Galaxy Zoo Starburst Talk

Merger or cluster?

  • jim2mars by jim2mars

    Is this a cluster of spiral galaxies that are merging?

    Posted

  • JeanTate by JeanTate

    Without having a spectroscopically determined redshift - which tells us the distance from us - it's difficult to say for sure.

    For the central object and the nice, face-on spiral apparently touching it, they do have the same redshift (0.079). Which is the same as the galaxy on the left. So this is a galaxy group (not a cluster; not enough members).

    Posted

  • jim2mars by jim2mars

    Are the individual members in this group of galaxies moving away from or toward each other?

    Posted

  • JeanTate by JeanTate

    I don't think there's any way to tell, short of making a detailed model.

    For example, while the relative line-of-sight motion of each could be determined - though that may need higher resolution spectroscopy than what we have so far - there's no way to tell what the 'sideways' motion of any of them is. Nor what the distance order is (i.e. which is closest to us, which furthest), although for the central two some overlapping dust may help decide for that pair (again, a higher resolution image would be needed).

    Posted