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Title: Consequences of CCD imperfections for cosmology determined by weak lensing surveys: from laboratory measurements to cosmological parameter bias

Journal Article · · The Astrophysical Journal (Online)
 [1];  [2];  [3];  [4];  [5]
  1. Nishina Center (RIKEN), Wako (Japan); Brookhaven National Lab. (BNL), Upton, NY (United States). RIKEN Research Center
  2. Columbia Univ., New York, NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States); California Inst. of Technology (CalTech), La Canada Flintridge, CA (United States). Jet Propulsion Lab.
  5. Nishina Center (RIKEN), Wako (Japan)
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Weak gravitational lensing causes subtle changes in the apparent shapes of galaxies due to the bending of light by the gravity of foreground masses. By measuring the shapes of large numbers of galaxies (millions in recent surveys, up to tens of billions in future surveys) we can infer the parameters that determine cosmology. Imperfections in the detectors used to record images of the sky can introduce changes in the apparent shape of galaxies, which in turn can bias the inferred cosmological parameters. Here in this paper we consider the effect of two widely discussed sensor imperfections: tree-rings, due to impurity gradients which cause transverse electric fields in the Charge-Coupled Devices (CCD), and pixel-size variation, due to periodic CCD fabrication errors. These imperfections can be observed when the detectors are subject to uniform illumination (flat field images). We develop methods to determine the spurious shear and convergence (due to the imperfections) from the flat-field images. We calculate how the spurious shear when added to the lensing shear will bias the determination of cosmological parameters. We apply our methods to candidate sensors of the Large Synoptic Survey Telescope (LSST) as a timely and important example, analyzing flat field images recorded with LSST prototype CCDs in the laboratory. In conclusion, we find that tree-rings and periodic pixel-size variation present in the LSST CCDs will introduce negligible bias to cosmological parameters determined from the lensing power spectrum, specifically w,Ωm and σ8.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), High Energy Physics (HEP)
Grant/Contract Number:
SC0012704; AC02- 98CH10886; SC00112704
OSTI ID:
1260145
Alternate ID(s):
OSTI ID: 1295207
Report Number(s):
BNL-112138-2016-JA; BNL-112370-2016-JA; KA2301020
Journal Information:
The Astrophysical Journal (Online), Vol. 825, Issue 1; ISSN 1538-4357
Publisher:
Institute of Physics (IOP)Copyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 2 works
Citation information provided by
Web of Science

References (13)

Spurious shear in weak lensing with the Large Synoptic Survey Telescope journal November 2012
Physics of fully depleted CCDs journal March 2014
Challenges for precision shape measurements journal March 2014
Mapping the dark matter with weak gravitational lensing journal February 1993
Dark-energy constraints and correlations with systematics from CFHTLS weak lensing, SNLS supernovae Ia and WMAP5 journal March 2009
Consequences of thick CCDs on image processing journal April 2014
Bayesian galaxy shape measurement for weak lensing surveys - I. Methodology and a fast-fitting algorithm journal November 2007
Cosmology with weak lensing surveys journal June 2008
Impact of spurious shear on cosmological parameter estimates from weak lensing observables journal December 2014
Use of sensor characterization data to tune electrostatic model parameters for LSST sensors journal May 2015
Pixel area variation in CCDs and implications for precision photometry conference August 2008
Precision astronomy with imperfect fully depleted CCDs — an introduction and a suggested lexicon journal March 2014
Detection of weak gravitational lensing distortions of distant galaxies by cosmic dark matter at large scales journal May 2000

Cited By (1)

Quantifying systematics from the shear inversion on weak-lensing peak counts journal June 2018

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Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
cosmological parameters
cosmology: miscellaneous
cosmology: observations
instrumentation:
instrumentation: detectors