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

James Kakos, Joel R. Primack, Aldo Rodríguez-Puebla, Nicolas Tejos, L. Y.Aaron Yung, Rachel S. Somerville

Producción científica: Contribución a una revistaArtículorevisión exhaustiva

2 Citas (Scopus)


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.

Idioma originalInglés
Páginas (desde-hasta)1857-1878
Número de páginas22
PublicaciónMonthly Notices of the Royal Astronomical Society
EstadoPublicada - 1 ago. 2022


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