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Related papers: An improved quasar detection method in EROS-2 and …

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We present the VST ATLAS Quasar Survey, consisting of $\sim1,229,000$ quasar (QSO) candidates with $16<g<22.5$ over $\sim4700$ deg$^2$. The catalogue is based on VST ATLAS$+$NEOWISE imaging surveys and aims to reach a QSO sky density of…

We present preliminary results of the quasar survey in Large Sky Area Multi- Object Fiber Spectroscopic Telescope (LAMOST) first data release (DR1), which includes pilot survey and the first year regular survey. There are 3921 quasars…

The need for the development of automatic tools to explore astronomical databases has been recognized since the inception of CCDs and modern computers. Astronomers already have developed solutions to tackle several science problems, such as…

Instrumentation and Methods for Astrophysics · Physics 2016-03-01 Karim Pichara , Pavlos Protopapas , Daniel León

This paper introduces a novel anomaly detection framework that combines the robust statistical principles of density-estimation-based anomaly detection methods with the representation-learning capabilities of deep learning models. The…

Machine Learning · Computer Science 2024-08-15 Joseph Gallego-Mejia , Oscar Bustos-Brinez , Fabio A. González

We propose a novel method to reconstruct high-resolution three-dimensional mass maps using data from photometric weak-lensing surveys. We apply an adaptive LASSO algorithm to perform a sparsity-based reconstruction on the assumption that…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-03 Xiangchong Li , Naoki Yoshida , Masamune Oguri , Shiro Ikeda , Wentao Luo

We develop and demonstrate a classification system constituted by several Support Vector Machines (SVM) classifiers, which can be applied to select quasar candidates from large sky survey projects, such as SDSS, UKIDSS, GALEX. How to…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 Nanbo Peng , Yanxia Zhang , Yongheng Zhao , Xuebing Wu

With the availability of multiwavelength, multiscale and multiepoch astronomical catalogues, the number of features to describe astronomical objects has increases. The better features we select to classify objects, the higher the…

Astrophysics · Physics 2009-09-29 Y. Zhang , Y. Zhao , D. Gao

The discovery of exoplanets has expanded our understanding of planetary systems and opened new avenues for astronomical research. In this study, we present a machine learning (ML) framework for exoplanet identification using a time-series…

Earth and Planetary Astrophysics · Physics 2025-08-14 Reihaneh Karimi , Mahdiyar Mousavi-Sadr , Mohammad H. Zhoolideh Haghighi , Fatemeh S. Tabatabaei

We describe a novel end-to-end approach using Machine Learning to reconstruct the power spectrum of cosmological density perturbations at high redshift from observed quasar spectra. State-of-the-art cosmological simulations of structure…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-21 Maria Han Veiga , Xi Meng , Oleg Y. Gnedin , Nickolay Y. Gnedin , Xun Huan

Most of object detection algorithms can be categorized into two classes: two-stage detectors and one-stage detectors. Recently, many efforts have been devoted to one-stage detectors for the simple yet effective architecture. Different from…

Computer Vision and Pattern Recognition · Computer Science 2020-04-14 Qi Qian , Lei Chen , Hao Li , Rong Jin

Recent work has found evidence for a difference in the bias and dark matter halo masses of WISE-selected obscured and unobscured quasars, implying a distinction between these populations beyond random line-of-sight effects. However, the…

Astrophysics of Galaxies · Physics 2017-06-28 Michael A. DiPompeo , Ryan C. Hickox , Sarah Eftekharzadeh , Adam D. Myers

We combine in a single framework the two complementary benefits of chi^2-template fits and empirical training sets used e.g. in neural nets: chi^2 is more reliable when its probability density functions (PDFs) are inspected for multiple…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Christian Wolf

Medical image retrieval (MIR) is a critical component of computer-aided diagnosis, yet existing systems suffer from three persistent limitations: uniform feature encoding that fails to account for the varying clinical importance of…

Computer Vision and Pattern Recognition · Computer Science 2026-03-18 Aojie Yuan

A popular technique for selecting and tuning machine learning estimators is cross-validation. Cross-validation evaluates overall model fit, usually in terms of predictive accuracy. In causal inference, the optimal choice of estimator…

Methodology · Statistics 2021-07-07 Dominik Rothenhäusler

The intense radiation emitted by luminous quasars dramatically alters the ionization state of their surrounding IGM. This so-called proximity effect extends out to tens of Mpc, and manifests as large coherent regions of enhanced…

Astrophysics of Galaxies · Physics 2019-09-25 Tobias M. Schmidt , Joseph F. Hennawi , Khee-Gan Lee , Zarija Lukic , Jose Onorbe , Martin White

This study evaluates the performance of several machine learning models for predicting hazardous near-Earth objects (NEOs) through a binary classification framework, including data scaling, power transformation, and cross-validation. Six…

Earth and Planetary Astrophysics · Physics 2025-08-22 Sunkalp Chandra

Systems exhibiting nonlinear dynamics, including but not limited to chaos, are ubiquitous across Earth Sciences such as Meteorology, Hydrology, Climate and Ecology, as well as Biology such as neural and cardiac processes. However, System…

Machine Learning · Computer Science 2020-08-14 Nishant Yadav , Sai Ravela , Auroop R. Ganguly

We describe the algorithm for selecting quasar candidates for optical spectroscopy in the Sloan Digital Sky Survey. Quasar candidates are selected via their non-stellar colors in "ugriz" broad-band photometry, and by matching unresolved…

Weakly-supervised semantic segmentation aims to reduce labeling costs by training semantic segmentation models using weak supervision, such as image-level class labels. However, most approaches struggle to produce accurate localization maps…

Computer Vision and Pattern Recognition · Computer Science 2023-04-21 Sanghyun Jo , In-Jae Yu , Kyungsu Kim

As a representative self-supervised method, contrastive learning has achieved great successes in unsupervised training of representations. It trains an encoder by distinguishing positive samples from negative ones given query anchors. These…

Computer Vision and Pattern Recognition · Computer Science 2022-03-29 Xiao Wang , Yuhang Huang , Dan Zeng , Guo-Jun Qi