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Related papers: A Pan-Spectral Method of Abundance Determination

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Using the semi-analytic method proposed by \citet{Esma91} we calculate the abundances of the light elements produced during primordial nucleosynthesis assuming that the gauge coupling constants of the fundamental interactions may vary. We…

Astrophysics · Physics 2008-11-26 Susana J. Landau , Mercedes E. Mosquera , Hector Vucetich

We describe a new algorithm to calculate the vibrational nuclear level density of an atomic nucleus. Fictitious perturbation operators that probe the response of the system are generated by drawing their matrix elements from some…

Nuclear Theory · Physics 2024-09-13 Antonio Bjelčić , Nicolas Schunck

Poyiadjis et al. (2011) show how particle methods can be used to estimate both the score and the observed information matrix for state space models. These methods either suffer from a computational cost that is quadratic in the number of…

Computation · Statistics 2015-09-07 Christopher Nemeth , Paul Fearnhead , Lyudmila Mihaylova

This article investigates the problem of estimating stellar atmospheric parameters from spectra. Feature extraction is a key procedure in estimating stellar parameters automatically. We propose a scheme for spectral feature extraction and…

Instrumentation and Methods for Astrophysics · Physics 2015-08-04 Tan Yang , Xiangru Li

Recently published empirical abundance maps, obtained through (Zeeman) Doppler mapping (ZDM), do not currently agree with the abundance structures predicted by means of numerical models of atomic diffusion in magnetic atmospheres of ApBp…

Solar and Stellar Astrophysics · Physics 2015-10-28 G. Alecian

We present a new method to retrieve molecular abundances and temperature profiles from exoplanet atmosphere photometry and spectroscopy. We run millions of 1D atmosphere models in order to cover the large range of allowed parameter space,…

Earth and Planetary Astrophysics · Physics 2014-11-20 N. Madhusudhan , S. Seager

The new generation of multi-PetaWatt laser facilities will allow tests of Strong Field QED, as well as provide an opportunity for novel photon and lepton sources. The first experiments are planned to study the (nearly) head-on scattering of…

Plasma Physics · Physics 2024-02-27 Óscar Amaro , Marija Vranic

The Sun has been found to be depleted in refractory (rock-forming) elements relative to nearby solar analogs, suggesting a potential indicator of planet formation. Given the small amplitude of the depletion, previous analyses have primarily…

Solar and Stellar Astrophysics · Physics 2021-02-10 Jacob Nibauer , Eric J. Baxter , Bhuvnesh Jain , Jennifer L. van Saders , Rachael L. Beaton , Johanna K. Teske

We present and implement a probabilistic (Bayesian) method for producing catalogs from images of stellar fields. The method is capable of inferring the number of sources N in the image and can also handle the challenges introduced by noise,…

Instrumentation and Methods for Astrophysics · Physics 2015-06-12 Brendon J. Brewer , Daniel Foreman-Mackey , David W. Hogg

This paper presents a novel methodology for generating realistic abundance maps from hyperspectral imagery using an unsupervised, deep-learning-driven approach. Our framework integrates blind linear hyperspectral unmixing with…

Computer Vision and Pattern Recognition · Computer Science 2025-06-17 Martina Pastorino , Michael Alibani , Nicola Acito , Gabriele Moser

We develop a novel method to separate the components of a diffuse emission process based on an association with the energy spectra. Most of the existing methods use some information about the spatial distribution of components, e.g.,…

Instrumentation and Methods for Astrophysics · Physics 2012-02-07 Dmitry Malyshev

In an attempt to remove the systematic errors which have plagued the calibration of the HII region abundance sequence, we have theoretically modeled the extragalactic HII region sequence. We then used the theoretical spectra so generated in…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Angel R. Lopez-Sanchez , M. A. Dopita , L. J. Kewley , H. J. Zahid , D. C. Nicholls , J. Scharwachter

With the advent of large spectroscopic surveys the amount of high quality chemo-dynamical data in the Milky Way (MW) increased tremendously. Accurately and correctly capturing and explaining the detailed features in the high-quality…

Variational ab-initio methods in quantum chemistry stand out among other methods in providing direct access to the wave function. This allows in principle straightforward extraction of any other observable of interest, besides the energy,…

We apply the method of spectral sequences to study classical problems in analysis. We illustrate the method by finding polynomial vector fields that commute with a given polynomial vector field and finding integrals of polynomial…

Algebraic Topology · Mathematics 2024-02-07 Larry Bates , Martin Bendersky , Richard Churchill

While Spectral Methods have long been used for Principal Component Analysis, this survey focusses on work over the last 15 years with three salient features: (i) Spectral methods are useful not only for numerical problems, but also discrete…

Data Structures and Algorithms · Computer Science 2010-04-09 Ravindran Kannan

Consistency-based methods have emerged as an effective approach to uncertainty quantification (UQ) in large language models. These methods typically rely on several generations obtained via multinomial sampling, measuring their agreement…

This paper presents a semi-supervised hyperspectral unmixing solution that integrate the spatial information in the abundance estimation procedure. The proposed method is applied on a nonlinear model based on polynomial postnonlinear mixing…

Signal Processing · Electrical Eng. & Systems 2018-03-05 Fahime Amiri , Mohammad Hossein. Kahaei

The study of chemical abundances in stars with planets is an important ingredient for the models of formation and evolution of planetary systems. In order to determine accurate abundances, it is crucial to have a reliable set of atmospheric…

Solar and Stellar Astrophysics · Physics 2010-11-05 L. Ghezzi , K. Cunha , F. X. de Araújo , V. V. Smith , S. Schuler , R. de la Reza

The atmospheric abundances of elements provide essential insights into the formation and evolution history of stars. The visible wavelength window has been used almost exclusively in the past to determine the abundances of chemical elements…

Solar and Stellar Astrophysics · Physics 2016-12-21 S. S. Golriz , J. D. Landstreet
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