M. Shimon, Y. Rephaeli, N. Itzhaki
Statistical measures of galaxy clusters are sensitive to neutrino masses in
the sub-eV range. We explore the possibility of using cluster number counts
from the ongoing PLANCK/SZ and future cosmic-variance-limited surveys to
constrain neutrino masses from CMB data alone. The precision with which the
total neutrino mass can be determined from SZ number counts is limited mostly
by uncertainties in the clusters mass function; these are explicitly accounted
for in our forecast. We find that projected results from the PLANCK/SZ survey
can be used to determine the total neutrino mass with a ($1\sigma$) uncertainty
of 0.08-0.11 eV, assuming fiducial neutrino mass in the range 0.1-0.3 eV, if
the survey detection limit is set at the $5\sigma$ significance level. This
improves on the limits expected from PLANCK/CMB lensing measurements by a
factor 1.5-2. With a cosmic-variance-limited SZ survey we obtain ($1\sigma$)
uncertainty of 0.05-0.07 eV. Combined PLANCK and the X-ray RASS cluster
catalogs could constrain $M_{\nu}$ at the 0.04 and 0.07, assuming fiducial
neutrino masses 0.1 and 0.3 eV, respectively. A few percent uncertainty in the
mass function parameters could result in a factor of up to $\sim 50%$
degradation of our PLANCK, CVL and PLANCK+RASS forecasts. The latter two, which
significantly benefit from cluster surveys, are more prone to mass function
uncertainty. This degradation becomes less significant for neutrino masses 0.3
eV or higher. This highlights the relevance of mass function uncertainties for
cosmological parameter estimation. Our analysis shows that if the (total)
neutrino mass is close to the lower limits deduced from neutrino oscillation
experiments, cluster number counts provide a viable complimentary cosmological
probe to CMB lensing constraints on $M_{\nu}$.
View original:
http://arxiv.org/abs/1201.1803
No comments:
Post a Comment