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In this paper we present and characterize a nearest-neighbors color-matching photometric redshift estimator that features a direct relationship between the precision and accuracy of the input magnitudes and the output photometric redshifts.…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-20 Melissa L. Graham , Andrew J. Connolly , Željko Ivezić , Samuel J. Schmidt , R. Lynne Jones , Mario Jurić , Scott F. Daniel , Peter Yoachim

The Chinese Space Station Survey Telescope (CSST) aims to map the universe across an unprecedented dynamic range of stellar densities, spanning from extragalactic voids to the crowded Galactic center (e.g. a few stars and galaxies in the…

Instrumentation and Methods for Astrophysics · Physics 2026-05-19 Jinzhi Lai , Man I Lam , Jianjun Chen , Xin Zhang , Hao Tian , Xiaohan Chen , Jialu Nie , Ming Yang , Chao Liu

We use the deepest and most complete redshift catalog currently available (the Hubble Deep Field (HDF) North supplemented by new HDF South redshift data) to minimize residuals between photometric and spectroscopic redshift estimates. The…

Astrophysics · Physics 2016-08-30 M. Massarotti , A. Iovino , A. Buzzoni , D. Valls--Gabaud

The effective redshift distribution $n(z)$ of galaxies is a critical component in the study of weak gravitational lensing. Here, we introduce a new method for determining $n(z)$ for weak lensing surveys based on high-quality redshifts and…

Galaxy photometric redshift (photo-$z$) is crucial in cosmological studies, such as weak gravitational lensing and galaxy angular clustering measurements. In this work, we try to extract photo-$z$ information and construct its probability…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-16 Xingchen Zhou , Yan Gong , Xian-Min Meng , Xuelei Chen , Zhu Chen , Wei Du , Liping Fu , Zhijian Luo

Machine learning techniques, specifically the k-nearest neighbour algorithm applied to optical band colours, have had some success in predicting photometric redshifts of quasi-stellar objects (QSOs): Although the mean of differences between…

Instrumentation and Methods for Astrophysics · Physics 2020-01-29 S. J. Curran

Broad-band measurements of flux for galaxies at different redshifts measure different regions of the rest-frame galaxy spectrum. Certain astronomical questions, such as the evolution of the luminosity function of galaxies, require…

Machine learning has rose to become an important research tool in the past decade, its application has been expanded to almost if not all disciplines known to mankind. Particularly, the use of machine learning in astrophysics research had a…

Instrumentation and Methods for Astrophysics · Physics 2023-12-18 John Y. H. Soo , Ishaq Y. K. Alshuaili , Imdad Mahmud Pathi

We present a data-driven method - heteroscedastic matrix factorization, a kind of probabilistic factor analysis - for modeling or performing dimensionality reduction on observed spectra or other high-dimensional data with known but…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 P. Tsalmantza , David W. Hogg

The Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) will produce several billion photometric redshifts (photo-$z$'s), enabling cosmological analyses to select a subset of galaxies with the most accurate photo-$z$. We…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Adam Broussard , Eric Gawiser

Since the late 1970's, redshift surveys have been vital for progress in understanding large-scale structure in the Universe. The original CfA redshift survey collected spectra of 20-30 galaxies per clear night on a 1.5 meter telescope; over…

Astrophysics · Physics 2009-11-06 Marc Davis , Jeffrey Newman

DESI is a groundbreaking international project to observe more than 40 million quasars and galaxies over a 5-year period to create a 3D map of the sky. This map will enable us to probe multiple aspects of cosmology, from dark energy to…

Cosmology and Nongalactic Astrophysics · Physics 2024-06-25 Julien Taran

We present SHEEP, a new machine learning approach to the classic problem of astronomical source classification, which combines the outputs from the XGBoost, LightGBM, and CatBoost learning algorithms to create stronger classifiers. A novel…

Instrumentation and Methods for Astrophysics · Physics 2022-10-19 P. A. C. Cunha , A. Humphrey

The cosmological exploitation of modern photometric galaxy surveys requires both accurate (unbiased) and precise (narrow) redshift probability distributions derived from broadband photometry. Existing methodologies do not meet those…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Boris Leistedt , David W. Hogg , Risa H. Wechsler , Joe DeRose

We test the effectiveness of photometric redshifts based upon galaxy spectral template fitting for X-ray luminous objects, using a sample of 65 sources detected by Chandra in the field of the Caltech Faint Galaxy Redshift Survey (CFGRS). We…

Astrophysics · Physics 2009-11-07 Anthony H. Gonzalez , Thomas J. Maccarone

In this paper we introduce the \textsc{Deepz} deep learning photometric redshift (photo-$z$) code. As a test case, we apply the code to the PAU survey (PAUS) data in the COSMOS field. \textsc{Deepz} reduces the $\sigma_{68}$ scatter…

In modern astrophysics, the machine learning has increasingly gained more popularity with its incredibly powerful ability to make predictions or calculated suggestions for large amounts of data. We describe an application of the supervised…

Astrophysics of Galaxies · Physics 2018-12-26 Yu Bai , JiFeng Liu , Song Wang , Fan Yang

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

Efficiently implementing remote sensing image classification with high spatial resolution imagery can provide a significant value in Land Use and Land Cover (LULC) classification. The new advances in remote sensing and deep learning…

Computer Vision and Pattern Recognition · Computer Science 2021-12-06 Raoof Naushad , Tarunpreet Kaur , Ebrahim Ghaderpour