Estimating the large-scale angular power spectrum in the presence of systematics: a case study of Sloan Digital Sky Survey quasars

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Title: Estimating the large-scale angular power spectrum in the presence of systematics: a case study of Sloan Digital Sky Survey quasars
Authors: Leistedt, B
Peiris, HV
Mortlock, DJ
Benoit-Levy, A
Pontzen, A
Item Type: Journal Article
Abstract: The angular power spectrum is a powerful statistic for analysing cosmological signals imprinted in the clustering of matter. However, current galaxy and quasar surveys cover limited portions of the sky, and are contaminated by systematics that can mimic cosmological signatures and jeopardize the interpretation of the measured power spectra. We provide a framework for obtaining unbiased estimates of the angular power spectra of large-scale structure surveys at the largest scales using quadratic estimators. The method is tested by analysing the 600 CMASS mock catalogues constructed for the Baryon Oscillation Spectroscopic Survey. We then consider the Richards et al. catalogue of photometric quasars from the sixth Data Release of the Sloan Digital Sky Survey, which is known to include significant stellar contamination and systematic uncertainties. Focusing on the sample of ultraviolet-excess sources, we show that the excess clustering power present on the largest scales can be largely mitigated by making use of improved sky masks and projecting out the modes corresponding to the principal systematics. In particular, we find that the sample of objects with photometric redshift 1.3<z~p<2.2 exhibits no evidence of contamination when using our most conservative mask and mode projection. This indicates that any residual systematics is well within the statistical uncertainties. We conclude that, using our approach, this sample can be used for cosmological studies.
Issue Date: 1-Nov-2013
Date of Acceptance: 19-Jul-2013
URI: http://hdl.handle.net/10044/1/73487
DOI: https://doi.org/10.1093/mnras/stt1359
ISSN: 0035-8711
Publisher: Oxford University Press (OUP)
Start Page: 1857
End Page: 1873
Journal / Book Title: Monthly Notices of the Royal Astronomical Society
Volume: 435
Issue: 3
Copyright Statement: © 2013 Oxford University Press. This is a pre-copy-editing, author-produced version of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version Boris Leistedt, Hiranya V. Peiris, Daniel J. Mortlock, Aurélien Benoit-Lévy, Andrew Pontzen, Estimating the large-scale angular power spectrum in the presence of systematics: a case study of Sloan Digital Sky Survey quasars, Monthly Notices of the Royal Astronomical Society, Volume 435, Issue 3, 01 November 2013, Pages 1857–1873, https://doi.org/10.1093/mnras/stt1359 is available online at: https://doi.org/10.1093/mnras/stt1359
Sponsor/Funder: Science and Technology Facilities Council (STFC)
Science and Technology Facilities Council [2006-2012]
Science and Technology Facilities Council [2006-2012]
Funder's Grant Number: ST/K001051/1
ST/K001051/1
ST/K001051/1
Keywords: Science & Technology
Physical Sciences
Astronomy & Astrophysics
galaxies: photometry
quasars: general
galaxies: statistics
large-scale structure of Universe
OSCILLATION SPECTROSCOPIC SURVEY
PHOTOMETRICALLY CLASSIFIED QUASARS
MICROWAVE-ANISOTROPY-PROBE
PRIMORDIAL NON-GAUSSIANITY
SDSS-III
DATA RELEASE
COSMOLOGICAL IMPLICATIONS
INFLATIONARY UNIVERSE
COMPONENT SEPARATION
TARGET SELECTION
Science & Technology
Physical Sciences
Astronomy & Astrophysics
galaxies: photometry
quasars: general
galaxies: statistics
large-scale structure of Universe
OSCILLATION SPECTROSCOPIC SURVEY
PHOTOMETRICALLY CLASSIFIED QUASARS
MICROWAVE-ANISOTROPY-PROBE
PRIMORDIAL NON-GAUSSIANITY
SDSS-III
DATA RELEASE
COSMOLOGICAL IMPLICATIONS
INFLATIONARY UNIVERSE
COMPONENT SEPARATION
TARGET SELECTION
astro-ph.CO
astro-ph.CO
Astronomy & Astrophysics
0201 Astronomical and Space Sciences
Publication Status: Published
Online Publication Date: 2013-09-05
Appears in Collections:Physics
Astrophysics



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