Selfcalibration of cluster dark energy studies: Observablemass distribution
Abstract
The exponential sensitivity of cluster number counts to the properties of the dark energy implies a comparable sensitivity to not only the mean but also the actual distribution of an observablemass proxy given the true cluster mass. For example a 25% scatter in mass can provide a ∼50% change in the number counts at z∼2 for the upcoming SPT survey. Uncertainty in the scatter of this amount would degrade dark energy constraints to uninteresting levels. Given the shape of the actual mass function, the properties of the distribution may be internally monitored by the shape of the observable mass function. As a proof of principle, for a simple massindependent Gaussian distribution the scatter may be selfcalibrated to allow a measurement of the dark energy equation of state of σ(w)∼0.1. External constraints on the mass variance of the distribution that are more accurate than Δσ^{2}_{ln(M}<0.01 at z∼1 can further improve constraints by up to a factor of 2. More generally, cluster counts and their sample variance measured as a function of the observable provide internal consistency checks on the assumed form of the observablemass distribution that will protect against misinterpretation of the dark energy constraints.
 Publication:

Physical Review D
 Pub Date:
 August 2005
 DOI:
 10.1103/PhysRevD.72.043006
 arXiv:
 arXiv:astroph/0503363
 Bibcode:
 2005PhRvD..72d3006L
 Keywords:

 98.65.Cw;
 98.80.Es;
 Galaxy clusters;
 Observational cosmology;
 Astrophysics
 EPrint:
 6 pages, 6 figures, submitted to PRD