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Related papers: Unsupervised classification of SDSS galaxy spectra

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We present a new cluster catalog extracted from the Sloan Digital Sky Survey Data Release 6 (SDSS DR6) using an adaptive matched filter (AMF) cluster finder. We identify 69,173 galaxy clusters in the redshift range 0.045 $\le z <$ 0.78 in…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-12 Thad Szabo , Elena Pierpaoli , Feng Dong , Antonio Pipino , James E. Gunn

Semi-supervised semantic segmentation learns from small amounts of labelled images and large amounts of unlabelled images, which has witnessed impressive progress with the recent advance of deep neural networks. However, it often suffers…

Computer Vision and Pattern Recognition · Computer Science 2022-03-29 Dayan Guan , Jiaxing Huang , Aoran Xiao , Shijian Lu

We describe the target selection and resulting properties of a spectroscopic sample of luminous, red galaxies (LRG) from the imaging data of the Sloan Digital Sky Survey (SDSS). These galaxies are selected on the basis of color and…

We present new spectroscopic data in the field of five high-redshift (z>=0.6) candidate galaxy clusters, drawn from the EIS Cluster Candidate Catalog. A total of 327 spectra were obtained using FORS1 at the VLT, out of which 266 are…

Astrophysics · Physics 2009-11-11 L. F. Olsen , E. Zucca , S. Bardelli , C. Benoist , L. da Costa , H. E. Jørgensen , A. Biviano , M. Ramella

We present a novel approach to photometric redshifts, one that merges the advantages of both the template fitting and empirical fitting algorithms, without any of their disadvantages. This technique derives a set of templates, describing…

Astrophysics · Physics 2009-10-31 I. Csabai , A. J. Connolly , A. S. Szalay , T. Budavari

We present a novel method to estimate accurate redshifts of star-forming galaxies by measuring the flux ratio of the same emission line observed through two adjacent narrow-band filters. We apply this method to our NB912 and new NB921 data…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Masao Hayashi , Tadayuki Kodama , Yusei Koyama , Ken-ichi Tadaki , Ichi Tanaka , Rhythm Shimakawa , Yuichi Matsuda , David Sobral , Philip N. Best , Ian Smail

We explore unsupervised machine learning for galaxy morphology analyses using a combination of feature extraction with a vector-quantised variational autoencoder (VQ-VAE) and hierarchical clustering (HC). We propose a new methodology that…

Accurate relative spectrophotometry is critical for many science applications. Small wavelength scale residuals in the flux calibration can significantly impact the measurements of weak emission and absorption features in the spectra. Using…

Instrumentation and Methods for Astrophysics · Physics 2011-10-14 Renbin Yan

We describe the construction of a template set of spectral energy distributions (SEDs) for the estimation of photometric redshifts of luminous red galaxies (LRGs) with a Bayesian template fitting method. By examining the color properties of…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-24 Natascha Greisel , Stella Seitz , Niv Drory , Ralf Bender , Roberto Saglia , Jan Snigula

We present a photometric method for identifying stars, galaxies and quasars in multi-color surveys, which uses a library of >65000 color templates. The method aims for extracting the information content of object colors in a statistically…

Astrophysics · Physics 2009-06-16 C. Wolf , K. Meisenheimer , H. -J. Röser

We present the first cluster catalogue extracted from the UKIRT Infrared Deep Sky Survey Early Data Release. The catalogue is created using UKIDSS Ultra Deep Survey infrared J and K data combined with 3.6 micro-m and 4.5 micro-m Spitzer…

We present a selection of candidates of clusters and protoclusters of galaxies identified in the photometric data of the HSC-SSP Wide Public Data Release 3 (PDR3), spanning the redshift range $\rm 0.1 \leq z \leq 2$. The selection method,…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Marcelo C. Vicentin , Laerte Sodré , Michael A. Strauss , Erik V. R. de Lima , Pablo Araya-Araya

We propose a theoretical framework to analyze semi-supervised classification under the low density separation assumption in a high-dimensional regime. In particular, we introduce QLDS, a linear classification model, where the low density…

Machine Learning · Computer Science 2023-10-23 Vasilii Feofanov , Malik Tiomoko , Aladin Virmaux

We introduce a method for producing a galaxy sample unbiased by surface brightness and stellar mass, by selecting star-forming galaxies via the positions of core-collapse supernovae (CCSNe). Whilst matching $\sim$2400 supernovae from the…

Astrophysics of Galaxies · Physics 2019-01-23 Thomas M. Sedgwick , Ivan K. Baldry , Philip A. James , Lee S. Kelvin

This is the fourth of a series of papers on low X-ray luminosity galaxy clusters. The sample comprises 45 galaxy clusters with X-ray luminosities fainter than 0.7 10$^{44}$ erg s$^{-1}$ at redshifts lower than 0.2 in the regions of the…

Astrophysics of Galaxies · Physics 2019-05-17 A. L. O'Mill , M. V. Alonso , C. Valotto , J. L. Nilo Castellón

In recent years, large scale data intensive astronomical surveys have resulted in more detailed images being produced than scientists can manually classify. Even attempts to crowd-source this work will soon be outpaced by the large amount…

Machine Learning · Computer Science 2022-09-13 Ezra Fielding , Clement N. Nyirenda , Mattia Vaccari

As the first paper in a series on the study of the galaxy-galaxy lensing from Sloan Digital Sky Survey Data Release 7 (SDSS DR7), we present our image processing pipeline that corrects the systematics primarily introduced by the Point…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-15 Wentao Luo , Xiaohu Yang , Jun Zhang , Dylan Tweed , Liping Fu , H. J. Mo , Frank C. van den Bosch , Chenggang Shu , Ran Li , Nan Li , Xiangkun Liu , Chuzhong Pan , Yiran Wang , Mario Radovich

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…

Astrophysics · Physics 2009-11-10 B. C. Hsieh , H. K. C. Yee , H. Lin , M. D. Gladders

We present the first unsupervised classification of spaxels in hyperspectral images of individual galaxies. Classes identify regions by spectral similarity and thus take all the information into account that is contained in the data cubes…

Astrophysics of Galaxies · Physics 2024-05-28 Hugo Chambon , Didier Fraix-Burnet

Photometric redshifts of galaxies obtained by multi-wavelength data are widely used in photometric surveys because of its high efficiency. Although various methods have been developed, template fitting is still adopted as one of the most…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-11 Yicheng Li , Liping Fu , Zhu Chen , Zhijian Luo , Wei Du , Yan Gong , Xianmin Meng , Junhao Lu , Zhirui Tang , Pengfei Chen , Shaohua Zhang , Chenggang Shu , Xingchen Zhou , Zuhui Fan