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We recently presented a new "artificial intelligence" method for the analysis of high-resolution absorption spectra (Bainbridge and Webb, Mon. Not. R. Astron. Soc. 2017, 468,1639-1670). This new method unifies three established numerical…

Instrumentation and Methods for Astrophysics · Physics 2017-05-01 Matthew B. Bainbridge , John K. Webb

Exploring the possibility that fundamental constants of Nature might vary temporally or spatially constitutes one of the key science drivers for the European Southern Observatory's ESPRESSO spectrograph on the VLT and for the HIRES…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-21 Chung-Chi Lee , John K. Webb , R. F. Carswell , Dinko Milaković

The high resolution spectrograph ESPRESSO on the VLT allows measurements of fundamental constants at unprecedented precision and hence enables tests for spacetime variations predicted by some theories. In a series of recent papers, we…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-08 Chung-Chi Lee , John K. Webb , Robert F. Carswell , Vladimir A. Dzuba , Victor V. Flambaum , Dinko Milaković

This article reviews the two major recent developments that significantly improved cosmological measurements of fundamental constants derived from high resolution quasar spectroscopy. The first one is the deployment of astronomical Laser…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-20 Dinko Milaković , Chung-Chi Lee , Paolo Molaro , John K. Webb

This paper describes the optimisation theory on which VPFIT, a non-linear least-squares program for modelling absorption spectra, is based. Particular attention is paid to precision. Voigt function derivatives have previously been…

Instrumentation and Methods for Astrophysics · Physics 2021-10-20 John K. Webb , Robert F. Carswell , Chung-Chi Lee

Hyperspectral Imaging comprises excessive data consequently leading to significant challenges for data processing, storage and transmission. Compressive Sensing has been used in the field of Hyperspectral Imaging as a technique to compress…

Computer Vision and Pattern Recognition · Computer Science 2024-01-29 Jon Alvarez Justo , Daniela Lupu , Milica Orlandic , Ion Necoara , Tor Arne Johansen

Development of fundamental physics relies on the constancy of various fundamental quantities such as the fine structure constant. Detecting or constraining the possible time variations of these fundamental physical quantities is an…

Astrophysics · Physics 2009-11-10 H. Chand , R. Srianand , P. Petitjean , B. Aracil

With the increasing penetration of high-frequency sensors across a number of biological and physical systems, the abundance of the resulting observations offers opportunities for higher statistical accuracy of down-stream estimates, but…

Optimization and Control · Mathematics 2020-11-06 Shushu Zhang , Vivak Patel

We assess the cosmological variability of the fine-structure constant from the analysis of an ensemble of Fe II absorption lines at the redshift z=1.15 toward the QSO HE 0515-4414 by means of the standard many-multiplet (MM) technique and…

Astrophysics · Physics 2009-11-10 Ralf Quast , Dieter Reimers , Sergei A. Levshakov

Very Long Baseline Interferometry (VLBI) provides the highest-resolution radio intensity maps, crucial for detailed studies of compact sources like active galactic nuclei (AGN) and their relativistic jets. Analyzing jet components in these…

Instrumentation and Methods for Astrophysics · Physics 2025-10-02 Alfredo Amador-Portes , Eva Palafox , Víctor M. Patiño-Álvarez , Vahram Chavushyan , Andrei P. Lobanov , Sergio A. Dzib

I present the Automated Line Fitting Algorithm, ALFA, a new code which can fit emission line spectra of arbitrary wavelength coverage and resolution, fully automatically. In contrast to traditional emission line fitting methods which…

Solar and Stellar Astrophysics · Physics 2016-01-20 Roger Wesson

Observations of metal absorption systems in the spectra of distant quasars allow to constrain a possible variation of the fine-structure constant throughout the history of the Universe. Such a test poses utmost demands on the wavelength…

Biomedical imaging is unequivocally dependent on the ability to reconstruct interpretable and high-quality images from acquired sensor data. This reconstruction process is pivotal across many applications, spanning from magnetic resonance…

Signal Processing · Electrical Eng. & Systems 2019-09-24 Ben Luijten , Regev Cohen , Frederik J. de Bruijn , Harold A. W. Schmeitz , Massimo Mischi , Yonina C. Eldar , Ruud J. G. van Sloun

We report unbiased AI measurements of the fine structure constant $\alpha$ in two proximate absorption regions in the spectrum of the quasar HE0515$-$4414. The data are high resolution, high signal to noise, and laser frequency comb…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-18 John K. Webb , Chung-Chi Lee , Dinko Milakovic , Victor V. Flambaum , Vladimir A. Dzuba , Joao Magueijo

A new method for examining the possible space-time variation of the fine structure constant ($\alpha$) is proposed. The technique uses a relatively simple measurement with an optical resonator to compare atom-stabilized optical frequency…

Atomic Physics · Physics 2007-05-23 J. R. Torgerson

Controlling the properties of organic/inorganic materials requires detailed knowledge of their molecular adsorption geometries. This is often unattainable, even with current state-of-the-art tools. Visualizing the structure of complex…

Detecting or placing upper limits on spacetime variations of fundamental constants requires quantifying every potential source of uncertainty. We continue our previous study into the impact of continuum variations on measurements of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-02 John K. Webb , Chung-Chi Lee , Dinko Milaković , Darren Dougan , Vladimir A. Dzuba , Victor V. Flambaum

This paper describes the application of a real coded genetic algorithm (GA) to align two or more 2-D images by means of image registration. The proposed search strategy is a transformation parameters-based approach involving the affine…

Neural and Evolutionary Computing · Computer Science 2012-04-11 Mosab Bazargani , António dos Anjos , Fernando G. Lobo , Ali Mollahosseini , Hamid Reza Shahbazkia

This article discusses the integration of the Artificial Bee Colony (ABC) algorithm with two supervised learning methods, namely Artificial Neural Networks (ANNs) and Adaptive Network-based Fuzzy Inference System (ANFIS), for feature…

Systems and Control · Electrical Eng. & Systems 2025-01-14 Amir Pouya Masoumi , Leo Creedon , Ramen Ghosh , Nimra Munir , Ross McMorrow , Marion McAfee

Conformal prediction has emerged as a popular technique for facilitating valid predictive inference across a spectrum of machine learning models, under minimal assumption of exchangeability. Recently, Hoff (2023) showed that full conformal…

Statistics Theory · Mathematics 2025-11-24 Pankaj Bhagwat , Linglong Kong , Bei Jiang
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