Catastrophic photometric redshift errors: weak-lensing survey requirements
dc.contributor.author | Bernstein, Gary | en_US |
dc.contributor.author | Huterer, Dragan | en_US |
dc.date.accessioned | 2011-01-13T19:37:25Z | |
dc.date.available | 2011-01-13T19:37:25Z | |
dc.date.issued | 2010-01-11 | en_US |
dc.identifier.citation | Bernstein, Gary; Huterer, Dragan; (2010). "Catastrophic photometric redshift errors: weak-lensing survey requirements." Monthly Notices of the Royal Astronomical Society 401(2): 1399-1408. <http://hdl.handle.net/2027.42/78594> | en_US |
dc.identifier.issn | 0035-8711 | en_US |
dc.identifier.issn | 1365-2966 | en_US |
dc.identifier.uri | https://hdl.handle.net/2027.42/78594 | |
dc.description.abstract | We study the sensitivity of weak-lensing surveys to the effects of catastrophic redshift errors – cases where the true redshift is mis-estimated by a significant amount. To compute the biases in cosmological parameters, we adopt an efficient linearized analysis where the redshift errors are directly related to shifts in the weak-lensing convergence power spectra. We estimate the number N spec of unbiased spectroscopic redshifts needed to determine the catastrophic error rate well enough that biases in cosmological parameters are below statistical errors of weak-lensing tomography. While the straightforward estimate of N spec is ∼10 6 , we find that using only the photometric redshifts with z ≲ 2.5 leads to a drastic reduction in N spec to ∼30 000 while negligibly increasing statistical errors in dark-energy parameters. Therefore, the size of the spectroscopic survey needed to control catastrophic errors is similar to that previously deemed necessary to constrain the core of the z s – z p distribution. We also study the efficacy of the recent proposal to measure redshift errors by cross-correlation between the photo- z and spectroscopic samples. We find that this method requires ∼10 per cent a priori knowledge of the bias and stochasticity of the outlier population, and is also easily confounded by lensing magnification bias. The cross-correlation method is therefore unlikely to supplant the need for a complete spectroscopic-redshift survey of the source population. | en_US |
dc.format.extent | 1195479 bytes | |
dc.format.extent | 3106 bytes | |
dc.format.mimetype | application/pdf | |
dc.format.mimetype | text/plain | |
dc.publisher | Blackwell Publishing Ltd | en_US |
dc.subject.other | Gravitational Lensing | en_US |
dc.title | Catastrophic photometric redshift errors: weak-lensing survey requirements | en_US |
dc.type | Article | en_US |
dc.rights.robots | IndexNoFollow | en_US |
dc.subject.hlbsecondlevel | Astronomy | en_US |
dc.subject.hlbtoplevel | Science | en_US |
dc.description.peerreviewed | Peer Reviewed | en_US |
dc.contributor.affiliationum | Department of Physics, University of Michigan, 450 Church St, Ann Arbor, MI 48109-1040, USA | en_US |
dc.contributor.affiliationother | Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104, USA | en_US |
dc.description.bitstreamurl | http://deepblue.lib.umich.edu/bitstream/2027.42/78594/1/j.1365-2966.2009.15748.x.pdf | |
dc.identifier.doi | 10.1111/j.1365-2966.2009.15748.x | en_US |
dc.identifier.source | Monthly Notices of the Royal Astronomical Society | en_US |
dc.owningcollname | Interdisciplinary and Peer-Reviewed |
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