TY - JOUR

T1 - Galaxy correlation function and local density from photometric redshifts using the stochastic order redshift technique (SORT)

AU - Kakos, James

AU - Primack, Joel R.

AU - Rodríguez-Puebla, Aldo

AU - Tejos, Nicolas

AU - Yung, L. Y.Aaron

AU - Somerville, Rachel S.

N1 - Publisher Copyright:
© 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.

PY - 2022/8/1

Y1 - 2022/8/1

N2 - The stochastic order redshift technique (sort) is a simple, efficient, and robust method to improve cosmological redshift measurements. The method relies upon having a small (?10 per cent) reference sample of high-quality redshifts. Within pencil-beam-like sub-volumes surrounding each galaxy, we use the precise dN/dz distribution of the reference sample to recover new redshifts and assign them one-To-one to galaxies such that the original rank order of redshifts is preserved. Preserving the rank order is motivated by the fact that random variables drawn from Gaussian probability density functions with different means but equal standard deviations satisfy stochastic ordering. This process is repeated for sub-volumes surrounding each galaxy in the survey. This results in every galaxy being assigned multiple 'recovered' redshifts from which a new redshift estimate is determined. An earlier paper applied sort to a mock Sloan Digital Sky Survey at z ? 0.2 and accurately recovered the two-point correlation function (2PCF) on scales ? 4 h-1Mpc. In this paper, we test the performance of sort in surveys spanning the redshift range 0.75 < z < 2.25. We used two mock surveys extracted from the Small MultiDark-Planck and Bolshoi-Planck N-body simulations with dark matter haloes that were populated by the Santa Cruz semi-Analytic model. We find that sort overall improves redshift estimates, accurately recovers the redshift-space 2PCF ?(s) on scales ? 2.5 h-1Mpc, and provides improved local density estimates in regions of average or higher density, which may allow for improved understanding of how galaxy properties relate to their environments.

AB - The stochastic order redshift technique (sort) is a simple, efficient, and robust method to improve cosmological redshift measurements. The method relies upon having a small (?10 per cent) reference sample of high-quality redshifts. Within pencil-beam-like sub-volumes surrounding each galaxy, we use the precise dN/dz distribution of the reference sample to recover new redshifts and assign them one-To-one to galaxies such that the original rank order of redshifts is preserved. Preserving the rank order is motivated by the fact that random variables drawn from Gaussian probability density functions with different means but equal standard deviations satisfy stochastic ordering. This process is repeated for sub-volumes surrounding each galaxy in the survey. This results in every galaxy being assigned multiple 'recovered' redshifts from which a new redshift estimate is determined. An earlier paper applied sort to a mock Sloan Digital Sky Survey at z ? 0.2 and accurately recovered the two-point correlation function (2PCF) on scales ? 4 h-1Mpc. In this paper, we test the performance of sort in surveys spanning the redshift range 0.75 < z < 2.25. We used two mock surveys extracted from the Small MultiDark-Planck and Bolshoi-Planck N-body simulations with dark matter haloes that were populated by the Santa Cruz semi-Analytic model. We find that sort overall improves redshift estimates, accurately recovers the redshift-space 2PCF ?(s) on scales ? 2.5 h-1Mpc, and provides improved local density estimates in regions of average or higher density, which may allow for improved understanding of how galaxy properties relate to their environments.

KW - Large-scale structure of Universe

KW - Methods: Data analysis

KW - Methods: Statistical

KW - Techniques: Photometric

KW - Techniques: Spectroscopic

UR - http://www.scopus.com/inward/record.url?scp=85133424412&partnerID=8YFLogxK

U2 - 10.1093/mnras/stac1307

DO - 10.1093/mnras/stac1307

M3 - Article

AN - SCOPUS:85133424412

SN - 0035-8711

VL - 514

SP - 1857

EP - 1878

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 2

ER -