by Ann » Wed Sep 25, 2013 2:44 am
http://www.spacetelescope.org/images/potw1338a/ wrote:
Elliptical galaxies, like the yellow fuzzy objects seen in the image, are most often found close to the centres of galaxy clusters, while spirals, such as the bluish patches, are usually found to be further out and more isolated.
So the blue spirals should be further from the cluster center than the ellipticals. But in this picture, a string of blue galaxies are seen crossing the middle of the picture, apparently right across the cluster center. The galaxies are fluffy and large-looking and some of them seem rather irregular. In my amateur opinion, there is no way that several large, fluffy, irregular-looking spirals could be situated near the center of a cluster that is otherwise populated mostly by ellipticals.
If the blue galaxies are lensed background objects, we get an explanation for their irregular shapes, large sizes and positions near the cluster center. They have been lensed and magnified by the gravity of the cluster.
By the way, it is a nice picture, geckzilla.
Ann
[quote]http://www.spacetelescope.org/images/potw1338a/ wrote:
Elliptical galaxies, like the yellow fuzzy objects seen in the image, are most often found close to the centres of galaxy clusters, while spirals, such as the bluish patches, are usually found to be further out and more isolated.[/quote]
So the blue spirals should be further from the cluster center than the ellipticals. But in this picture, a string of blue galaxies are seen crossing the middle of the picture, apparently right across the cluster center. The galaxies are fluffy and large-looking and some of them seem rather irregular. In my amateur opinion, there is no way that several large, fluffy, irregular-looking spirals could be situated near the center of a cluster that is otherwise populated mostly by ellipticals.
If the blue galaxies are lensed background objects, we get an explanation for their irregular shapes, large sizes and positions near the cluster center. They have been lensed and magnified by the gravity of the cluster.
By the way, it is a nice picture, geckzilla.
Ann