MADCOWS and Extreme Galaxy Clusters

I thought I’d do a quick post just to have an excuse to post this very pretty picture I found in a press release from  JPL:

extreme cluster

This is a distant galaxy cluster found in the “Massive And Distance Clusters Of Wise Survey“, which is known by its acronym “MADCOWS”. Ho Ho Ho. If the previous link is inaccessible, because you don’t have a subscription, then don’t worry: the paper concerned is available for free on the arXiv. If the previous link isn’t inaccessible, because you do have a subscription, then do worry because you’re wasting your money…

Anyway the abstract of the paper, by Gonzalez et al., reads:

We present confirmation of the cluster MOO J1142+1527, a massive galaxy cluster discovered as part of the Massive and Distant Clusters of WISE Survey. The cluster is confirmed to lie at z = 1.19, and using the Combined Array for Research in Millimeter-wave Astronomy we robustly detect the Sunyaev–Zel’dovich (SZ) decrement at 13.2σ. The SZ data imply a mass of M200m = (1.1 ± 0.2) × 1015M, making MOO J1142+1527 the most massive galaxy cluster known at z > 1.15 and the second most massive cluster known at z > 1. For a standard ΛCDM cosmology it is further expected to be one of the ~5 most massive clusters expected to exist at z ≥ 1.19 over the entire sky. Our ongoing Spitzer program targeting ~1750 additional candidate clusters will identify comparably rich galaxy clusters over the full extragalactic sky.

I added the link to WISE, by the way.

This cluster is obviously an impressive object, and galaxy clusters are always “extreme” in the sense that they are defined to be particularly large concentrations of mass, but this one is actually in line with theoretical expectations for such objects. The following graph shows the spread of extreme cluster masses expected as a function of redshift:

If you mentally plot the mass and redshift of this beastie on the diagram you’ll see that it’s well within the comfort zone. As extreme objects go, this one is quite normal!

2 Responses to “MADCOWS and Extreme Galaxy Clusters”

  1. Phillip Helbig Says:

    Not quite the spherical, but at least the elliptical mad cow in a vacuum!

  2. Peter and others, any comments on
    http://arxiv.org/pdf/1510.05534.pdf

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