A new third-order cosmic shear statistic: separating E-/B-mode correlations on a finite interval
- Creators
- Krause, Elisabeth
- Schneider, Peter
- Eifler, Tim
Abstract
Decomposing the shear signal into E and B modes properly, i.e. without leakage of B modes into the E-mode signal and vice versa, has been a long-standing problem in weak gravitational lensing. At the two-point level this problem was resolved by developing the so-called ring statistic, and later the COSEBIs; however, extending these concepts to the three-point level is far from trivial. Currently used methods to decompose shear three-point correlation functions (3PCFs) into E and B modes require knowledge of the 3PCF down to arbitrary small scales. This implies that the 3PCF needs to be modelled on scales smaller than the minimum separation of two galaxies and will subsequently be biased towards the model, or, in the absence of a model, the statistic is affected by E-/B-mode leakage (or mixing). In this paper, we derive a new third-order E-/B-mode statistic that performs the decomposition using the 3PCF only on a finite interval, and thereby is free of any E-/B-mode leakage while at the same time relying solely on information from the data. In addition, we relate this third-order ring statistic to the convergence field, thereby enabling a fast and convenient calculation of this statistic from numerical simulations. We note that our new statistic should be applicable to corresponding E-/B-mode separation problems in the cosmic microwave background polarization field.
Additional Information
© 2012 The Authors. Monthly Notices of the Royal Astronomical Society © 2012 RAS. Accepted 2012 March 26. Received 2012 March 25; in original form 2012 January 23. Article first published online: 13 Jun 2012. We thank Bhuvnesh Jain, Chris Hirata and Mike Jarvis for useful discussions. This work was supported by the Deutsche Forschungsgemeinschaft under the Transregional Collaborative Research Center TR-33 'The Dark Universe'. EK is supported by the US National Science Foundation (AST-0807337), the US Department of Energy (DE-FG03-02-ER40701) and the David and Lucile Packard Foundation.Attached Files
Published - Krause2012p19031Mon_Not_R_Astron_Soc.pdf
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Additional details
- Eprint ID
- 32930
- Resolver ID
- CaltechAUTHORS:20120806-075448383
- TR-33
- Deutsche Forschungsgemeinschaft under the Transregional Collaborative Research Center
- AST-0807337
- NSF
- DE-FG03-02-ER40701
- Department of Energy (DOE)
- David and Lucile Packard Foundation
- Created
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2012-08-06Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field