Preprint typeset using L ATEX style emulateapj v. 04/03/99 REDSHIFT ACCURACY REQUIREMENTS FOR FUTURE SUPERNOVA AND NUMBER COUNT SURVEYS

We investigate the required redshift accuracy of type Ia supernova and cluster number-count surveys in order for the redshift uncertainties not to contribute appreciably to the dark energy parameter error budget. For the SNAP supernova experiment, we find that, without the assistance of ground-based...

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Bibliographic Details
Main Authors: Dragan Huterer, Alex Kim, Lawrence M. Krauss, Tamara Broderick
Other Authors: The Pennsylvania State University CiteSeerX Archives
Format: Text
Language:English
Published: 2008
Subjects:
Lever
South Pole
South pole
Online Access:http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.317.5376
http://arxiv.org/pdf/astro-ph/0402002v1.pdf
Description
Summary:We investigate the required redshift accuracy of type Ia supernova and cluster number-count surveys in order for the redshift uncertainties not to contribute appreciably to the dark energy parameter error budget. For the SNAP supernova experiment, we find that, without the assistance of ground-based measurements, individual supernova redshifts would need to be determined to about 0.002 or better, which is a challenging but feasible requirement for a low-resolution spectrograph. However, we find that accurate redshifts for z < 0.1 supernovae, obtained with ground-based experiments, are sufficient to immunize the results against even relatively large redshift errors at high z. For the future cluster number-count surveys such as the South Pole Telescope, Planck or DUET, we find that the purely statistical error in photometric redshift is less important, and that the irreducible, systematic bias in redshift drives the requirements. The redshift bias will have to be kept below 0.001-0.005 per redshift bin (which is determined by the filter set), depending on the sky coverage and details of the definition of the minimal mass of the survey. Furthermore, we find that X-ray surveys have a more stringent required redshift accuracy than Sunyaev-Zeldovich (SZ) effect surveys since they use a shorter lever arm in redshift; conversely, SZ surveys benefit from their high redshift reach only so long as some redshift information is available for distant (z ∼> 1) clusters. Subject headings: cosmology: theory – large-scale structure of universe 1.

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