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相关论文: Morphology Classification and Photometric Redshift…

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We train Artificial Neural Networks to classify galaxies based solely on the morphology of the galaxy images as they appear on blue survey plates. The images are reduced and morphological features such as bulge size and the number of arms…

天体物理学 · 物理学 2015-06-24 A. Naim , O. Lahav , L. Sodre , M. C. Storrie-Lombardi

We perform an analysis of photometric redshifts estimated by using a non-representative training sets in magnitude space. We use the ANNz2 and GPz algorithms to estimate the photometric redshift both in simulations as well as in real data…

宇宙学与河外天体物理 · 物理学 2018-04-12 J. D. Rivera , B. Moraes , A. I. Merson , S. Jouvel , F. B. Abdalla , M. C. B Abdalla

We present a catalogue of photometric redshifts for galaxies from DESI Legacy Imaging Surveys, which includes $\sim0.18$ billion sources covering 14,000 ${\rm deg}^2$. The photometric redshifts, along with their uncertainties, are estimated…

星系天体物理 · 物理学 2025-02-25 Xingchen Zhou , Nan Li , Hu Zou , Yan Gong , Furen Deng , Xuelei Chen , Qian Yu , Zizhao He , Boyi Ding

Redshift measures the distance to galaxies and underlies our understanding of the origin of the Universe and galaxy evolution. Spectroscopic redshift is the gold-standard method for measuring redshift, but it requires about $1000$ times…

星系天体物理 · 物理学 2025-05-19 Andrew Lizarraga , Eric Hanchen Jiang , Jacob Nowack , Yun Qi Li , Ying Nian Wu , Bernie Boscoe , Tuan Do

Supervised artificial neural networks are used to predict useful properties of galaxies in the Sloan Digital Sky Survey, in this instance morphological classifications, spectral types and redshifts. By giving the trained networks unseen…

Handling big data has largely been a major bottleneck in traditional statistical models. Consequently, when accurate point prediction is the primary target, machine learning models are often preferred over their statistical counterparts for…

统计方法学 · 统计学 2021-04-02 Arindam Fadikar , Stefan M. Wild , Jonas Chaves-Montero

We present a new machine learning model for estimating photometric redshifts with improved accuracy for galaxies in Pan-STARRS1 data release 1. Depending on the estimation range of redshifts, this model based on neural networks can handle…

天体物理仪器与方法 · 物理学 2021-12-09 Joongoo Lee , Min-Su Shin

Several papers have recently highlighted the possibility of measuring redshift space distortions from angular auto-correlations of galaxies in photometric redshift bins. In this work we extend this idea to include as observables the…

宇宙学与河外天体物理 · 物理学 2014-11-10 Jacobo Asorey , Martin Crocce , Enrique Gaztanaga

The Red-Sequence Cluster Survey (RCS) provides a large and deep photometric catalog of galaxies in the $z'$ and $R_c$ bands for ~90 square degrees of sky, and supplemental $V$ and $B$ data have been obtained for 33.6 deg$^{2}$. We compile a…

天体物理学 · 物理学 2009-11-10 B. C. Hsieh , H. K. C. Yee , H. Lin , M. D. Gladders

We present a new non-parametric method to quantify morphologies of galaxies based on a particular family of learning machines called support vector machines. The method, that can be seen as a generalization of the classical CAS…

天体物理学 · 物理学 2009-11-13 M. Huertas-Company , D. Rouan , L. Tasca , G. Soucail , O. Le Fevre

Accurate photometric redshifts for large samples of galaxies are among the main products of modern multiband digital surveys. Over the last decade, the Sloan Digital Sky Survey (SDSS) has become a sort of benchmark against which to test the…

天体物理仪器与方法 · 物理学 2014-09-05 M. Brescia , S. Cavuoti , G. Longo , V. De Stefano

Using the Gemini Near-InfraRed Spectrograph (GNIRS), we have completed a near-infrared spectroscopic survey for K-bright galaxies at z~2.3, selected from the MUSYC survey. We derived spectroscopic redshifts from emission lines or from…

Studies of the distribution and evolution of galaxies are of fundamental importance to modern cosmology; these studies, however, are hampered by the complexity of the competing effects of spectral and density evolution. Constructing a…

天体物理学 · 物理学 2009-10-31 R. J. Brunner , A. J. Connolly , A. S. Szalay

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 $\chi^2$…

天体物理学 · 物理学 2009-10-31 A. Fontana , S. D'Odorico , F. Poli , E. Giallongo , S. Arnouts , S. Cristiani , A. Moorwood , P. Saracco

We present a technique for the estimation of photometric redshifts based on feed-forward neural networks. The Multilayer Perceptron (MLP) Artificial Neural Network is used to predict photometric redshifts in the HDF-S from an ultra deep…

The accuracy of galaxy photometric redshift (photo-$z$) can significantly affect the analysis of weak gravitational lensing measurements, especially for future high-precision surveys. In this work, we try to extract photo-$z$ information…

宇宙学与河外天体物理 · 物理学 2022-04-11 Xingchen Zhou , Yan Gong , Xian-Min Meng , Ye Cao , Xuelei Chen , Zhu Chen , Wei Du , Liping Fu , Zhijian Luo

Testing theories of hierarchical structure formation requires estimating the distribution of galaxy morphologies and its change with redshift. One aspect of this investigation involves identifying galaxies with disturbed morphologies (e.g.,…

宇宙学与河外天体物理 · 物理学 2015-06-16 P. E. Freeman , R. Izbicki , A. B. Lee , J. A. Newman , C. J. Conselice , A. M. Koekemoer , J. M. Lotz , M. Mozena

Studies of cosmology, galaxy evolution, and astronomical transients with current and next-generation wide-field imaging surveys like the Rubin Observatory Legacy Survey of Space and Time (LSST) are all critically dependent on estimates of…

天体物理仪器与方法 · 物理学 2022-08-24 Biprateep Dey , Brett H. Andrews , Jeffrey A. Newman , Yao-Yuan Mao , Markus Michael Rau , Rongpu Zhou

We release photometric redshifts, reaching $\sim$0.7, for $\sim$14M galaxies at $r\leq 20$ in the 11,500 deg$^2$ of the SDSS north and south galactic caps. These estimates were inferred from a convolution neural network (CNN) trained on…

宇宙学与河外天体物理 · 物理学 2023-10-16 M. Treyer , R. Ait-Ouahmed , J. Pasquet , S. Arnouts , E. Bertin , D. Fouchez

Given multiband photometric data from the SDSS DR6, we estimate galaxy redshifts. We employ a Random Forest trained on color features and spectroscopic redshifts from 80,000 randomly chosen primary galaxies yielding a mapping from color to…

天体物理学 · 物理学 2007-11-16 Samuel Carliles , Tamás Budavári , Sebastien Heinis , Carey Priebe , Alexander Szalay