The Atacama Cosmology Telescope: Sunyaev-Zel'dovich Selected Galaxy Clusters at 148 GHz from Three Seasons of Data. (arXiv:1301.0816v1 [astro-ph.CO])

The Atacama Cosmology Telescope: Sunyaev-Zel'dovich Selected Galaxy Clusters at 148 GHz from Three Seasons of Data. (arXiv:1301.0816v1 [astro-ph.CO]):
[Abridged] We present a catalog of 68 galaxy clusters, of which 19 are new
discoveries, detected via the Sunyaev-Zel'dovich effect (SZ) at 148 GHz in the
Atacama Cosmology Telescope (ACT) survey of 504 square degrees on the celestial
equator. A subsample of 48 clusters within the 270 square degree region
overlapping SDSS Stripe 82 is estimated to be 90% complete for M_500c > 4.5e14
Msun and 0.15 < z < 0.8. While matched filters are used to detect the clusters,
the sample is studied further through a "Profile Based Amplitude Analysis"
using a single filter at a fixed \theta_500 = 5.9' angular scale. This new
approach takes advantage of the "Universal Pressure Profile" (UPP) to break the
degeneracy between the cluster extent (R_500) and the integrated Compton
parameter (Y_500). The UPP scalings are found to be nearly identical to an
adiabatic model, while a model incorporating non-thermal pressure better
matches dynamical mass measurements and masses from the South Pole Telescope. A
complete, high signal to noise ratio subsample of 15 ACT clusters is used to
obtain cosmological constraints. We first confirm that constraints from SZ data
are limited by uncertainty in the scaling relation parameters rather than
sample size or measurement uncertainty. We next add in seven clusters from the
ACT Southern survey, including their dynamical mass measurements based on
galaxy velocity dispersions. In combination with WMAP7 these data
simultaneously constrain the scaling relation and cosmological parameters,
yielding \sigma_8 = 0.829 \pm 0.024 and \Omega_m = 0.292 \pm 0.025. The results
include marginalization over a 15% bias in dynamical mass relative to the true
halo mass. In an extension to LCDM that incorporates non-zero neutrino mass
density, we combine our data with WMAP7+BAO+Hubble constant measurements to
constrain \Sigma m_\nu < 0.29 eV (95% C. L.).