Galaxy clustering, photometric redshifts and diagnosis of systematics in the DES science verification data

The DES Collaboration

Research output: Contribution to journalArticle

Abstract

We study the clustering of galaxies detected at i < 22.5 in the Science Verification observations of the Dark Energy Survey (DES). Two-point correlation functions are measured using 2.3×106 galaxies over a contiguous 116 deg2 region in five bins of photometric redshift width Δz = 0.2 in the range 0.2 < z < 1.2. The impact of photometric redshift errors is assessed by comparing results using a template-based photo-z algorithm (BPZ) to a machine-learning algorithm (TPZ). A companion paper presents maps of several observational variables (e.g. seeing, sky brightness) which could modulate the galaxy density. Here we characterize and mitigate systematic errors on the measured clustering which arise from these observational variables, in addition to others such as Galactic dust and stellar contamination. After correcting for systematic effects, we measure galaxy bias over a broad range of linear scales relative to mass clustering predicted from the Planck Λ cold dark matter model, finding agreement with the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) measurements with χ2 of 4.0 (8.7) with 5 degrees of freedom for the TPZ (BPZ) redshifts. We test a 'linear bias' model, in which the galaxy clustering is a fixed multiple of the predicted non-linear dark matter clustering. The precision of the data allows us to determine that the linear bias model describes the observed galaxy clustering to 2.5 per cent accuracy down to scales at least 4-10 times smaller than those on which linear theory is expected to be sufficient.

Original languageEnglish (US)
Pages (from-to)4301-4324
Number of pages24
JournalMonthly Notices of the Royal Astronomical Society
Volume455
Issue number4
DOIs
StatePublished - Jan 1 2016

Fingerprint

dark energy
galaxies
energy
dark matter
sky brightness
dust
machine learning
France
Canada
systematic errors
science
contamination
templates
degrees of freedom
telescopes

Keywords

  • Cosmology: observations
  • Large-scale structure of universe
  • Surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Galaxy clustering, photometric redshifts and diagnosis of systematics in the DES science verification data. / The DES Collaboration.

In: Monthly Notices of the Royal Astronomical Society, Vol. 455, No. 4, 01.01.2016, p. 4301-4324.

Research output: Contribution to journalArticle

@article{8543250ec2f74f0380b06e6322e8c530,
title = "Galaxy clustering, photometric redshifts and diagnosis of systematics in the DES science verification data",
abstract = "We study the clustering of galaxies detected at i < 22.5 in the Science Verification observations of the Dark Energy Survey (DES). Two-point correlation functions are measured using 2.3×106 galaxies over a contiguous 116 deg2 region in five bins of photometric redshift width Δz = 0.2 in the range 0.2 < z < 1.2. The impact of photometric redshift errors is assessed by comparing results using a template-based photo-z algorithm (BPZ) to a machine-learning algorithm (TPZ). A companion paper presents maps of several observational variables (e.g. seeing, sky brightness) which could modulate the galaxy density. Here we characterize and mitigate systematic errors on the measured clustering which arise from these observational variables, in addition to others such as Galactic dust and stellar contamination. After correcting for systematic effects, we measure galaxy bias over a broad range of linear scales relative to mass clustering predicted from the Planck Λ cold dark matter model, finding agreement with the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) measurements with χ2 of 4.0 (8.7) with 5 degrees of freedom for the TPZ (BPZ) redshifts. We test a 'linear bias' model, in which the galaxy clustering is a fixed multiple of the predicted non-linear dark matter clustering. The precision of the data allows us to determine that the linear bias model describes the observed galaxy clustering to 2.5 per cent accuracy down to scales at least 4-10 times smaller than those on which linear theory is expected to be sufficient.",
keywords = "Cosmology: observations, Large-scale structure of universe, Surveys",
author = "{The DES Collaboration} and M. Crocce and J. Carretero and Bauer, {A. H.} and Ross, {A. J.} and I. Sevilla-Noarbe and T. Giannantonio and F. Sobreira and J. Sanchez and E. Gaztanaga and {Carrasco Kind}, M. and C. S{\'a}nchez and C. Bonnett and A. Benoit-L{\'e}vy and Kind, {Matias Carrasco} and {Carnero Rosell}, A. and R. Cawthon and P. Fosalba and Brunner, {Robert J} and Kim, {E. J.} and B. Leistedt and R. Miquel and Peiris, {H. V.} and Percival, {W. J.} and R. Rosenfeld and Rykoff, {E. S.} and E. S{\'a}nchez and T. Abbott and Abdalla, {F. B.} and S. Allam and M. Banerji and Bernstein, {G. M.} and E. Bertin and D. Brooks and E. Buckley-Geer and Burke, {D. L.} and D. Capozzi and Castander, {F. J.} and Cunha, {C. E.} and D'Andrea, {C. B.} and {Da Costa}, {L. N.} and S. Desai and Diehl, {H. T.} and Eifler, {T. F.} and Evrard, {A. E.} and {Fausti Neto}, A. and E. Fernandez and Finley, {D. A.} and B. Flaugher and J. Frieman and Thaler, {Jon J}",
year = "2016",
month = "1",
day = "1",
doi = "10.1093/mnras/stv2590",
language = "English (US)",
volume = "455",
pages = "4301--4324",
journal = "Monthly Notices of the Royal Astronomical Society",
issn = "0035-8711",
publisher = "Oxford University Press",
number = "4",

}

TY - JOUR

T1 - Galaxy clustering, photometric redshifts and diagnosis of systematics in the DES science verification data

AU - The DES Collaboration

AU - Crocce, M.

