#1
|
|||
|
|||
ASTRO: Arp 96
Arp 96 falls under Arp's category for spiral galaxies with elliptical
galaxies on their arms. They are located 205 million light-years away based on their redshifts which are virtually identical. But we can't say the elliptical is on the arm of the spiral. It would be better to say it appears to be on the arm. If it really were I suspect the arm (more a plume) would be more highly distorted. Arp stated his categories as if they were fact when they were more how they appeared to him. In some cases the galaxy on a spiral's arm is now known to be a far distant galaxy. His other categories were often incorrect. Especially those that he said categorized as material ejected from the nucleus. That's not true for any in that category that I've been able to determine. Arp's comment on this pair reads: "Faint Diffuse counter arm, and arm leading to companion." These don't follow the curve of the two arms of the spiral galaxy and lie beyond them. They appear even more diffuse than the spiral which is surprisingly diffuse for a spiral to begin with. I could call them plumes rather than arms. It appears to be an old spiral in which star formation ceased several billion years ago turning it somewhat red in color as the bluer stars have all burned out and turned to faint white dwarfs, pulsars etc. that give off little light. Since it is usually the hot blue stars that give a spiral its highly detailed features it isn't surprising that without them it looks awfully fuzzy. This could be the result of an interaction far older than its encounter with the current elliptical companion. This pair is known as UGC 03536B/MCG +14-04-10 (spiral) and UGC 3536A/MCG +14-04-11 (elliptical). NED says the spiral is Sc while the Elliptical is just listed as E or E? A note at NED says of it: "Compact symmetrical object with red envelope." The pair is located in Cepheus only 3.4 degrees from the pole. Certainly it would qualify as the Arp North Pole Galaxy. Imaging this close to the pole is testament to how precisely I've achieved polar alignment. It takes extreme accuracy to go for two hours without image rotation at this declination as any who have tried it can attest. Until the storm took out my two Polaris trees I'd not been able to do any imaging in this part of the sky. The Arp 25-114 pair is less than a degree further from the pole. While very nearby I didn't get around to it until January 2012 so it will be a while before I process it. About 30 are ahead if it. This close to the pole I can ignore my rule of sticking within 2 hours of the meridian as it makes very little difference. Actually this is a triple galaxy in the WBL (White+Bliton+Bhavsar groups) and KTG (Karachentsev Isolated Triplets of Galaxies Catalogue) catalogs. The third galaxy is CGCG 362-033/MCG +14-04-014/PGC 020191 among other designations. It is the obvious spiral to the northeast. It is listed as Sa in NED. It appears to have a ring structure in my image not mentioned in the classification. This may be due to my resolution and when seen at higher resolution not a ring at all. I was unable to find any images of it on the net with even as much resolution as I have. No other galaxy in the image has a redshift at NED so I didn't prepare an annotated image. This image was taken at 0.5" per pixel. The image has been cropped however as even cropped it is 3006x2004 pixels in size. These galaxies are quite small in angular size and I took advantage of one of the very rare nights when this was possible. I've also included a crop at 2004 pixels wide same as my normal 1" per pixel images for those who prefer it smaller. Arp's image of the pair is at: http://ned.ipac.caltech.edu/level5/A...big_arp96.jpeg For his image he used 103a-D film. I used a lot of it in my film days before 2415 film was available. Still had a roll in my freezer when I gave up film work. I threw it out as it was about 20 years old as I'd changed to hypered 2415 years before. It is rather well matched to the human eye for its response covering 4700 to 6000 angstroms. So lops off the blue and red ends of the spectrum passing mostly the region our eye is most sensitive. Arp used no filter. Since these galaxies are somewhat red I'd have expected him to have used 103a-E which is more red sensitive. 14" LX200R @ f/10, L=6x10'x1 RGB=2x10', STL-11000XM, Paramount ME Rick -- Prefix is correct. Domain is arvig dot net |
#2
|
|||
|
|||
ASTRO: Arp 96
Rick,
