von Wietersheim-Kramsta, M;
Joachimi, B;
van den Busch, JL;
Heymans, C;
Hildebrandt, H;
Asgari, M;
Tr’oster, T;
... Wright, AH; + view all
(2021)
Magnification bias in galaxy surveys with complex sample selection functions.
Monthly Notices of the Royal Astronomical Society
, 504
(1)
pp. 1452-1465.
10.1093/mnras/stab1000.
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Abstract
Gravitational lensing magnification modifies the observed spatial distribution of galaxies and can severely bias cosmological probes of large-scale structure if not accurately modelled. Standard approaches to modelling this magnification bias may not be applicable in practice as many galaxy samples have complex, often implicit, selection functions. We propose and test a procedure to quantify the magnification bias induced in clustering and galaxy–galaxy lensing (GGL) signals in galaxy samples subject to a selection function beyond a simple flux limit. The method employs realistic mock data to calibrate an effective luminosity function slope, αobs, from observed galaxy counts that can then be used with the standard formalism. We demonstrate this method for two galaxy samples derived from the Baryon Oscillation Spectroscopic Survey (BOSS) in the redshift ranges 0.2 < z ≤ 0.5 and 0.5 < z ≤ 0.75, complemented by mock data built from the MICE2 simulation. We obtain αobs = 1.93 ± 0.05 and αobs = 2.62 ± 0.28 for the two BOSS samples. For BOSS-like lenses, we forecast a contribution of the magnification bias to the GGL signal between the multipole moments, ℓ, of 100 and 4600 with a cumulative signal-to-noise ratio between 0.1 and 1.1 for sources from the Kilo-Degree Survey (KiDS), between 0.4 and 2.0 for sources from the Hyper Suprime-Cam survey (HSC), and between 0.3 and 2.8 for ESA Euclid-like source samples. These contributions are significant enough to require explicit modelling in future analyses of these and similar surveys. Our code is publicly available within the MAGBET module (https://github.com/mwiet/MAGBET).
| Type: | Article |
|---|---|
| Title: | Magnification bias in galaxy surveys with complex sample selection functions |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1093/mnras/stab1000 |
| Publisher version: | https://doi.org/10.1093/mnras/stab1000 |
| Language: | English |
| Additional information: | Copyright 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited. |
| Keywords: | Gravitational lensing: weak, methods: data analysis, methods: observational |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10128380 |
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