Cristobal Sifon, Felipe Menanteau, Matthew Hasselfield, Tobias A. Marriage, John P. Hughes, L. Felipe Barrientos, Jorge Gonzalez, Leopoldo Infante, Graeme E. Addison, Andrew J. Baker, Nick Battaglia, J. Richard Bond, Sudeep Das, Mark J. Devlin, Joanna Dunkley, Rolando Dunner, Megan B. Gralla, Amir Hajian, Matt Hilton, Adam D. Hincks, Arthur B. Kosowsky, Danica Marsden, Kavilan Moodley, Michael D. Niemack, Michael R. Nolta, Lyman A. Page, Bruce Partridge, Erik D. Reese, Neelima Sehgal, Jon Sievers, David N. Spergel, Suzanne T. Staggs, Robert J. Thornton, Hy Trac, Edward Wollack
We present the first dynamical mass estimates and scaling relations for a
sample of Sunyaev-Zel'dovich effect (SZE) selected galaxy clusters. The sample
consists of 16 massive clusters detected with the Atacama Cosmology Telescope
(ACT) over a 455 sq deg. area of the southern sky. Deep multi-object
spectroscopic observations were taken to secure intermediate-resolution
(R~700-800) spectra and redshifts for ~60 member galaxies on average per
cluster. The dynamical masses M_200c of the clusters have been calculated using
simulation-based scaling relations between velocity dispersion and mass. The
sample has a median redshift z=0.50 and a median mass M_200c=11x10^14 Msun/h_70
with a lower limit M_200c ~ 5x10^14 Msun/h_70, consistent with the expectations
for the ACT southern sky survey. These masses are compared to the ACT SZE
properties of the sample, specifically, the central SZE amplitude y0, the
Compton signal within a 0.5' pixel y_0.5', and the integrated Compton signal
Y_200c, which we use to derive SZE-Mass scaling relations. All SZE estimators
correlate with dynamical mass with low intrinsic scatter (11%-16%), in
agreement with numerical simulations. The influence of dynamically disturbed
clusters on these scaling relations is also considered. Using the 3-dimensional
information available, we divide the sample into relaxed and disturbed clusters
and find that ~50% of the clusters are disturbed. We conclude that disturbed
systems do not significantly bias the scaling relations but might modestly
boost their scatter.
View original:
http://arxiv.org/abs/1201.0991
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