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Measuring galaxy environments in large scale photometric surveys

Research output: Contribution to journalArticle

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Measuring galaxy environments in large scale photometric surveys. / Etherington, James; Thomas, Daniel.

In: Monthly Notices of the Royal Astronomical Society, Vol. 451, 21.07.2015, p. 660-679.

Research output: Contribution to journalArticle

Harvard

Etherington, J & Thomas, D 2015, 'Measuring galaxy environments in large scale photometric surveys', Monthly Notices of the Royal Astronomical Society, vol. 451, pp. 660-679. https://doi.org/10.1093/mnras/stv999

APA

Etherington, J., & Thomas, D. (2015). Measuring galaxy environments in large scale photometric surveys. Monthly Notices of the Royal Astronomical Society, 451, 660-679. https://doi.org/10.1093/mnras/stv999

Vancouver

Etherington J, Thomas D. Measuring galaxy environments in large scale photometric surveys. Monthly Notices of the Royal Astronomical Society. 2015 Jul 21;451:660-679. https://doi.org/10.1093/mnras/stv999

Author

Etherington, James ; Thomas, Daniel. / Measuring galaxy environments in large scale photometric surveys. In: Monthly Notices of the Royal Astronomical Society. 2015 ; Vol. 451. pp. 660-679.

Bibtex

@article{e54beaedb26f418f886b91f1f55655e7,
title = "Measuring galaxy environments in large scale photometric surveys",
abstract = "The properties of galaxies in the local universe have been shown to depend upon their environment. Future large scale photometric surveys such as DES and Euclid will be vital to gain insight into the evolution of galaxy properties and the role of environment. Large samples come at the cost of redshift precision and this affects the measurement of environment. We study this by measuring environments using SDSS spectroscopic and photometric redshifts and also simulated photometric redshifts with a range of uncertainties. We consider the Nth nearest neighbour and fixed aperture methods and evaluate the impact of the aperture parameters and the redshift uncertainty. We find that photometric environments have a smaller dynamic range than spectroscopic measurements because uncertain redshifts scatter galaxies from dense environments into less dense environments. At the expected redshift uncertainty of DES, 0.1, there is Spearman rank correlation coefficient of 0.4 between the measurements using the optimal parameters. We examine the galaxy red fraction as a function of mass and environment using photometric redshifts and find that the bivariate dependence is still present in the SDSS photometric measurements. We show that photometric samples with a redshift uncertainty of 0.1 must be approximately 6-16 times larger than spectroscopic samples to detect environment correlations with equivalent fractional errors.",
keywords = "astro-ph.GA, RCUK, STFC, 1244451",
author = "James Etherington and Daniel Thomas",
note = "This article has been accepted for publication in 'Monthly notices of the Royal Astronomical Society {\circledC}: [year] The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.",
year = "2015",
month = "7",
day = "21",
doi = "10.1093/mnras/stv999",
language = "English",
volume = "451",
pages = "660--679",
journal = "MNRAS",
issn = "0035-8711",
publisher = "Oxford University Press",

}

RIS

TY - JOUR

T1 - Measuring galaxy environments in large scale photometric surveys

AU - Etherington, James

AU - Thomas, Daniel

N1 - This article has been accepted for publication in 'Monthly notices of the Royal Astronomical Society ©: [year] The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

PY - 2015/7/21

Y1 - 2015/7/21

N2 - The properties of galaxies in the local universe have been shown to depend upon their environment. Future large scale photometric surveys such as DES and Euclid will be vital to gain insight into the evolution of galaxy properties and the role of environment. Large samples come at the cost of redshift precision and this affects the measurement of environment. We study this by measuring environments using SDSS spectroscopic and photometric redshifts and also simulated photometric redshifts with a range of uncertainties. We consider the Nth nearest neighbour and fixed aperture methods and evaluate the impact of the aperture parameters and the redshift uncertainty. We find that photometric environments have a smaller dynamic range than spectroscopic measurements because uncertain redshifts scatter galaxies from dense environments into less dense environments. At the expected redshift uncertainty of DES, 0.1, there is Spearman rank correlation coefficient of 0.4 between the measurements using the optimal parameters. We examine the galaxy red fraction as a function of mass and environment using photometric redshifts and find that the bivariate dependence is still present in the SDSS photometric measurements. We show that photometric samples with a redshift uncertainty of 0.1 must be approximately 6-16 times larger than spectroscopic samples to detect environment correlations with equivalent fractional errors.

AB - The properties of galaxies in the local universe have been shown to depend upon their environment. Future large scale photometric surveys such as DES and Euclid will be vital to gain insight into the evolution of galaxy properties and the role of environment. Large samples come at the cost of redshift precision and this affects the measurement of environment. We study this by measuring environments using SDSS spectroscopic and photometric redshifts and also simulated photometric redshifts with a range of uncertainties. We consider the Nth nearest neighbour and fixed aperture methods and evaluate the impact of the aperture parameters and the redshift uncertainty. We find that photometric environments have a smaller dynamic range than spectroscopic measurements because uncertain redshifts scatter galaxies from dense environments into less dense environments. At the expected redshift uncertainty of DES, 0.1, there is Spearman rank correlation coefficient of 0.4 between the measurements using the optimal parameters. We examine the galaxy red fraction as a function of mass and environment using photometric redshifts and find that the bivariate dependence is still present in the SDSS photometric measurements. We show that photometric samples with a redshift uncertainty of 0.1 must be approximately 6-16 times larger than spectroscopic samples to detect environment correlations with equivalent fractional errors.

KW - astro-ph.GA

KW - RCUK

KW - STFC

KW - 1244451

U2 - 10.1093/mnras/stv999

DO - 10.1093/mnras/stv999

M3 - Article

VL - 451

SP - 660

EP - 679

JO - MNRAS

JF - MNRAS

SN - 0035-8711

ER -

ID: 2325083