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Analyses of stellar spectra often begin with the determination of a number of parameters that define a model atmosphere. This work presents a prototype for an automated spectral classification system that uses a 15 nm-wide region around…

Astrophysics · Physics 2016-08-30 C. Allende Prieto

We derive, similar to Lau and Riha, a matrix formulation of a general best approximation theorem of Singer for the special case of spectral approximations of a given matrix from a given subspace. Using our matrix formulation we describe the…

Numerical Analysis · Mathematics 2025-06-12 Vance Faber , Jörg Liesen , Petr Tichý

We consider the problem of parameter estimation in a high-dimensional generalized linear model. Spectral methods obtained via the principal eigenvector of a suitable data-dependent matrix provide a simple yet surprisingly effective…

Statistics Theory · Mathematics 2025-07-11 Yihan Zhang , Hong Chang Ji , Ramji Venkataramanan , Marco Mondelli

The stellar population synthesis in unresolved composite objects is a very tricky problem. Indeed, it is a degenerate problem since many parameters affect the observables. The stellar population synthesis issue thus deserves a deep and…

Astrophysics · Physics 2009-11-10 J. Moultaka

In a mixed generalized linear model, the goal is to learn multiple signals from unlabeled observations: each sample comes from exactly one signal, but it is not known which one. We consider the prototypical problem of estimating two…

Statistics Theory · Mathematics 2026-01-12 Yihan Zhang , Marco Mondelli , Ramji Venkataramanan

In this work, we select the high signal-to-noise ratio spectra of stars from the LAMOST data andmap theirMK classes to the spectral features. The equivalentwidths of the prominent spectral lines, playing the similar role as the multi-color…

Solar and Stellar Astrophysics · Physics 2015-05-25 Chao Liu , Wen-Yuan Cui , Bo Zhang , Jun-Chen Wan , Li-Cai Deng , Yonghui Hou , Yuefei Wang , Ming Yang , Yong Zhang

We devised a straightforward procedure to derive the atmosphere fundamental parameters of stars across the different MK spectral types by comparing mid-resolution spectroscopic observations with theoretical grids of synthetic spectra.The…

Astrophysics · Physics 2007-05-23 E. Bertone , A. Buzzoni

This paper deals with subsampled spectral gradient methods for minimizing finite sum. Subsample function and gradient approximations are employed in order to reduce the overall computational cost of the classical spectral gradient methods.…

Numerical Analysis · Mathematics 2019-11-04 Stefania Bellavia , Nataša Krklec Jerinkić , Greta Malaspina

Stellar space density analyses, once a very active area of astronomical research, involved transforming counts of stars to given limiting magnitudes in selected areas of the sky into graphs of the number of stars per cubic parsec as a…

Astrophysics of Galaxies · Physics 2020-06-19 B. Cameron Reed

Super-resolution theory aims to estimate the discrete components lying in a continuous space that constitute a sparse signal with optimal precision. This work investigates the potential of recent super-resolution techniques for spectral…

Information Theory · Computer Science 2016-11-24 M. Ferreira Da Costa , W. Dai

The purpose of this letter is to compare the quality of different methods for estimating stellar masses of galaxies. We compare the results of (a) fitting stellar population synthesis models to broad band colors from SDSS and 2MASS, (b) the…

Astrophysics · Physics 2009-11-10 N. Drory , R. Bender , U. Hopp

We study spectral measures generated by infinite convolution products of discrete measures generated by Hadamard triples, and we present sufficient conditions for the measures to be spectral, generalizing a criterion by Strichartz. We then…

Functional Analysis · Mathematics 2015-09-16 Dorin Ervin Dutkay , Chun-Kit Lai

We describe a novel method for blind, single-image spectral super-resolution. While conventional super-resolution aims to increase the spatial resolution of an input image, our goal is to spectrally enhance the input, i.e., generate an…

Computer Vision and Pattern Recognition · Computer Science 2017-03-29 Silvano Galliani , Charis Lanaras , Dimitrios Marmanis , Emmanuel Baltsavias , Konrad Schindler

We present a unified framework to derive fundamental stellar parameters by combining all available observational and theoretical information for a star. The algorithm relies on the method of Bayesian inference, which for the first time…

Solar and Stellar Astrophysics · Physics 2015-06-18 Ralph Schönrich , Maria Bergemann

We introduce a novel method for discerning optical telescope images of stars from those of galaxies using Gaussian processes (GPs). Although applications of GPs often struggle in high-dimensional data modalities such as optical image…

Instrumentation and Methods for Astrophysics · Physics 2022-03-14 Amanda L. Muyskens , Imène R. Goumiri , Benjamin W. Priest , Michael D. Schneider , Robert E. Armstrong , Jason M. Bernstein , Ryan Dana

We have observed 28 local galaxies in the wavelength range between 1 and 2.4 mic in order to define template spectra of the normal galaxies along the Hubble sequence. Five galaxies per morphological type were observed in most cases, and the…

Astrophysics · Physics 2010-04-06 F. Mannucci , F. Basile , B. M. Poggianti , A. Cimatti , E. Daddi , L. Pozzetti , L. Vanzi

A number of problems in computer vision and related fields would be mitigated if camera spectral sensitivities were known. As consumer cameras are not designed for high-precision visual tasks, manufacturers do not disclose spectral…

Image and Video Processing · Electrical Eng. & Systems 2023-07-13 Grigory Solomatov , Derya Akkaynak

Nonlinear spectral problems arise across a range of fields, including mechanical vibrations, fluid-solid interactions, and photonic crystals. Discretizing infinite-dimensional nonlinear spectral problems often introduces significant…

Numerical Analysis · Mathematics 2025-04-25 Matthew J. Colbrook , Catherine Drysdale

This proceeding is intended to be a first introduction to spectral methods. It is written around some simple problems that are solved explicitly and in details and that aim at demonstrating the power of those methods. The mathematical…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Philippe Grandclement

We describe an accurate new method for determining absolute magnitudes, and hence also K-corrections, which is simpler than most previous methods, being based on a quadratic function of just one suitably chosen observed color. The method…

Astrophysics of Galaxies · Physics 2015-06-23 Richard Beare , Michael Brown , Kevin Pimbblet