical galaxies. Though there are some exceptions 3 in one spot would seem a bit too much of a coincidence to me anyway. While most galaxy clusters are populted with elliptical galaxies as their most common members this cluster seems to be mostly S0 galaxies. I son't recall seeing so many one on image before. One of the few exceptions is the face on, low surface brightness spiral south and a bit west of Arp 169. It is CGCG 428-057 a 15th magnitude galaxy. I've prepared a simple annotated chart showing distances to galaxies and quasars that are not members of the galaxy cluster that NED had red shift data for. There's a very blue quasar at 8.4 light years right beside a galaxy that is quite likely far closer that the quasar. The most distant galaxy I know of in the image is about half way toward the lower right corner. It is SDSS J221402.08+134424.9 at a magnitude of 21.1. It must be a big one for me to see it at a distance of 4,300,000,000 light-years. Some how that looks much bigger than 4.3 billion light-years. The rather bright asteroid is (88528) 2001 QU177 which is shining at about magnitude 17.4. Arp's 200" image: http://nedwww.ipac.caltech.edu/level...ig_arp169.jpeg 14" LX200R @ f/10, L=4x10', RGB=2x10'x3, STL-11000XM, Paramount ME Besides the full image at 1" per pixel I've attached a cropped version at 0.75" per pixel. 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". |
#4
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ASTRO: Arp 169 Three galaxies, one halo
No I hadn't. Thanks.
Rick On 4/26/2010 9:10 PM, Glen Youman wrote: Rick - Did you see http://adsabs.harvard.edu/abs/2007ApJ...658L..79W On Mon, 26 Apr 2010 13:16:11 -0500, Rick wrote: Arp 169 is a trio of galaxies sharing a common envelope of stars, or at least they appear to. Red shift would put these at about 340 million light years. But studies using the D-sigma method which is often quite accurate when applied to elliptical galaxies puts the distance much closer, say about 280 million light years. The group appears to be part of the ZWCl 2212.0+1326 galaxy cluster, a group of some 138 galaxies about 338 light years. If so then the red shift distance is probably correct. I suspect that the fact these are S0 galaxies and share a common halo has skewed the D-sigma calculation. Still this galaxy cluster has galaxies with red shifts that match the D-sigma value as well. In any case its a ways from us. Arp 169 is Arp's class: Galaxies (not classifiable as S or E) with diffuse counter tails. I see mostly a common envelope of stars, not a counter tail. I think Arp is referring to the somewhat north northeast extension of the halo off the upper right galaxy NGC 7236. The middle galaxy is NGC 7237 with the small galaxy to the southeast being NGC 7237C. Arp's comment; "Faint diffulse plumes coming away from two galaxies. 3C442." This would indicate he sees a plume from NGC 7237 or 7237C as well. I see a hint of one, maybe. The reference to 3C442 is because it seems to be coming from the core of NGC 7237. This could be a sign they are actually interacting causing its black hole to be very well fed at the moment. While one source describes these as elliptical galaxies with no sign of recent star formation most describe all three as blue compact S0 galaxies. From the color of the halos in my image I'd agree with the latter. The halo doesn't have the orange color most always seen with elliptical galaxies. Though there are some exceptions 3 in one spot would seem a bit too much of a coincidence to me anyway. While most galaxy clusters are populted with elliptical galaxies as their most common members this cluster seems to be mostly S0 galaxies. I son't recall seeing so many one on image before. One of the few exceptions is the face on, low surface brightness spiral south and a bit west of Arp 169. It is CGCG 428-057 a 15th magnitude galaxy. I've prepared a simple annotated chart showing distances to galaxies and quasars that are not members of the galaxy cluster that NED had red shift data for. There's a very blue quasar at 8.4 light years right beside a galaxy that is quite likely far closer that the quasar. The most distant galaxy I know of in the image is about half way toward the lower right corner. It is SDSS J221402.08+134424.9 at a magnitude of 21.1. It must be a big one for me to see it at a distance of 4,300,000,000 light-years. Some how that looks much bigger than 4.3 billion light-years. The rather bright asteroid is (88528) 2001 QU177 which is shining at about magnitude 17.4. Arp's 200" image: http://nedwww.ipac.caltech.edu/level...ig_arp169.jpeg 14" LX200R @ f/10, L=4x10', RGB=2x10'x3, STL-11000XM, Paramount ME Besides the full image at 1" per pixel I've attached a cropped version at 0.75" per pixel. 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". |
#5
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ASTRO: Arp 169 Three galaxies, one halo
These galaxies sure look like they will complete their merger soon (well,
relatively). Stefan "Rick Johnson" schrieb im Newsbeitrag . com... Arp 169 is a trio of galaxies sharing a common envelope of stars, or at least they appear to. Red shift would put these at about 340 million light years. But studies using the D-sigma method which is often quite accurate when applied to elliptical galaxies puts the distance much closer, say about 280 million light years. The group appears to be part of the ZWCl 2212.0+1326 galaxy cluster, a group of some 138 galaxies about 338 light years. If so then the red shift distance is probably correct. I suspect that the fact these are S0 galaxies and share a common halo has skewed the D-sigma calculation. Still this galaxy cluster has galaxies with red shifts that match the D-sigma value as well. In any case its a ways from us. Arp 169 is Arp's class: Galaxies (not classifiable as S or E) with diffuse counter tails. I see mostly a common envelope of stars, not a counter tail. I think Arp is referring to the somewhat north northeast extension of the halo off the upper right galaxy NGC 7236. The middle galaxy is NGC 7237 with the small galaxy to the southeast being NGC 7237C. Arp's comment; "Faint diffulse plumes coming away from two galaxies. 3C442." This would indicate he sees a plume from NGC 7237 or 7237C as well. I see a hint of one, maybe. The reference to 3C442 is because it seems to be coming from the core of NGC 7237. This could be a sign they are actually interacting causing its black hole to be very well fed at the moment. While one source describes these as elliptical galaxies with no sign of recent star formation most describe all three as blue compact S0 galaxies. From the color of the halos in my image I'd agree with the latter. The halo doesn't have the orange color most always seen with elliptical galaxies. Though there are some exceptions 3 in one spot would seem a bit too much of a coincidence to me anyway. While most galaxy clusters are populted with elliptical galaxies as their most common members this cluster seems to be mostly S0 galaxies. I son't recall seeing so many one on image before. One of the few exceptions is the face on, low surface brightness spiral south and a bit west of Arp 169. It is CGCG 428-057 a 15th magnitude galaxy. I've prepared a simple annotated chart showing distances to galaxies and quasars that are not members of the galaxy cluster that NED had red shift data for. There's a very blue quasar at 8.4 light years right beside a galaxy that is quite likely far closer that the quasar. The most distant galaxy I know of in the image is about half way toward the lower right corner. It is SDSS J221402.08+134424.9 at a magnitude of 21.1. It must be a big one for me to see it at a distance of 4,300,000,000 light-years. Some how that looks much bigger than 4.3 billion light-years. The rather bright asteroid is (88528) 2001 QU177 which is shining at about magnitude 17.4. Arp's 200" image: http://nedwww.ipac.caltech.edu/level...ig_arp169.jpeg 14" LX200R @ f/10, L=4x10', RGB=2x10'x3, STL-11000XM, Paramount ME Besides the full image at 1" per pixel I've attached a cropped version at 0.75" per pixel. 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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