the "S"-shaped galaxy is a beauty! Stefan "Rick Johnson" schrieb im Newsbeitrag .com... Arp 96 falls under Arp's category for spiral galaxies with elliptical galaxies on their arms. They are located 205 million light-years away based on their redshifts which are virtually identical. But we can't say the elliptical is on the arm of the spiral. It would be better to say it appears to be on the arm. If it really were I suspect the arm (more a plume) would be more highly distorted. Arp stated his categories as if they were fact when they were more how they appeared to him. In some cases the galaxy on a spiral's arm is now known to be a far distant galaxy. His other categories were often incorrect. Especially those that he said categorized as material ejected from the nucleus. That's not true for any in that category that I've been able to determine. Arp's comment on this pair reads: "Faint Diffuse counter arm, and arm leading to companion." These don't follow the curve of the two arms of the spiral galaxy and lie beyond them. They appear even more diffuse than the spiral which is surprisingly diffuse for a spiral to begin with. I could call them plumes rather than arms. It appears to be an old spiral in which star formation ceased several billion years ago turning it somewhat red in color as the bluer stars have all burned out and turned to faint white dwarfs, pulsars etc. that give off little light. Since it is usually the hot blue stars that give a spiral its highly detailed features it isn't surprising that without them it looks awfully fuzzy. This could be the result of an interaction far older than its encounter with the current elliptical companion. This pair is known as UGC 03536B/MCG +14-04-10 (spiral) and UGC 3536A/MCG +14-04-11 (elliptical). NED says the spiral is Sc while the Elliptical is just listed as E or E? A note at NED says of it: "Compact symmetrical object with red envelope." The pair is located in Cepheus only 3.4 degrees from the pole. Certainly it would qualify as the Arp North Pole Galaxy. Imaging this close to the pole is testament to how precisely I've achieved polar alignment. It takes extreme accuracy to go for two hours without image rotation at this declination as any who have tried it can attest. Until the storm took out my two Polaris trees I'd not been able to do any imaging in this part of the sky. The Arp 25-114 pair is less than a degree further from the pole. While very nearby I didn't get around to it until January 2012 so it will be a while before I process it. About 30 are ahead if it. This close to the pole I can ignore my rule of sticking within 2 hours of the meridian as it makes very little difference. Actually this is a triple galaxy in the WBL (White+Bliton+Bhavsar groups) and KTG (Karachentsev Isolated Triplets of Galaxies Catalogue) catalogs. The third galaxy is CGCG 362-033/MCG +14-04-014/PGC 020191 among other designations. It is the obvious spiral to the northeast. It is listed as Sa in NED. It appears to have a ring structure in my image not mentioned in the classification. This may be due to my resolution and when seen at higher resolution not a ring at all. I was unable to find any images of it on the net with even as much resolution as I have. No other galaxy in the image has a redshift at NED so I didn't prepare an annotated image. This image was taken at 0.5" per pixel. The image has been cropped however as even cropped it is 3006x2004 pixels in size. These galaxies are quite small in angular size and I took advantage of one of the very rare nights when this was possible. I've also included a crop at 2004 pixels wide same as my normal 1" per pixel images for those who prefer it smaller. Arp's image of the pair is at: http://ned.ipac.caltech.edu/level5/A...big_arp96.jpeg For his image he used 103a-D film. I used a lot of it in my film days before 2415 film was available. Still had a roll in my freezer when I gave up film work. I threw it out as it was about 20 years old as I'd changed to hypered 2415 years before. It is rather well matched to the human eye for its response covering 4700 to 6000 angstroms. So lops off the blue and red ends of the spectrum passing mostly the region our eye is most sensitive. Arp used no filter. Since these galaxies are somewhat red I'd have expected him to have used 103a-E which is more red sensitive. 14" LX200R @ f/10, L=6x10'x1 RGB=2x10', STL-11000XM, Paramount ME Rick -- Prefix is correct. Domain is arvig dot net |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
[sci.astro,sci.astro.seti] Contents (Astronomy Frequently Asked Questions) (0/9) | [email protected] | Astronomy Misc | 0 | May 3rd 07 01:08 AM |
[sci.astro,sci.astro.seti] Contents (Astronomy Frequently Asked Questions) (0/9) | [email protected] | Astronomy Misc | 0 | April 12th 07 01:05 AM |
[sci.astro,sci.astro.seti] Contents (Astronomy Frequently Asked Questions) (0/9) | [email protected] | Astronomy Misc | 0 | October 6th 05 02:34 AM |
[sci.astro,sci.astro.seti] Contents (Astronomy Frequently Asked Questions) (0/9) | [email protected] | Astronomy Misc | 0 | September 30th 04 02:23 AM |
[sci.astro,sci.astro.seti] Contents (Astronomy Frequently Asked Questions) (0/9) | [email protected] | SETI | 0 | September 30th 04 02:23 AM |