AU - Carretero, J.

AU - Bauer, A. H.

AU - Ross, A. J.

AU - Sevilla-Noarbe, I.

AU - Giannantonio, T.

AU - Sobreira, F.

AU - Sanchez, J.

AU - Gaztanaga, E.

AU - Carrasco Kind, M.

AU - Sánchez, C.

AU - Bonnett, C.

AU - Benoit-Lévy, A.

AU - Kind, Matias Carrasco

AU - Carnero Rosell, A.

AU - Cawthon, R.

AU - Fosalba, P.

AU - Brunner, Robert J

AU - Kim, E. J.

AU - Leistedt, B.

AU - Miquel, R.

AU - Peiris, H. V.

AU - Percival, W. J.

AU - Rosenfeld, R.

AU - Rykoff, E. S.

AU - Sánchez, E.

AU - Abbott, T.

AU - Abdalla, F. B.

AU - Allam, S.

AU - Banerji, M.

AU - Bernstein, G. M.

AU - Bertin, E.

AU - Brooks, D.

AU - Buckley-Geer, E.

AU - Burke, D. L.

AU - Capozzi, D.

AU - Castander, F. J.

AU - Cunha, C. E.

AU - D'Andrea, C. B.

AU - Da Costa, L. N.

AU - Desai, S.

AU - Diehl, H. T.

AU - Eifler, T. F.

AU - Evrard, A. E.

AU - Fausti Neto, A.

AU - Fernandez, E.

AU - Finley, D. A.

AU - Flaugher, B.

AU - Frieman, J.

AU - Thaler, Jon J

PY - 2016/1/1

Y1 - 2016/1/1

N2 - We study the clustering of galaxies detected at i < 22.5 in the Science Verification observations of the Dark Energy Survey (DES). Two-point correlation functions are measured using 2.3×106 galaxies over a contiguous 116 deg2 region in five bins of photometric redshift width Δz = 0.2 in the range 0.2 < z < 1.2. The impact of photometric redshift errors is assessed by comparing results using a template-based photo-z algorithm (BPZ) to a machine-learning algorithm (TPZ). A companion paper presents maps of several observational variables (e.g. seeing, sky brightness) which could modulate the galaxy density. Here we characterize and mitigate systematic errors on the measured clustering which arise from these observational variables, in addition to others such as Galactic dust and stellar contamination. After correcting for systematic effects, we measure galaxy bias over a broad range of linear scales relative to mass clustering predicted from the Planck Λ cold dark matter model, finding agreement with the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) measurements with χ2 of 4.0 (8.7) with 5 degrees of freedom for the TPZ (BPZ) redshifts. We test a 'linear bias' model, in which the galaxy clustering is a fixed multiple of the predicted non-linear dark matter clustering. The precision of the data allows us to determine that the linear bias model describes the observed galaxy clustering to 2.5 per cent accuracy down to scales at least 4-10 times smaller than those on which linear theory is expected to be sufficient.

AB - We study the clustering of galaxies detected at i < 22.5 in the Science Verification observations of the Dark Energy Survey (DES). Two-point correlation functions are measured using 2.3×106 galaxies over a contiguous 116 deg2 region in five bins of photometric redshift width Δz = 0.2 in the range 0.2 < z < 1.2. The impact of photometric redshift errors is assessed by comparing results using a template-based photo-z algorithm (BPZ) to a machine-learning algorithm (TPZ). A companion paper presents maps of several observational variables (e.g. seeing, sky brightness) which could modulate the galaxy density. Here we characterize and mitigate systematic errors on the measured clustering which arise from these observational variables, in addition to others such as Galactic dust and stellar contamination. After correcting for systematic effects, we measure galaxy bias over a broad range of linear scales relative to mass clustering predicted from the Planck Λ cold dark matter model, finding agreement with the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) measurements with χ2 of 4.0 (8.7) with 5 degrees of freedom for the TPZ (BPZ) redshifts. We test a 'linear bias' model, in which the galaxy clustering is a fixed multiple of the predicted non-linear dark matter clustering. The precision of the data allows us to determine that the linear bias model describes the observed galaxy clustering to 2.5 per cent accuracy down to scales at least 4-10 times smaller than those on which linear theory is expected to be sufficient.

KW - Cosmology: observations

KW - Large-scale structure of universe

KW - Surveys

UR - http://www.scopus.com/inward/record.url?scp=84959085957&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84959085957&partnerID=8YFLogxK

U2 - 10.1093/mnras/stv2590

DO - 10.1093/mnras/stv2590

M3 - Article

VL - 455

SP - 4301

EP - 4324

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 4

ER -