English
Related papers

Related papers: An Unsupervised Learning Approach for Quasar Conti…

200 papers

Since their first discovery, quasars have been essential probes of the distant Universe. However, due to our limited knowledge of its nature, predicting the intrinsic quasar continua has bottlenecked their usage. Existing methods of quasar…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-24 Zechang Sun , Yuan-Sen Ting , Zheng Cai

We present a novel intelligent quasar continuum neural network (iQNet), predicting the intrinsic continuum of any quasar in the rest-frame wavelength range 1020 Angstroms $\leq \lambda \leq$ 1600 Angstroms. We train this network using…

Astrophysics of Galaxies · Physics 2021-02-03 Bin Liu , Rongmon Bordoloi

The Lyman-alpha forest is a portion of the observed light spectrum of distant galactic nuclei which allows us to probe remote regions of the Universe that are otherwise inaccessible. The observed Lyman-alpha forest of a quasar light…

The quest for effective quantum feature maps for data encoding presents significant challenges, particularly due to the flat training landscapes and lengthy training processes associated with parameterised quantum circuits. To address these…

Quantum Physics · Physics 2025-08-12 Yaswitha Gujju , Romain Harang , Chao Li , Tetsuo Shibuya , Qibin Zhao

The Lyman-$\alpha$ forest refers to the series of absorption features observed in the spectra of distant quasars that are produced by neutral hydrogen in the intergalactic medium. Observed over a wide range of redshifts with both ground-…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-22 Jonás Chaves-Montero

Unlike unsupervised approaches such as autoencoders that learn to reconstruct their inputs, this paper introduces an alternative approach to unsupervised feature learning called divergent discriminative feature accumulation (DDFA) that…

Neural and Evolutionary Computing · Computer Science 2014-06-11 Paul A. Szerlip , Gregory Morse , Justin K. Pugh , Kenneth O. Stanley

Quantum architecture search (QAS) represents a fundamental challenge in quantum machine learning. Unlike previous methods that treat it as a static search process, from a perspective on QAS as an item retrieval task in vast search space, we…

Quantum Physics · Physics 2024-11-12 Lian-Hui Yu , Xiao-Yu Li , Geng Chen , Qin-Sheng Zhu , Hui Li , Guo-Wu Yang

We have employed deep neural network, or deep learning to predict the flux and the shape of the broad Ly$\alpha$ emission lines in the spectra of quasars. We use 17870 high signal-to-noise ratio (SNR > 15) quasar spectra from the Sloan…

Astrophysics of Galaxies · Physics 2020-08-05 Hassan Fathivavsari

Lensed quasars are key to many areas of study in astronomy, offering a unique probe into the intermediate and far universe. However, finding lensed quasars has proved difficult despite significant efforts from large collaborations. These…

{\it Learning finite automata} (termed as {\it model learning}) has become an important field in machine learning and has been useful realistic applications. Quantum finite automata (QFA) are simple models of quantum computers with finite…

Quantum Physics · Physics 2023-11-14 Daowen Qiu

Context. Ongoing and upcoming large spectroscopic surveys are drastically increasing the number of observed quasar spectra, requiring the development of fast and accurate automated methods to estimate spectral continua. Aims. This study…

Quasars at the redshift frontier (z > 7.0) are fundamental probes of black hole (BH) growth and evolution but notoriously difficult to identify. At these redshifts, machine learning-based selection methods have proven to be efficient, but…

Astrophysics of Galaxies · Physics 2026-05-20 F. Guarneri , J. T. Schindler , R. A. Meyer , D. Yang , J. F. Hennawi , L. Lucie-Smith , S. E. I. Bosman , F. B. Davies

Client heterogeneity poses significant challenges to the performance of Quantum Federated Learning (QFL). To overcome these limitations, we propose a new approach leveraging deep unfolding, which enables clients to autonomously optimize…

Machine Learning · Computer Science 2025-06-26 Shanika Iroshi Nanayakkara , Shiva Raj Pokhrel

Meta-forecasting is a newly emerging field which combines meta-learning and time series forecasting. The goal of meta-forecasting is to train over a collection of source time series and generalize to new time series one-at-a-time. Previous…

Machine Learning · Computer Science 2023-02-07 Mike Van Ness , Huibin Shen , Hao Wang , Xiaoyong Jin , Danielle C. Maddix , Karthick Gopalswamy

We present a method to make predictions with sets of correlated data values, in this case QSO flux spectra. We predict the continuum in the Lyman-Alpha forest of a QSO, from 1020 -- 1216 A, using the spectrum of that QSO from 1216 -- 1600 A…

Astrophysics · Physics 2009-11-10 Nao Suzuki , David Tytler , David Kirkman , John M. O'Meara , Dan Lubin

We present a new Bayesian algorithm making use of Markov Chain Monte Carlo sampling that allows us to simultaneously estimate the unknown continuum level of each quasar in an ensemble of high-resolution spectra, as well as their common…

Astrophysics of Galaxies · Physics 2017-08-09 Anna-Christina Eilers , Joseph F. Hennawi , Khee-Gan Lee

Identifying acoustic events from a continuously streaming audio source is of interest for many applications including environmental monitoring for basic research. In this scenario neither different event classes are known nor what…

Computer Vision and Pattern Recognition · Computer Science 2017-12-12 Matthias Meyer , Jan Beutel , Lothar Thiele

Factor analysis (FA) is a statistical tool for studying how observed variables with some mutual dependences can be expressed as functions of mutually independent unobserved factors, and it is widely applied throughout the psychological,…

Machine Learning · Statistics 2023-06-01 Alex Markham , Mingyu Liu , Bryon Aragam , Liam Solus

Quantum architecture search (QAS) is desired to construct a powerful and general QAS platform which can significantly accelerate quantum advantages in error-prone and depth limited quantum circuits in today Noisy Intermediate-Scale Quantum…

Quantum Physics · Physics 2022-12-02 Anqi Zhang , Shengmei Zhao

We investigate the variety in quasar UV spectra (1020-1600A) with emphasis on the weak emission lines in the Ly alpha forest region using principal component analysis (PCA). This paper is a continuation of Suzuki et al. (2005, Paper I), but…

Astrophysics · Physics 2007-05-23 Nao Suzuki
‹ Prev 1 2 3 10 Next ›