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Title: EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS

Abstract

Sky masking is unavoidable in wide-field weak-lensing observations. We study how masks affect the measurement of statistics of matter distribution probed by weak gravitational lensing. We first use 1000 cosmological ray-tracing simulations to examine in detail the impact of masked regions on the weak-lensing Minkowski Functionals (MFs). We consider actual sky masks used for a Subaru Suprime-Cam imaging survey. The masks increase the variance of the convergence field and the expected values of the MFs are biased. The bias then compromises the non-Gaussian signals induced by the gravitational growth of structure. We then explore how masks affect cosmological parameter estimation. We calculate the cumulative signal-to-noise ratio (S/N) for masked maps to study the information content of lensing MFs. We show that the degradation of S/N for masked maps is mainly determined by the effective survey area. We also perform simple {chi}{sup 2} analysis to show the impact of lensing MF bias due to masked regions. Finally, we compare ray-tracing simulations with data from a Subaru 2 deg{sup 2} survey in order to address if the observed lensing MFs are consistent with those of the standard cosmology. The resulting {chi}{sup 2}/n{sub dof} = 29.6/30 for three combined MFs, obtained with themore » mask effects taken into account, suggests that the observational data are indeed consistent with the standard {Lambda}CDM model. We conclude that the lensing MFs are a powerful probe of cosmology only if mask effects are correctly taken into account.« less

Authors:
;  [1];  [2]
  1. Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan)
  2. National Astronomical Observatory of Japan, Tokyo 181-0015 (Japan)
Publication Date:
OSTI Identifier:
22133906
Resource Type:
Journal Article
Journal Name:
Astrophysical Journal
Additional Journal Information:
Journal Volume: 774; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; CONVERGENCE; COSMOLOGY; FUNCTIONALS; GRAVITATIONAL LENSES; MASKING; MINKOWSKI SPACE; SIGNALS; SIGNAL-TO-NOISE RATIO; SIMULATION; SKY; STATISTICS

Citation Formats

Shirasaki, Masato, Yoshida, Naoki, and Hamana, Takashi, E-mail: masato.shirasaki@utap.phys.s.u-tokyo.ac.jp. EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS. United States: N. p., 2013. Web. doi:10.1088/0004-637X/774/2/111.
Shirasaki, Masato, Yoshida, Naoki, & Hamana, Takashi, E-mail: masato.shirasaki@utap.phys.s.u-tokyo.ac.jp. EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS. United States. doi:10.1088/0004-637X/774/2/111.
Shirasaki, Masato, Yoshida, Naoki, and Hamana, Takashi, E-mail: masato.shirasaki@utap.phys.s.u-tokyo.ac.jp. Tue . "EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS". United States. doi:10.1088/0004-637X/774/2/111.
@article{osti_22133906,
title = {EFFECT OF MASKED REGIONS ON WEAK-LENSING STATISTICS},
author = {Shirasaki, Masato and Yoshida, Naoki and Hamana, Takashi, E-mail: masato.shirasaki@utap.phys.s.u-tokyo.ac.jp},
abstractNote = {Sky masking is unavoidable in wide-field weak-lensing observations. We study how masks affect the measurement of statistics of matter distribution probed by weak gravitational lensing. We first use 1000 cosmological ray-tracing simulations to examine in detail the impact of masked regions on the weak-lensing Minkowski Functionals (MFs). We consider actual sky masks used for a Subaru Suprime-Cam imaging survey. The masks increase the variance of the convergence field and the expected values of the MFs are biased. The bias then compromises the non-Gaussian signals induced by the gravitational growth of structure. We then explore how masks affect cosmological parameter estimation. We calculate the cumulative signal-to-noise ratio (S/N) for masked maps to study the information content of lensing MFs. We show that the degradation of S/N for masked maps is mainly determined by the effective survey area. We also perform simple {chi}{sup 2} analysis to show the impact of lensing MF bias due to masked regions. Finally, we compare ray-tracing simulations with data from a Subaru 2 deg{sup 2} survey in order to address if the observed lensing MFs are consistent with those of the standard cosmology. The resulting {chi}{sup 2}/n{sub dof} = 29.6/30 for three combined MFs, obtained with the mask effects taken into account, suggests that the observational data are indeed consistent with the standard {Lambda}CDM model. We conclude that the lensing MFs are a powerful probe of cosmology only if mask effects are correctly taken into account.},
doi = {10.1088/0004-637X/774/2/111},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 774,
place = {United States},
year = {2013},
month = {9}
}