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We outline how redshift-space distortions (RSD) can be measured from the angular correlation function w({\theta}), of galaxies selected from photometric surveys. The natural degeneracy between RSD and galaxy bias can be minimized by…

宇宙学与河外天体物理 · 物理学 2015-03-18 Ashley J Ross , Will J Percival , Martin Crocce , Anna Cabre , Enrique Gaztanaga

The cosmological redshift of a galaxy's light is inferable from its observable properties in images. Because imaging is much easier to acquire than spectroscopic observations that would allow the identification of distinct line features,…

天体物理仪器与方法 · 物理学 2026-05-11 Luca Tortorelli , Daniel Grün

Photometric redshift estimation plays a crucial role in modern cosmological surveys for studying the universe's large-scale structures and the evolution of galaxies. Deep learning has emerged as a powerful method to produce accurate…

宇宙学与河外天体物理 · 物理学 2023-10-04 R. Ait-Ouahmed , S. Arnouts , J. Pasquet , M. Treyer , E. Bertin

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…

天体物理仪器与方法 · 物理学 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

Redshift is a key quantity for inferring cosmological model parameters. In photometric redshift estimation, cosmologists use the coarse data collected from the vast majority of galaxies to predict the redshift of individual galaxies. To…

应用统计 · 统计学 2016-04-07 Rafael Izbicki , Ann B. Lee , Peter E. Freeman

We present the results of an imaging programme of distant galaxies (z~0.8) at high spatial resolution (~0.1").We observed 7 fields of 1'*1' with the NACO Adaptive Optics system (VLT) in Ks (2.16um) band with typical V ~ 14 guide stars and…

天体物理学 · 物理学 2010-11-11 M. Huertas-Company , D. Rouan , G. Soucail , O. Le Fèvre , L. Tasca , T. Contini

The redshifts of galaxies are a key attribute that is needed for nearly all extragalactic studies. Since spectroscopic redshifts require additional telescope and human resources, millions of galaxies are known without spectroscopic…

星系天体物理 · 物理学 2021-07-21 S. Schuldt , S. H. Suyu , R. Cañameras , S. Taubenberger , T. Meinhardt , L. Leal-Taixé , B. C. Hsieh

Accurate photometric redshifts are a lynchpin for many future experiments to pin down the cosmological model and for studies of galaxy evolution. In this study, a novel sparse regression framework for photometric redshift estimation is…

天体物理仪器与方法 · 物理学 2025-06-03 Ibrahim A. Almosallam , Sam N. Lindsay , Matt J. Jarvis , Stephen J. Roberts

In order to retrieve cosmological parameters from photometric surveys, we need to estimate the distribution of the photometric redshift in the sky with excellent accuracy. We use and apply three different machine learning methods to…

宇宙学与河外天体物理 · 物理学 2025-11-13 Elcio Abdalla , Filipe B. Abdalla , Alessandro Marins , Amilcar Queiroz , Rafael M. Ribeiro , Alex S. C. Souza

We present a new scheme, $\it{galtag}$, for refining the photometric redshift measurements of faint galaxies by probabilistically tagging them to observed galaxy groups constructed from a brighter, magnitude-limited spectroscopy survey.…

星系天体物理 · 物理学 2018-07-04 P. R. Kafle , A. S. G. Robotham , S. P. Driver , S. Deeley , P. Norberg , M. J. Drinkwater , L. J. Davies

Improving distance measurements in large imaging surveys is a major challenge to better reveal the distribution of galaxies on a large scale and to link galaxy properties with their environments. Photometric redshifts can be efficiently…

We present a star/galaxy classification for the Southern Photometric Local Universe Survey (S-PLUS), based on a Machine Learning approach: the Random Forest algorithm. We train the algorithm using the S-PLUS optical photometry up to $r$=21,…

We have carried a detailed analysis on the impact of cosmological redshift in the non-parametric approach to automated galaxy morphology classification. We artificially redshifted each galaxy from the EFIGI 4458 sample (re-centred at $z…

星系天体物理 · 物理学 2018-12-04 Leonardo de Albernaz Ferreira , Fabricio Ferrari

We present an analysis of anomaly detection for machine learning redshift estimation. Anomaly detection allows the removal of poor training examples, which can adversely influence redshift estimates. Anomalous training examples may be…

宇宙学与河外天体物理 · 物理学 2016-06-16 Ben Hoyle , Markus Michael Rau , Kerstin Paech , Christopher Bonnett , Stella Seitz , Jochen Weller

We describe an Artificial Neural Network (ANN) approach to classification of galaxy images and spectra. ANNs can replicate the classification of galaxy images by a human expert to the same degree of agreement as that between two human…

天体物理学 · 物理学 2007-05-23 Ofer Lahav

We present photometric redshifts and spectral energy distribution (SED) classifications for a sample of 1542 optically identified sources detected with XMM in the COSMOS field. Our template fitting classifies 46 sources as stars and 464 as…

We describe a new method for measuring the true redshift distribution of any set of objects studied only photometrically. The angular cross-correlation between objects in a photometric sample with objects in some spectroscopic sample as a…

天体物理学 · 物理学 2009-11-13 Jeffrey A. Newman

We present results exploring the role that probabilistic deep learning models can play in cosmology from large scale astronomical surveys through estimating the distances to galaxies (redshifts) from photometry. Due to the massive scale of…

宇宙学与河外天体物理 · 物理学 2022-02-16 Evan Jones , Tuan Do , Bernie Boscoe , Yujie Wan , Zooey Nguyen , Jack Singal

In order to answer the open questions of modern cosmology and galaxy evolution theory, robust algorithms for calculating photometric redshifts (photo-z) for very large samples of galaxies are needed. Correct estimation of the various…

天体物理仪器与方法 · 物理学 2021-08-25 Oleksandra Razim , Stefano Cavuoti , Massimo Brescia , Giuseppe Riccio , Mara Salvato , Giuseppe Longo

We measure the two-point angular correlation function of a sample of 4,289,223 galaxies with r < 19.4 mag from the Sloan Digital Sky Survey as a function of photometric redshift, absolute magnitude and colour down to M_r - 5log h = -14 mag.…