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Title: A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS

Abstract

We develop a practical methodology to remove modes from a galaxy survey power spectrum that are associated with systematic errors. We apply this to the BOSS CMASS sample, to see if it removes the excess power previously observed beyond the best-fit ΛCDM model on very large scales. We consider several possible sources of data contamination, and check whether they affect the number of targets that can be observed and the power spectrum measurements. We describe a general framework for how such knowledge can be transformed into template fields. Mode subtraction can then be used to remove these systematic contaminants at least as well as applying corrective weighting to the observed galaxies, but benefits from giving an unbiased power. Even after applying templates for all known systematics, we find a large-scale power excess, but this is reduced compared with that observed using the weights provided by the BOSS team. This excess is at much larger scales than the BAO scale and does not affect the main results of BOSS. However, it will be important for the measurement of a scale-dependent bias due to primordial non-Gaussianity. The excess is beyond that allowed by any simple model of non-Gaussianity matching Planck data, andmore » is not matched in other surveys. We show that this power excess can further be reduced but is still present using "phenomenological" templates, designed to consider further potentially unknown sources of systematic contamination. As all discrepant angular modes can be removed using "phenomenological" templates, the potentially remaining contaminant acts radially.« less

Authors:
 [1];  [2];  [3];  [3];  [4];  [5]; ORCiD logo [6];  [7]
  1. ICC, University of Barcelona, IEEC-UB, Martí i Franquès, 1, E-08028 Barcelona, Spain
  2. Department of Physics and Astronomy, University of Waterloo, 200 University Ave W, Waterloo ON N2L 3G1, Canada, Perimeter Institute for Theoretical Physics, 31 Caroline St North, Waterloo ON N2L 2Y5, Canada, Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX, UK
  3. Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX, UK
  4. Institute of Cosmology and Gravitation, University of Portsmouth, Dennis Sciama Building, Portsmouth PO1 3FX, UK, Department of Physics, Kansas State University, 116 Cardwell Hall, Manhattan, KS 66506, USA, National Abastumani Astrophysical Observatory, Ilia State University, 2A Kazbegi Ave., GE-1060 Tbilisi, Georgia
  5. ICC, University of Barcelona, IEEC-UB, Martí i Franquès, 1, E-08028 Barcelona, Spain, ICREA, Pg. Lluís Companys 23, E-08010 Barcelona, Spain
  6. Center for Cosmology and AstroParticle Physics, The Ohio State University, Columbus, OH 43210, USA
  7. ICC, University of Barcelona, IEEC-UB, Martí i Franquès, 1, E-08028 Barcelona, Spain, Department de Física Quàntica i Astrofísica, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona, Spain
Publication Date:
Research Org.:
Kansas State Univ., Manhattan, KS (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP); National Aeronautics and Space Administration (NASA); European Union (EU); Spanish MINECO
OSTI Identifier:
1479162
Alternate Identifier(s):
OSTI ID: 1611673; OSTI ID: 1656951
Grant/Contract Number:  
SC0011840; 12-EUCLID11-0004; 725327; 614030; ST/N000668/1
Resource Type:
Published Article
Journal Name:
Monthly Notices of the Royal Astronomical Society
Additional Journal Information:
Journal Name: Monthly Notices of the Royal Astronomical Society Journal Volume: 482 Journal Issue: 1; Journal ID: ISSN 0035-8711
Publisher:
Royal Astronomical Society
Country of Publication:
United Kingdom
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; Astronomy & Astrophysics; methods: statistical; large-scale structure of Universe

Citation Formats

Kalus, B., Percival, W. J., Bacon, D. J., Mueller, E-M, Samushia, L., Verde, L., Ross, A. J., and Bernal, J. L. A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS. United Kingdom: N. p., 2018. Web. https://doi.org/10.1093/mnras/sty2655.
Kalus, B., Percival, W. J., Bacon, D. J., Mueller, E-M, Samushia, L., Verde, L., Ross, A. J., & Bernal, J. L. A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS. United Kingdom. https://doi.org/10.1093/mnras/sty2655
Kalus, B., Percival, W. J., Bacon, D. J., Mueller, E-M, Samushia, L., Verde, L., Ross, A. J., and Bernal, J. L. Mon . "A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS". United Kingdom. https://doi.org/10.1093/mnras/sty2655.
@article{osti_1479162,
title = {A map-based method for eliminating systematic modes from galaxy clustering power spectra with application to BOSS},
author = {Kalus, B. and Percival, W. J. and Bacon, D. J. and Mueller, E-M and Samushia, L. and Verde, L. and Ross, A. J. and Bernal, J. L.},
abstractNote = {We develop a practical methodology to remove modes from a galaxy survey power spectrum that are associated with systematic errors. We apply this to the BOSS CMASS sample, to see if it removes the excess power previously observed beyond the best-fit ΛCDM model on very large scales. We consider several possible sources of data contamination, and check whether they affect the number of targets that can be observed and the power spectrum measurements. We describe a general framework for how such knowledge can be transformed into template fields. Mode subtraction can then be used to remove these systematic contaminants at least as well as applying corrective weighting to the observed galaxies, but benefits from giving an unbiased power. Even after applying templates for all known systematics, we find a large-scale power excess, but this is reduced compared with that observed using the weights provided by the BOSS team. This excess is at much larger scales than the BAO scale and does not affect the main results of BOSS. However, it will be important for the measurement of a scale-dependent bias due to primordial non-Gaussianity. The excess is beyond that allowed by any simple model of non-Gaussianity matching Planck data, and is not matched in other surveys. We show that this power excess can further be reduced but is still present using "phenomenological" templates, designed to consider further potentially unknown sources of systematic contamination. As all discrepant angular modes can be removed using "phenomenological" templates, the potentially remaining contaminant acts radially.},
doi = {10.1093/mnras/sty2655},
journal = {Monthly Notices of the Royal Astronomical Society},
number = 1,
volume = 482,
place = {United Kingdom},
year = {2018},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
https://doi.org/10.1093/mnras/sty2655

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Cited by: 3 works
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