by Ann » Thu Sep 22, 2011 6:15 pm
APOD Robot wrote:
Linking spiral arms, two large colliding galaxies
I don't think that Arp 272 should be described as, first and foremost, two large colliding spiral galaxies. I think it can only be described as a three-galaxy system, likely consisting of one massive and two less massive galaxies.
Of the three galaxies making up this system, NGC 6050, with its large yellow bulge, is clearly the most massive. It reminds me of M81.
The galaxy at upper right, IC 1179, reminds me of NGC 7741. Like NGC 7741, IC 1179 has a long rather narrow bar, but the bar doesn't grow noticably brighter in the middle. It is just a long luminous ribbon, spouting broad bright spiral arms bursting with young blue stars.
I searched for a long time before I found something even remotely like the nameless third member of Arp 272. This third galaxy has a relatively bright bulge, which looks like a wind-blown distorted bar, with a considerable population of massive unstable stars. However, this third member of Arp 272 apparently lacks spiral arms altogether. The only galaxy I could find that is even remotely like it is the bulge of the starburst galaxy, NGC 1808.
Of course, these three galaxies are strongly entangled with one another, creatinga unique system. And speaking about this system being unique: A fourth, and possibly even a fifth, galaxy can be seen at eleven o'clock in this image, encircled by spiral arms from the brighter members of Arp 272. Can these two faint galaxies be physical parts of Arp 272? I don't feel able to offer a definite opinon, but I note that the two small galaxies appear to be slightly, but not very, reddened compared with the larger galaxies.
Thank you for this fascinating APOD! We have seen the Hubble image before, of course, but Martin Pugh's processing has certainly made the image even better.
Ann
APOD Robot wrote:
[quote]Linking spiral arms, two large colliding galaxies [/quote]
I don't think that Arp 272 should be described as, first and foremost, two large colliding spiral galaxies. I think it can only be described as a three-galaxy system, likely consisting of one massive and two less massive galaxies.
[float=left][img]http://cache2.artprintimages.com/p/MED/21/2145/X5DCD00Z/art-print/stocktrek-images-messier-81.jpg[/img][/float]
Of the three galaxies making up this system, NGC 6050, with its large yellow bulge, is clearly the most massive. It reminds me of M81.
[float=right][img]http://www.caelumobservatory.com/mlsc/n7741thumb.jpg[/img][/float]
The galaxy at upper right, IC 1179, reminds me of NGC 7741. Like NGC 7741, IC 1179 has a long rather narrow bar, but the bar doesn't grow noticably brighter in the middle. It is just a long luminous ribbon, spouting broad bright spiral arms bursting with young blue stars.
[float=left][img]http://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/NGC_1808HSTCenter.jpg/270px-NGC_1808HSTCenter.jpg[/img][/float]
I searched for a long time before I found something even remotely like the nameless third member of Arp 272. This third galaxy has a relatively bright bulge, which looks like a wind-blown distorted bar, with a considerable population of massive unstable stars. However, this third member of Arp 272 apparently lacks spiral arms altogether. The only galaxy I could find that is even remotely like it is the bulge of the starburst galaxy, NGC 1808.
Of course, these three galaxies are strongly entangled with one another, creatinga unique system. And speaking about this system being unique: A fourth, and possibly even a fifth, galaxy can be seen at eleven o'clock in this image, encircled by spiral arms from the brighter members of Arp 272. Can these two faint galaxies be physical parts of Arp 272? I don't feel able to offer a definite opinon, but I note that the two small galaxies appear to be slightly, but not very, reddened compared with the larger galaxies.
Thank you for this fascinating APOD! We have seen the Hubble image before, of course, but Martin Pugh's processing has certainly made the image even better.
Ann