2007-08-19

dark matter halos

The only research I did on my week-long vacation off the grid was to draft a section for Peebles's and my synthesis of galaxy evolution in the cold-dark-matter paradigm. The section I drafted was on the predictions and observations of the dark-matter halos (or concentrations, virialized or otherwise) around galaxies and groups of galaxies. I think that weak and strong lensing, along with sensitive measurements of intragroup light, might put serious constraints on the cold dark matter model at small scales, because, depending on some issues of how baryons populate the halos, each of these provides some handle on the distribution of dark matter—radial distribution, large-scale anisotropy, and small-scale substructure—which is (apparently) a robust prediction of the model.

2 comments:

  1. *Maybe* there's another thing that at some point *could* be considered as a rather robust prediction of LCDM: the top-heavy IMF at high redshift.

    All the SAMs require a top-heavy IMF at z>1 to reproduce the submm counts (aka SCUBA galaxies). There is just no way you can do without it. Not even changing the cooling to a Birnboim & Dekel picture helps ...

    ReplyDelete
  2. agreed -- will look into it. Thanks for this!

    ReplyDelete