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It is shown that the basic observed properties of the gamma-ray bursts (GRBs) are accounted for if one assumes that the GRBs arise by blueshifting the emission radiation of hydrogen and helium generated during the last scattering epoch. The…

General Relativity and Quantum Cosmology · Physics 2016-02-24 Andrzej Krasiński

We present a method for subtracting point sources from interferometric radio images via forward modeling of the instrument response and involving an algebraic nonlinear minimization. The method is applied to simulated maps of the Murchison…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 G. Bernardi , D. A. Mitchell , S. M. Ord , L. J. Greenhill , B. Pindor , R. B. Wayth , J. S. B. Wyithe

Gravitational-wave (GW) events are generally believed to originate in galaxies and can thus serve, like galaxies, as tracers of the universe's large-scale structure. In GW observations, waveform analysis provides direct measurements of…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-16 Ya-Nan Du , Ji-Yu Song , Yichao Li , Shang-Jie Jin , Ling-Feng Wang , Jing-Fei Zhang , Xin Zhang

A radio interferometer indirectly measures the intensity distribution of the sky over the celestial sphere. Since measurements are made over an irregularly sampled Fourier plane, synthesising an intensity image from interferometric…

Instrumentation and Methods for Astrophysics · Physics 2014-03-18 Daniel Muscat

Fourier transform scanning tunneling spectroscopy (FT-STS), or quasiparticle interference (QPI), has become an influential tool for the study of a wide range of important materials in condensed matter physics. However, FT-STS in complex…

Mesoscale and Nanoscale Physics · Physics 2016-09-21 A J Macdonald , Y-S Tremblay-Johnston , S Grothe , S Chi , P Dosanjh , S Johnston , S A Burke

The advent of a new generation of low frequency interferometers has opened a direct window into the Epoch of Reionisation (EoR). However, key to a detection of the faint 21-cm signal, and reaching the sensitivity limits of these arrays, is…

Instrumentation and Methods for Astrophysics · Physics 2018-12-05 Ronniy C. Joseph , Cathryn M. Trott , Randall B. Wayth

Most brown dwarfs have atmospheres with temperatures cold enough to form clouds. A variety of materials likely condense, including refractory metal oxides and silicates; the precise compositions and crystal structures of predicted cloud…

Solar and Stellar Astrophysics · Physics 2021-11-03 Jessica L. Luna , Caroline V. Morley

Continuous gravitational-wave signals (CWs) are long-lasting quasi-monochromatic gravitational-wave signals expected to be emitted by rapidly-rotating non-axisymmetric neutron stars. Depending on the rotational frequency and sky location of…

General Relativity and Quantum Cosmology · Physics 2024-03-06 Rafel Jaume , Rodrigo Tenorio , Alicia M. Sintes

Radio interferometers are phased arrays producing high-resolution images from the covariance matrix of measurements. Calibration of such instruments is necessary and is a critical task. This is how the estimation of instrumental errors is…

Instrumentation and Methods for Astrophysics · Physics 2023-09-26 Yassine Mhiri , Mohammed Nabil El Korso , Arnaud Breloy , Pascal Larzabal

Ghost imaging (GI) is an intriguing imaging technology which achieves the object images through intensity correlation between reference patterns and bucket signal. Here, we propose a probability model to explain the imaging mechanism of…

Image and Video Processing · Electrical Eng. & Systems 2020-12-04 Wen-Kai Yu , Jian Leng

Galaxy clusters grow by a sequence of mergers with other clusters and galaxy groups. During these mergers, shocks and/or turbulence are created within the intracluster medium (ICM). In this process, particles could be accelerated to highly…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 R. J. van Weeren , H. J. A. Rottgering , M. Bruggen

We present a fitting function to describe the statistics of flux modulations caused by interstellar scintillation. The function models a very general quantity: the cross-correlation of the flux observed from a compact radio source of finite…

Astrophysics · Physics 2009-11-13 J. Goodman , R. Narayan

spectral-based subspace learning is a common data preprocessing step in many machine learning pipelines. The main aim is to learn a meaningful low dimensional embedding of the data. However, most subspace learning methods do not take into…

Machine Learning · Computer Science 2023-06-14 Firas Laakom , Jenni Raitoharju , Nikolaos Passalis , Alexandros Iosifidis , Moncef Gabbouj

Recently, both theoretical arguments and observational evidence suggested that a small fraction of fast radio bursts (FRBs) could be associated with gamma-ray bursts (GRBs). If such FRB/GRB association systems are commonly detected in the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 He Gao , Zhuo Li , Bing Zhang

Direction dependent calibration of widefield radio interferometers estimates the systematic errors along multiple directions in the sky. This is necessary because with most systematic errors that are caused by effects such as the ionosphere…

Instrumentation and Methods for Astrophysics · Physics 2021-12-22 Sarod Yatawatta

A new list of physical characteristics of 4261 astrometric radio sources, including all 717 ICRF-Ext.2 sources has been compiled. Comparison of our data of optical characteristics with the official International Earth Rotation and Reference…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Oleg Titov , Zinovy Malkin

We describe and demonstrate a technique for correcting direction dependent artifacts due to asymmetries in antenna patterns and differences among antennas used in radio interoferometric imaging. The technique can correct images in all…

Instrumentation and Methods for Astrophysics · Physics 2021-10-13 W. D. Cotton , T. Mauch

High-fidelity simulated astronomical images are an important tool in developing and measuring the performance of image-processing algorithms, particularly for high precision measurements of cosmic shear -- correlated distortions of images…

Instrumentation and Methods for Astrophysics · Physics 2024-03-25 Claire-Alice Hébert , Joshua E. Meyers , My H. Do , Patricia R. Burchat , the LSST Dark Energy Science Collaboration

We demonstrate experimentally ghost optical coherence tomography using a broadband incoherent supercontinuum light source with shot-to-shot random spectral fluctuations. The technique is based on ghost imaging in the spectral domain where…

Understanding and dealing with inference biases in gravitational-wave (GW) parameter estimation when a plethora of signals are present in the data is one of the key challenges for the analysis of data from future GW detectors. Working…

General Relativity and Quantum Cosmology · Physics 2021-08-25 Andrea Antonelli , Ollie Burke , Jonathan R. Gair
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