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A new multi-frequency synthesis algorithm for reconstructing images from multi-frequency VLBI data is proposed. The algorithm is based on a generalized maximum-entropy method, and makes it possible to derive an effective spectral correction…

Astrophysics · Physics 2011-08-31 Anisa T. Bajkova

To improve the precision of inferences and reduce costs there is considerable interest in combining data from several sources such as sample surveys and administrative data. Appropriate methodology is required to ensure satisfactory…

Methodology · Statistics 2022-10-21 Dexter Cahoy , Joseph Sedransk

This work deals with an inverse source problem for the biharmonic wave equation. A two-stage numerical method is proposed to identify the unknown source from the multi-frequency phaseless data. In the first stage, we introduce some…

Numerical Analysis · Mathematics 2024-01-08 Yan Chang , Yukun Guo , Yue Zhao

Although interesting in themselves, extragalactic sources emitting in the microwave range (mainly radio-loud active galactic nuclei and dusty galaxies) are also considered a contaminant from the point of view of Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-31 P. Diego-Palazuelos , P. Vielva , D. Herranz

We describe a method to construct continuum spectra for radio sources on the basis of entries from various source catalogues in comparatively large error boxes around a given sky position. Sources from the UTR-2 catalogue (Braude et al.…

Astrophysics · Physics 2007-05-23 O. V. Verkhodanov , H. Andernach , N. V. Verkhodanova

Radio astronomical observations have very poor signal to noise ratios, unlike in other disciplines. On the other hand, it is possible to observe the object of interest for long time intervals as well as using a wider bandwidth.…

Astrophysics · Physics 2008-09-02 Sarod Yatawatta

This paper investigates the inverse source problem with a single propagating mode at multiple frequencies in an acoustic waveguide. The goal is to provide both theoretical justifications and efficient algorithms for imaging extended sources…

Numerical Analysis · Mathematics 2023-02-24 Shixu Meng

We consider periodic single-photon sources with combined multiplexing in which the outputs of several time-multiplexed sources are spatially multiplexed. We give a full statistical description of such systems in order to optimize them with…

Quantum Physics · Physics 2016-10-05 Ferenc Bodog , Peter Adam , Matyas Mechler , Imre Santa , Matyas Koniorczyk

We propose a new, simple, dedicated X-ray mission to measure the power spectrum of density fluctuations in the Universe, by accurately mapping the X-ray background on the whole sky on scales of arounf one sq deg. Since the method relies on…

Astrophysics · Physics 2015-06-24 X. Barcons , A. C. Fabian

This paper presents B-CLEAN-SC, a variation of CLEAN-SC for broadband sources. Opposed to CLEAN-SC, which ``deconvolves'' the beamforming map for each frequency individually, B-CLEAN-SC processes frequency intervals. Instead of performing a…

Sound · Computer Science 2023-08-21 Armin Goudarzi

Point source detection techniques are used to identify and localise point sources in radio astronomical surveys. With the development of the Square Kilometre Array (SKA) telescope, survey images will see a massive increase in size from…

Computer Vision and Pattern Recognition · Computer Science 2022-02-09 Duncan Tilley , Christopher W. Cleghorn , Kshitij Thorat , Roger Deane

It has been shown lately the optimality of uncoded transmission in estimating Gaussian sources over homogeneous/symmetric Gaussian multiple access channels (MAC) using multiple sensors. It remains, however, unclear whether it still holds…

Information Theory · Computer Science 2007-09-27 Shuangqing Wei , Rajgopal Kannan , Sitharama Iyengar , Nageswara S. Rao

This paper considers filters (the Mexican hat wavelet, the matched and the scale-adaptive filters) that optimize the detection/separation of point sources on a background. We make a one-dimensional treatment, we assume that the sources have…

Astrophysics · Physics 2009-11-07 R. B. Barreiro , J. L. Sanz , D. Herranz , E. Martinez-Gonzalez

Cross-matching catalogues from radio surveys to catalogues of sources at other wavelengths is extremely hard, because radio sources are often extended, often consist of several spatially separated components, and often no radio component is…

Instrumentation and Methods for Astrophysics · Physics 2020-08-13 Dongwei Fan , Tamás Budavári , Ray P. Norris , Amitabh Basu

(Abridged) We present a new method for detecting and measuring compact sources in conditions of intense, and highly variable, fore/background. While all most commonly used packages carry out the source detection over the signal image, our…

In this paper, we address the problem of recovering point sources from two dimensional low-pass measurements, which is known as super-resolution problem. This is the fundamental concern of many applications such as electronic imaging,…

Information Theory · Computer Science 2019-05-17 Iman Valiulahi , Sajad Daei , Farzan Haddadi , Farzad Parvaresh

Modern radio interferometers deliver large volumes of data containing high-sensitivity sky maps over wide fields-of-view. These large area observations can contain various and superposed structures such as point sources, extended objects,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-05 Richard Fuchs , Jakob Knollmüller , Jakob Roth , Vincent Eberle , Philipp Frank , Torsten A. Enßlin , Lukas Heinrich

We present a framework for the optimal filtering of spherical signals contaminated by realizations of an additive, zero-mean, uncorrelated and anisotropic noise process on the sphere. Filtering is performed in the wavelet domain given by…

Signal Processing · Electrical Eng. & Systems 2021-02-09 Adeem Aslam , Zubair Khalid , Jason D. McEwen

In the first TABASCAL paper we showed how to calibrate in the presence of Radio Frequency Interference (RFI) sources by simultaneously isolating the trajectories and signals of the RFI sources. Here we show that we can accurately remove RFI…

Instrumentation and Methods for Astrophysics · Physics 2025-10-01 Chris Finlay , Bruce A. Bassett , Martin Kunz , Nadeem Oozeer

It is the aim of this paper to introduce the use of isotropic wavelets to detect and determine the flux of point sources appearing in CMB maps. The most suited wavelet to detect point sources filtered with a Gaussian beam is the Mexican…