Annealing a Follow-up Program: Improvement of the Dark Energy Figure of Merit for Optical Galaxy Cluster Surveys

The precision of cosmological parameters derived from galaxy cluster surveys is limited by uncertainty in relating observable signals to cluster mass. We demonstrate that a small mass-calibration follow-up program can significantly reduce this uncertainty and improve parameter constraints, particula...

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Bibliographic Details
Published in:The Astrophysical journal 2010-04, Vol.713 (2), p.1207-1218
Main Authors: Wu, Hao-Yi, Rozo, Eduardo, Wechsler, Risa H
Format: Article
Language:English
Subjects:
ACCURACY
ALGORITHMS
ANNEALING
Astronomy
Astrophysics
CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS
COST
DISTRIBUTION
Earth, ocean, space
ENERGY
ERRORS
Exact sciences and technology
GALAXY CLUSTERS
INFORMATION
LEVELS
MASS
ORDERS
SIGNALS
TARGETS
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Summary:The precision of cosmological parameters derived from galaxy cluster surveys is limited by uncertainty in relating observable signals to cluster mass. We demonstrate that a small mass-calibration follow-up program can significantly reduce this uncertainty and improve parameter constraints, particularly when the follow-up targets are judiciously chosen. To this end, we apply a simulated annealing algorithm to maximize the dark energy information at fixed observational cost, and find that optimal follow-up strategies can reduce the observational cost required to achieve a specified precision by up to an order of magnitude. Considering clusters selected from optical imaging in the Dark Energy Survey, we find that approximately 200 low-redshift X-ray clusters or massive Sunyaev-Zel'dovich clusters can improve the dark energy figure of merit by 50%, provided that the follow-up mass measurements involve no systematic error. In practice, the actual improvement depends on (1) the uncertainty in the systematic error in follow-up mass measurements, which needs to be controlled at the 5% level to avoid severe degradation of the results; and (2) the scatter in the optical richness-mass distribution, which needs to be made as tight as possible to improve the efficacy of follow-up observations.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/713/2/1207