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Related papers: Unfolding X-ray Spectral Data: Conditions and Appl…

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This work is concerned with optical imaging in strongly diffusive environments. We consider a typical setting in optical coherence tomography where a sample is probed by a collection of wavefields produced by a laser and propagating through…

Optics · Physics 2024-12-10 Randy Bartels , Olivier Pinaud , Maxine Varughese

We have developed a general framework for modeling gyrosynchrotron and free-free emission from solar flaring loops and used it to test the premise that 2D maps of source parameters, particularly magnetic field, can be deduced from spatially…

Solar and Stellar Astrophysics · Physics 2015-06-15 Dale E. Gary , Gregory D. Fleishman , Gelu M. Nita

Flux-resolved X-ray spectroscopy is widely adopted to investigate the spectral variation of a target between various flux levels. In many cases it is done through horizontally splitting a single light curve into multiple flux levels with…

High Energy Astrophysical Phenomena · Physics 2023-01-03 Jia-Lai Kang , Jun-Xian Wang

We consider a random geometric graph with vertices sampled from a probability measure supported on $\mathbb R^d$, and study its connectivity. We show the graph is typically disconnected, unless the sampling density has superexponential…

Probability · Mathematics 2021-04-07 Henry-Louis de Kergorlay

The automatic classification of X-ray detections is a necessary step in extracting astrophysical information from compiled catalogs of astrophysical sources. Classification is useful for the study of individual objects, statistics for…

Instrumentation and Methods for Astrophysics · Physics 2024-01-30 Víctor Samuel Pérez-Díaz , Juan Rafael Martínez-Galarza , Alexander Caicedo , Raffaele D'Abrusco

Spectral 3D computer vision examines both the geometric and spectral properties of objects. It provides a deeper understanding of an object's physical properties by providing information from narrow bands in various regions of the…

Computer Vision and Pattern Recognition · Computer Science 2023-02-17 Yajie Sun , Ali Zia , Vivien Rolland , Charissa Yu , Jun Zhou

Accurate knowledge of the neutron energy spectra is useful in basic research and applications. The overall procedure of measuring and unfolding the fast neutron energy spectra with BC501A liquid scintillation detector is described. The…

Instrumentation and Detectors · Physics 2014-07-01 Yonghao Chen , Ximeng Chen , Jiarong Lei , Li An , Xiaodong Zhang , Jianxiong Shao , Pu Zheng , Xinhua Wang

Deconvolving ("unfolding'') detector distortions is a critical step in the comparison of cross section measurements with theoretical predictions in particle and nuclear physics. However, most existing approaches require histogram binning…

High Energy Physics - Phenomenology · Physics 2024-12-19 Krish Desai , Benjamin Nachman , Jesse Thaler

Gravitational lensing is proven to be one of the most efficient tools for studying the Universe. The spectral confirmation of such sources requires extensive calibration. This paper discusses the spectral extraction technique for the case…

Fibre-fed spectrographs now have throughputs equivalent to slit spectrographs. However, the sky subtraction accuracy that can be reached has often been pinpointed as one of the major issues associated with the use of fibres. Using technical…

With the increasing number of directly imaged giant exoplanets the current atmosphere models are often not capable of fully explaining the spectra and luminosity of the sources. A particularly challenging component of the atmosphere models…

Earth and Planetary Astrophysics · Physics 2015-06-11 Veselin B. Kostov , Dániel Apai

Using data from the XMM-Newton and INTEGRAL observatories, we have detected a cutoff at energies above 10 keV in the X-ray spectra of the ultraluminous X-ray sources HoIX X-1 and M82 X-1. The spectra obtained can be described by a model of…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Sergey Sazonov , Alexander Lutovinov , Roman Krivonos

Spectral methods have emerged as a simple yet surprisingly effective approach for extracting information from massive, noisy and incomplete data. In a nutshell, spectral methods refer to a collection of algorithms built upon the eigenvalues…

Machine Learning · Statistics 2021-10-26 Yuxin Chen , Yuejie Chi , Jianqing Fan , Cong Ma

A new method to calculate the spectrum using cascaded open systems and master equations is presented. The method uses two state analyzer atoms which are coupled to the system of interest, whose spectrum of radiation is read from the…

Quantum Physics · Physics 2015-06-26 Martti Havukainen , Stig Stenholm

We present a system of X-ray photometry for the Chandra satellite. X-ray photometry can be a powerful tool to obtain flux estimates, hardness ratios, and colors unbiased by assumptions about spectral shape and independent of temporal and…

Astrophysics · Physics 2008-12-18 H. -J. Grimm , J. McDowell , G. Fabbiano , M. Elvis

Resonant inelastic x-ray scattering (RIXS) has become a powerful tool in the study of the electronic structure of condensed matter. Although the linewidths of many RIXS features are narrow, the experimental broadening can often hamper the…

Strongly Correlated Electrons · Physics 2012-02-13 J. Laverock , A. R. H. Preston , D. Newby , K. E. Smith , S. B. Dugdale

When a coherent laser beam impinges on a random sample (e.g. a colloidal suspension), the scattered light exhibits characteristic speckles. If the temporal coherence of the light source is too short, then the speckles disappear, along with…

Optics · Physics 2011-12-13 D. Brogioli , D. Salerno , F. Croccolo , R. Ziano , F. Mantegazza

We lay the foundations for a new fast method to reconstruct the electron density in x-ray scanning applications using measurements in the dark field. This approach is applied to a type of machine configuration with fixed energy sensitive…

Numerical Analysis · Mathematics 2015-05-08 James Webber

The computation of scientific data can be very time consuming even if they are ultimately determined by a small number of parameters. The principle of compressed sampling suggests that we can achieve a considerable decrease in the…

Biological Physics · Physics 2015-03-20 J. Almeida , J. Prior , M. B. Plenio

In this paper we describe a self-contained method for performing the spectral-imaging deconvolution of X-ray data on clusters of galaxies observed by the ASCA satellite. Spatially-resolved spectral studies of data from this satellite…

Astrophysics · Physics 2009-10-31 D. A. White , D. Buote