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Related papers: Exploring the Spectral Space of Low Redshift QSOs

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We present a bifidelity Karhunen-Lo\`eve expansion (KLE) surrogate model for field-valued quantities of interest (QoIs) under uncertain inputs. The approach combines the spectral efficiency of the KLE with polynomial chaos expansions (PCEs)…

Machine Learning · Statistics 2025-11-07 Aniket Jivani , Cosmin Safta , Beckett Y. Zhou , Xun Huan

We have carried out a high spectral resolution line survey towards the Orion Kleinmann-Low (KL) cluster from 44-188 um. The observations were taken with the Long Wavelength Spectrometer (LWS) in Fabry-Perot mode, on board the Infrared Space…

The previously established LOUPE (Learning-based Optimization of the Under-sampling Pattern) framework for optimizing the k-space sampling pattern in MRI was extended in three folds: firstly, fully sampled multi-coil k-space data from the…

Image and Video Processing · Electrical Eng. & Systems 2020-07-30 Jinwei Zhang , Hang Zhang , Alan Wang , Qihao Zhang , Mert Sabuncu , Pascal Spincemaille , Thanh D. Nguyen , Yi Wang

In this article, we conduct a sequential study of possible observable images of black hole simulators described by two recently obtained rotating geometries in Einstein gravity, minimally coupled to a scalar field. One of them, "Kerr-like"…

General Relativity and Quantum Cosmology · Physics 2022-08-31 Igor Bogush , Dmitri Gal'tsov , Galin Gyulchev , Kirill Kobialko , Petya Nedkova , Tsvetan Vetsov

Here we apply hyperspectral bright field imaging to collect computed tomographic images with excellent energy resolution (800 eV), applying it for the first time to map the distribution of stain in a fixed biological sample through its…

In this paper we develop a Multilevel Orthogonal Subspace (MOS) Karhunen-Loeve feature theory based on stochastic tensor spaces, for the construction of robust machine learning features. Training data are treated as instances of a random…

Spectrum sensing is the major challenge in the cognitive radio (CR). We propose to learn local feature and use it as the prior knowledge to improve the detection performance. We define the local feature as the leading eigenvector derived…

Information Theory · Computer Science 2011-04-13 Peng Zhang , Robert Qiu

We use quantum-logic spectroscopy (QLS) and interrogate rotational transitions of a single CaH+ ion with a highly coherent frequency comb, achieving a fractional statistical uncertainty for a transition line center of 4 x 10^-13. We also…

The plethora of spectra of OB-type stars in observatory archives and the much larger numbers to come from the WEAVE and 4MOST spectroscopic facilities require efficient, but also accurate and precise methods for (semi)automatic quantitative…

Solar and Stellar Astrophysics · Physics 2026-04-06 P. Aschenbrenner , N. Przybilla

(abridged) We develop a tool for the automated spectral classification of OB stars according to their sub-types. We use the regular Random Forest (RF) algorithm, the Probabilistic RF (PRF), and we introduce the KDE-RF method which is a…

Solar and Stellar Astrophysics · Physics 2022-01-12 E. Kyritsis , G. Maravelias , A. Zezas , P. Bonfini , K. Kovlakas , P. Reig

We propose a novel sparse representation for heavily underdetermined multichannel sound mixtures, i.e., with much more sources than microphones. The proposed approach operates in the complex Fourier domain, thus preserving spatial…

Sound · Computer Science 2014-10-10 Antoine Deleforge , Walter Kellermann

Black-hole spectroscopy aims to infer the fundamental properties of black holes by analysing the spectrum of gravitational waves emitted as they settle into equilibrium. These resonances, known as quasinormal modes (QNMs), decay rapidly,…

General Relativity and Quantum Cosmology · Physics 2026-04-22 Pietro Smaniotto , Leonardo Solidoro , Patrik Švančara , Sam Patrick , Maurício Richartz , Carlo F. Barenghi , Ruth Gregory , Silke Weinfurtner

Low-loss electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope (STEM) probes the valence electron density and relevant optoelectronic properties such as band gap energies and other band structure…

Materials Science · Physics 2018-11-20 Alberto Eljarrat , Christoph T. Koch

Q-LET is a FORTRAN 77 code that enables a quick estimate of the gravitational lensing effects on a point- or an extended source. The user provided input consists of the redshifts, angular positions relative to the source, mass or velocity…

Astrophysics · Physics 2009-11-10 Christofer Gunnarsson

We study test-particle dynamics in the equatorial plane of a Kerr-Bertotti-Robinson black hole (BH) immersed in a cloud of strings (CS), with mass M , rotation a, magnetic parameter B, and string parameter {\alpha}. Using the Hamilton…

High Energy Astrophysical Phenomena · Physics 2026-05-12 Faizuddin Ahmed , Orhan Donmez , Ahmad Al-Badawi , Izzet Sakalli

We introduce simulations aimed at assessing how well weak gravitational lensing of 21cm radiation from the Epoch of Reionization ($z \sim 8$) can be measured by an SKA-like radio telescope. A simulation pipeline has been implemented to…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-21 Alessandro Romeo , R. Benton Metcalf , Alkistis Pourtsidou

We describe J,H,K deep imaging of 90 arcmin fields around 4 QSOs and one Radio galaxy at redshifts in the range 0.06 to 0.30, and show their images, luminosity profiles, and NIR 2-colour diagrams of objects. We find that the QSO hosts are…

Astrophysics · Physics 2009-10-28 J. B. Hutchings , S. G. Neff

Gravitationally strongly lensed quasars (SL-QSO) offer invaluable insights into cosmological and astrophysical phenomena. With the data from ongoing and next-generation surveys, thousands of SL-QSO systems can be discovered expectedly,…

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