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The large-scale structure is a major source of cosmological information. However, next-generation photometric galaxy surveys will only provide a distorted view of cosmic structures due to large redshift uncertainties. To address the need…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-10 Eleni Tsaprazi , Jens Jasche , Guilhem Lavaux , Florent Leclercq

We apply a combination of a Genetic Algorithms (GA) and Support Vector Machines (SVM) machine learning algorithm to solve two important problems faced by the astronomical community: star/galaxy separation, and photometric redshift…

Instrumentation and Methods for Astrophysics · Physics 2016-04-27 S. Heinis , S. Kumar , S. Gezari , W. S. Burgett , K. C. Chambers , P. W. Draper , H. Flewelling , N. Kaiser , E. A. Magnier , N. Metcalfe , C. Waters

We investigate how well the redshift distributions of galaxies sorted into photometric redshift bins can be determined from the galaxy angular two-point correlation functions. We find that the uncertainty in the reconstructed redshift…

Astrophysics · Physics 2008-11-26 M. Schneider , L. Knox , H. Zhan , A. Connolly

Forthcoming astronomical surveys are expected to detect new sources in such large numbers that measuring their spectroscopic redshift measurements will be not be practical. Thus, there is much interest in using machine learning to yield the…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 S. J. Curran

We present the first results of our application of photometric redshifts to the study of galaxy populations in high-redshift clusters. For this survey, we are examining a sample of galaxy clusters at z > 0.6 which have already been…

Astrophysics · Physics 2007-05-23 L. M. Lubin , R. J. Brunner

We investigate how well the redshift distribution of a population of extragalactic objects can be reconstructed using angular cross-correlations with a sample whose redshifts are known. We derive the minimum variance quadratic estimator,…

Cosmology and Nongalactic Astrophysics · Physics 2016-08-30 Matthew McQuinn , Martin White

This paper reports the results obtained on the photometric redshifts measurement and accuracy, and cluster tomography in the ESO Distant Cluster Survey (EDisCS) fields. Photometric redshifts were computed using two independent codes (Hyperz…

We present measurements of the redshift-dependent clustering of a DESI-like luminous red galaxy (LRG) sample selected from the Legacy Survey imaging dataset, and use the halo occupation distribution (HOD) framework to fit the clustering…

We present results of using individual galaxies' redshift probability information derived from a photometric redshift (photo-z) algorithm, SPIDERz, to identify potential catastrophic outliers in photometric redshift determinations. By using…

Astrophysics of Galaxies · Physics 2019-11-07 Evan Jones , J. Singal

Three-dimensional wide-field galaxy surveys are fundamental for cosmological studies. For higher redshifts (z > 1.0), where galaxies are too faint, quasars still trace the large-scale structure of the Universe. Since available telescope…

Instrumentation and Methods for Astrophysics · Physics 2022-09-21 Sándor Kunsági-Máté , Róbert Beck , István Szapudi , István Csabai

The apparent sizes and brightnesses of galaxies are correlated in a dipolar pattern around matter overdensities in redshift space, appearing larger on their near side and smaller on their far side. The opposite effect occurs for galaxies…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-09 Sambatra Andrianomena , Camille Bonvin , David Bacon , Philip Bull , Chris Clarkson , Roy Maartens , Teboho Moloi

We present and compare in this paper new photometric redshift catalogs of the galaxies in three public fields: the NTT Deep Field, the HDF-N and the HDF-S. Photometric redshifts have been obtained for thewhole sample, by adopting a $\chi^2$…

Astrophysics · Physics 2009-10-31 A. Fontana , S. D'Odorico , F. Poli , E. Giallongo , S. Arnouts , S. Cristiani , A. Moorwood , P. Saracco

The cross-correlation between 21-cm intensity mapping experiments and photometric surveys of galaxies (or any other cosmological tracer with a broad radial kernel) is severely degraded by the loss of long-wavelength radial modes due to…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-19 Caroline Guandalin , Isabella P. Carucci , David Alonso , Kavilan Moodley

In the context of next-generation spectroscopic galaxy surveys, new statistics of the distribution of matter are currently being developed. Among these, we investigated the angular redshift fluctuations (ARF), which probe the information…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-24 Louis Legrand , Carlos Hernández-Monteagudo , Marian Douspis , Nabila Aghanim , Raúl E. Angulo

We have measured the angular auto-correlation function of near-infrared galaxies in SERVS+DeepDrill, the Spitzer Extragalactic Representative Volume Survey and its follow-up survey of the Deep Drilling Fields, in three large fields…

We present a new approach to obtaining photometric redshifts using a kernel learning technique called Support Vector Machines (SVMs). Unlike traditional spectral energy distribution fitting, this technique requires a large and…

Astrophysics · Physics 2009-11-10 Yogesh Wadadekar

We use the overlap between multiband photometry of the Kilo-Degree Survey (KiDS) and spectroscopic data based on the Sloan Digital Sky Survey (SDSS) and Galaxy And Mass Assembly (GAMA) to infer the colour-magnitude relation of red-sequence…

Cosmology and Nongalactic Astrophysics · Physics 2019-05-13 Mohammadjavad Vakili , Maciej Bilicki , Henk Hoekstra , Nora Elisa Chisari , Christos Georgiou , Arun Kannawadi , Koen Kuijken , Angus H. Wright

We investigate the expected cosmological constraints from a combination of weak lensing and large-scale galaxy clustering using realistic redshift distributions. Introducing a systematic bias in the weak lensing redshift distributions (of…

Cosmology and Nongalactic Astrophysics · Physics 2016-11-15 S Samuroff , MA Troxel , SL Bridle , J Zuntz , N MacCrann , E Krause , T Eifler , D Kirk

We present a determination of the effects of including galaxy morphological parameters in photometric redshift estimation with an artificial neural network method. Neural networks, which recognize patterns in the information content of data…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 J. Singal , M. Shmakova , B. Gerke , R. L. Griffith , J. Lotz

We analyse a high redshift sample ($0.4<z<0.5$) of LRG's extracted from the Sloan Digital Sky Survey Data Release 4 and their surrounding structures to explore the presence of alignment effects of these bright galaxies with neighbor…

Astrophysics · Physics 2009-11-11 Emilio Donoso , Ana L. O'Mill , Diego G. Lambas