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Related papers: Co-SOM: Co-training for photometric redshift estim…

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This work is part of a series establishing the redshift framework for the $3\times2$pt analysis of the Dark Energy Survey Year 6 (DES Y6). For DES Y6, photometric redshift distributions are estimated using self-organizing maps (SOMs),…

Classifying stars, galaxies, and quasars is essential for understanding cosmic structure and evolution; however, the vast data from modern surveys make manual classification impractical, while supervised learning methods remain constrained…

Astrophysics of Galaxies · Physics 2025-09-09 Vahid Asadi , Hosein Haghi , Akram Hasani Zonoozi

Cosmology and galaxy evolution studies with LSST, \Euclid, and {\it Roman}, will require accurate redshifts for the detected galaxies. In this study, we present improved photometric redshift estimates for galaxies using a template library…

Astrophysics of Galaxies · Physics 2020-08-06 Bomee Lee , Ranga-Ram Chary

Accurate estimation of photometric redshifts (photo-$z$) is crucial in studies of both galaxy evolution and cosmology using current and future large sky surveys. In this study, we employ Random Forest (RF), a machine learning algorithm, to…

Cosmology and Nongalactic Astrophysics · Physics 2023-12-27 Junhao Lu , Zhijian Luo , Zhu Chen , Liping Fu , Wei Du , Yan Gong , Yicheng Li , Xian-Min Meng , Zhirui Tang , Shaohua Zhang , Chenggang Shu , Xingchen Zhou , Zuhui Fan

We present a cosmic shear analysis with an improved redshift calibration for the fourth data release of the Kilo-Degree Survey (KiDS-1000) using self-organising maps (SOMs). Compared to the previous analysis of the KiDS-1000 data, we expand…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-31 J. L. van den Busch , A. H. Wright , H. Hildebrandt , M. Bilicki , M. Asgari , S. Joudaki , C. Blake , C. Heymans , A. Kannawadi , H. Y. Shan , T. Tröster

The Self-Organizing Map (SOM) is a brain-inspired neural model that is very promising for unsupervised learning, especially in embedded applications. However, it is unable to learn efficient prototypes when dealing with complex datasets. We…

Neural and Evolutionary Computing · Computer Science 2020-09-07 Lyes Khacef , Laurent Rodriguez , Benoit Miramond

We have undertaken a dedicated program of automatic source classification in the WISE database merged with SuperCOSMOS scans, comprehensively identifying galaxies, quasars and stars on most of the unconfused sky. We use the Support Vector…

Using the Horizon-AGN hydrodynamical simulation and self-organising maps (SOMs), we show how to compress the complex data structure of a cosmological simulation into a 2-d grid which is much easier to analyse. We first verify the tight…

In this paper we present photometric redshifts for 2.7 million galaxies in the XMM-LSS and COSMOS fields, both with rich optical and near-infrared data from VISTA and HyperSuprimeCam. Both template fitting (using galaxy and Active Galactic…

Astrophysics of Galaxies · Physics 2022-06-03 P. W. Hatfield , M. J. Jarvis , N. Adams , R. A. A. Bowler , B. Häußler , K. J. Duncan

We present a new method to estimate redshift distributions and galaxy-dark matter bias parameters using correlation functions in a fully data driven and self-consistent manner. Unlike other machine learning, template, or correlation…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-09 Ben Hoyle , Markus Michael Rau

In this paper we present photometric redshift (photo-$z$) estimates for the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, currently the most sensitive optical survey covering the majority of the extra-galactic sky. Our…

Astrophysics of Galaxies · Physics 2022-03-14 Kenneth J. Duncan

We present a photometric method for identifying stars, galaxies and quasars in multi-color surveys and estimating multi-color redshifts for the extragalactic objects. We use a library of >65000 color templates for comparison with observed…

Astrophysics · Physics 2009-10-31 Christian Wolf , Klaus Meisenheimer , Hermann-Josef Röser

Estimating redshifts from broadband photometry is often limited by how accurately we can map the colors of galaxies to an underlying spectral template. Current techniques utilize spectrophotometric samples of galaxies or spectra derived…

Instrumentation and Methods for Astrophysics · Physics 2025-03-11 John Franklin Crenshaw , Andrew J. Connolly

We present improved methods for using stars found in astronomical exposures to calibrate both star and galaxy colors as well as to adjust the instrument flat field. By developing a spectroscopic model for the SDSS stellar locus in…

Photometric redshifts are essential in studies of both galaxy evolution and cosmology, as they enable analyses of objects too numerous or faint for spectroscopy. The Rubin Observatory, Euclid, and Roman Space Telescope will soon provide a…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-28 Jeffrey A. Newman , Daniel Gruen

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…

Instrumentation and Methods for Astrophysics · Physics 2022-08-24 Biprateep Dey , Brett H. Andrews , Jeffrey A. Newman , Yao-Yuan Mao , Markus Michael Rau , Rongpu Zhou

While making a tremendous impact in various fields, deep neural networks usually require large amounts of labeled data for training which are expensive to collect in many applications, especially in the medical domain. Unlabeled data, on…

Computer Vision and Pattern Recognition · Computer Science 2020-02-25 Yingda Xia , Fengze Liu , Dong Yang , Jinzheng Cai , Lequan Yu , Zhuotun Zhu , Daguang Xu , Alan Yuille , Holger Roth

Deep learning models have demonstrated remarkable success in multi-organ segmentation but typically require large-scale datasets with all organs of interest annotated. However, medical image datasets are often low in sample size and only…

Computer Vision and Pattern Recognition · Computer Science 2023-11-03 Han Liu , Zhoubing Xu , Riqiang Gao , Hao Li , Jianing Wang , Guillaume Chabin , Ipek Oguz , Sasa Grbic

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…

Astrophysics of Galaxies · Physics 2021-07-21 S. Schuldt , S. H. Suyu , R. Cañameras , S. Taubenberger , T. Meinhardt , L. Leal-Taixé , B. C. Hsieh
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