English
Related papers

Related papers: Reconstructing and Classifying SDSS DR16 Galaxy Sp…

200 papers

We present a catalogue of about 6 million unresolved photometric detections in the Sloan Digital Sky Survey Seventh Data Release classifying them into stars, galaxies and quasars. We use a machine learning classifier trained on a subset of…

Instrumentation and Methods for Astrophysics · Physics 2015-05-20 Sheelu Abraham , Ninan Sajeeth Philip , Ajit Kembhavi , Yogesh G Wadadekar , Rita Sinha

We present a machine learning search for local, low-mass galaxies ($z < 0.02$ and $10^6 M_\odot < M_* < 10^9 M_\odot$) using the combined photometric data from the DESI Imaging Legacy Surveys and the WISE survey. We introduce the spectrally…

Astrophysics of Galaxies · Physics 2025-03-19 Huanian Zhang , Guangping Ye , Rongyu Wu , Dennis Zaritsky

We describe a technique for simultaneously classifying and estimating the redshift of quasars. It can separate quasars from stars in arbitrary redshift ranges, estimate full posterior distribution functions for the redshift, and naturally…

Sparse autoencoders (SAEs) have shown promise in extracting interpretable features from complex neural networks. We present one of the first applications of SAEs to dense text embeddings from large language models, demonstrating their…

Machine Learning · Computer Science 2024-08-06 Charles O'Neill , Christine Ye , Kartheik Iyer , John F. Wu

The composite spectra of quasars are widely used as templates for redshift determination, as well as for measurements of the mean transmission in Ly\alpha-forest studies, and for investigation of general spectral properties of quasars.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 G. Ivashchenko , O. Sergijenko , O. Torbaniuk

We proposed a machine learning approach to identify and distinguish dusty stellar sources employing supervised and unsupervised methods and categorizing point sources, mainly evolved stars, using photometric and spectroscopic data collected…

Over the last two decades, around 300 quasars have been discovered at $z\gtrsim6$, yet only one has identified as being strongly gravitationally lensed. We explore a new approach -- enlarging the permitted spectral parameter space, while…

Numerous ongoing and future large area surveys (e.g. DES, EUCLID, LSST, WFIRST), will increase by several orders of magnitude the volume of data that can be exploited for galaxy morphology studies. The full potential of these surveys can…

Astrophysics of Galaxies · Physics 2018-01-31 D. Tuccillo , M. Huertas-Company , E. Decencière , S. Velasco-Forero , H. Domínguez Sánchez , P. Dimauro

We study the classification and composite spectra of galaxy in the fourth data release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST). We select 40,182 spectra of galaxies from LAMOST DR4, which have…

Multi-band images of galaxies reveal a huge amount of information about their morphology and structure. However, inferring properties of the underlying stellar populations such as age, metallicity or kinematics from those images is…

Astrophysics of Galaxies · Physics 2021-11-03 Tobias Buck , Steffen Wolf

In this paper, we present a deep learning system approach to estimating luminosity, effective temperature, and surface gravity of O-type stars using the optical region of the stellar spectra. In previous work, we compare a set of machine…

Instrumentation and Methods for Astrophysics · Physics 2022-10-31 Miguel Flores R. , Luis J. Corral , Celia R. Fierro-Santillán , Silvana G. Navarro

(abridged) We describe the automated spectral classification, redshift determination, and parameter measurement pipeline in use for the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III (SDSS-III) as of Data…

We present a systematic study of the internal mass structure of early-type galaxies (ETGs) based on 106 galaxy-scale strong gravitational lenses with background quasars, all having spectroscopic redshifts. From this parent sample, we select…

Astrophysics of Galaxies · Physics 2026-02-17 Ziyu Guo , Yun Chen , Yiping Shu , Jiaze Gao , Hui Li , Zizhao He , Jun Wang

We have designed, developed, and applied a convolutional neural network (CNN) architecture using multi-task learning to search for and characterize strong HI Lya absorption in quasar spectra. Without any explicit modeling of the quasar…

Astrophysics of Galaxies · Physics 2018-02-14 David Parks , J. Xavier Prochaska , Shawfeng Dong , Zheng Cai

The wavelength dependence of atmospheric refraction causes differential chromatic refraction (DCR), whereby objects imaged at different optical/UV wavelengths are observed at slightly different positions in the plane of the detector. Strong…

Astrophysics of Galaxies · Physics 2014-11-18 Michael C. Kaczmarczik , Gordon T. Richards , Sajjan S. Mehta , David J. Schlegel

Deep convolutional neural networks (DCNNs) have become the most common solution for automatic image annotation due to their non-parametric nature, good performance, and their accessibility through libraries such as TensorFlow. Among other…

Astrophysics of Galaxies · Physics 2022-01-11 Sanchari Dhar , Lior Shamir

Machine learning can provide powerful tools to detect patterns in multi-dimensional parameter space. We use K-means -a simple yet powerful unsupervised clustering algorithm which picks out structure in unlabeled data- to study a sample of…

Astrophysics of Galaxies · Physics 2016-03-11 Aycha Tammour , Sarah C. Gallagher , Mark Daley , Gordon T. Richards

Hyperspectral image (HSI) classification is a hot topic in the remote sensing community. This paper proposes a new framework of spectral-spatial feature extraction for HSI classification, in which for the first time the concept of deep…

Computer Vision and Pattern Recognition · Computer Science 2015-11-11 Zhouhan Lin , Yushi Chen , Xing Zhao , Gang Wang

We present recent results from the Laboratory for Cosmological Data Mining (http://lcdm.astro.uiuc.edu) at the National Center for Supercomputing Applications (NCSA) to provide robust classifications and photometric redshifts for objects in…

Astrophysics · Physics 2007-10-25 Nicholas M. Ball , Robert J. Brunner , Adam D. Myers

Weak gravitational lensing is a powerful probe of the large-scale cosmic matter distribution. Wide-field galaxy surveys allow us to generate the so-called weak lensing maps, but actual observations suffer from noise due to imperfect…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-21 Masato Shirasaki , Naoki Yoshida , Shiro Ikeda