Space Warps Talk

Points on a circle in blue galaxies

  • roel1978 by roel1978

    In several images I see these blue galaxies, like in this image, with some points spread out on a circle around the core of the galaxy. What are these? Are these caused by lensing or are they "objects" in the galaxy itself?


  • Capella05 by Capella05 moderator in response to roel1978's comment.

    They are dense star forming regions within the galaxy.

    They tend to give the galaxy a somewhat clumpy appearance as these regions are not equally distributed within the galaxy. They are always very blue, as young stars are very hot!


  • drphilmarshall by drphilmarshall scientist, admin

    These are some of the most difficult false positives to deal with - and a good example of how humans can really help out. A robot just looking for bright spots on a ring would get totally fooled by this - but we have a much better understanding of the context of the object: you can see that it's not a very massive galaxy, it has all this blue fuzz around it, and is likely merging with that other blue galaxy, so even though the arc has very lens-like symmetry, it's almost certainly not a lens. I'm collecting this in my "really really convinicing imposters" sample 😃