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Phase referencing is a standard calibration procedure in radio interferometry. It allows to detect weak sources by using quasi-simultaneous observations of closeby sources acting as calibrators. Therefore, it is assumed that, for each…

Instrumentation and Methods for Astrophysics · Physics 2011-01-25 I. Marti-Vidal , J. C. Guirado , S. Jimenez-Monferrer , J. M. Marcaide

Differential Dynamic Microscopy (DDM) analyzes traditional real-space microscope images to extract information on sample dynamics in a way akin to light scattering, by decomposing each image in a sequence into Fourier modes, and evaluating…

Soft Condensed Matter · Physics 2017-11-10 Fabio Giavazzi , Paolo Edera , Peter J. Lu , Roberto Cerbino

Radio interferometers designed to probe the 21cm signal from Cosmic Dawn and the Epoch of Reionisation must contend with systematic effects that make it difficult to achieve sufficient dynamic range to separate the 21cm signal from…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-24 Fraser Kennedy , Philip Bull , Michael Wilensky , Jacob Burba , Samir Choudhuri

Hyperspectral imaging has become a significant source of valuable data for astronomers over the past decades. Current instrumental and observing time constraints allow direct acquisition of multispectral images, with high spatial but low…

Computer Vision and Pattern Recognition · Computer Science 2019-12-30 Claire Guilloteau , Thomas Oberlin , Olivier Berné , Nicolas Dobigeon

Accurate alignment of the radio and optical celestial reference frames requires detailed understanding of physical factors that may cause offsets between the positions of the same object measured in different spectral bands. Opacity in…

Astrophysics · Physics 2008-07-21 Y. Y. Kovalev , A. P. Lobanov , A. B. Pushkarev , J. A. Zensus

Simulated images are essential in algorithm development and instrument testing for optical telescopes. During real observations, images obtained by optical telescopes are affected by spatially variable point spread functions (PSFs), a…

Instrumentation and Methods for Astrophysics · Physics 2025-02-17 Zeyu Bai , Peng Jia , Jiameng Lv , Xiang Zhang , Wennan Xiang , Lin Nie

The impulsive noise in astronomical images originates from various sources. It develops as a result of thermal generation in pixels, collision of cosmic rays with image sensor or may be induced by high readout voltage in Electron…

Instrumentation and Methods for Astrophysics · Physics 2016-09-28 A. Popowicz , A. R. Kurek , T. Blachowicz , V. Orlov , B. Smolka

Through an extensive set of realistic synthetic observations (produced in Paper I), we assess in this part of the paper series (Paper III) how the choice of observational techniques affects the measurement of star-formation rates (SFRs) in…

Solar and Stellar Astrophysics · Physics 2017-11-01 Christine M. Koepferl , Thomas P. Robitaille , James E. Dale

Long baseline diffraction-limited optical aperture synthesis technology by interferometry plays an important role in scientific study and practical application. In contrast to amplitude (phase) interferometry, intensity interferometry --…

While conventional imaging in VLBI provides information only about the relative position between different features of a given source, phase-referenced observations can provide precise positional information with respect to an external…

Astrophysics · Physics 2007-05-23 Eduardo Ros

High-fidelity spectroscopy presents challenges for both observations and in designing instruments. High-resolution and high-accuracy spectra are required for verifying hydrodynamic stellar atmospheres and for resolving intergalactic…

Instrumentation and Methods for Astrophysics · Physics 2015-05-18 Dainis Dravins

In coherent X-ray diffraction microscopy the diffraction pattern generated by a sample illuminated with coherent x-rays is recorded, and a computer algorithm recovers the unmeasured phases to synthesize an image. By avoiding the use of a…

Doppler Imaging produces 2D global maps of rotating objects using high-dispersion spectroscopy. When applied to brown dwarfs and extrasolar planets, this technique can constrain global atmospheric dynamics and/or magnetic effects on these…

Solar and Stellar Astrophysics · Physics 2014-07-02 Ian J. M. Crossfield

The atmospheric scintillation of stars is the main limitation of the accuracy of ground-based photometry of astronomical objects. This becomes particularly noticeable for a study of a variability with amplitudes on the order to thousandths…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Victor Kornilov

Images obtained with single-conjugate adaptive optics (AO) show spatial variation of the point spread function (PSF) due to both atmospheric anisoplanatism and instrumental aberrations. The poor knowledge of the PSF across the field of view…

Aperture synthesis instruments providing a generally highly uniform sampling of the visibility function often leave an unsampled hole near the origin of the (u,v)-plane. In this paper, originally published in 1979, we first describe the…

Instrumentation and Methods for Astrophysics · Physics 2017-11-29 R. D. Ekers , A. H. Rots

Dark photons can be the ultralight dark matter candidate, interacting with Standard Model particles via kinetic mixing. We propose to search for ultralight dark photon dark matter (DPDM) through the local absorption at different radio…

High Energy Physics - Phenomenology · Physics 2023-05-12 Haipeng An , Shuailiang Ge , Wen-Qing Guo , Xiaoyuan Huang , Jia Liu , Zhiyao Lu

Anisoplanatic effects can cause significant systematic photometric uncertainty in the analysis of dense stellar fields observed with adaptive optics. Program packages have been developed for a spatially variable PSF, but they require that a…

Instrumentation and Methods for Astrophysics · Physics 2009-12-08 R. Schoedel

The demand for higher data rates and better synchronization in communication and navigation systems necessitates the development of new wideband and tunable sources with noise performance exceeding that provided by traditional oscillators…

High dynamic range (HDR) imaging is of fundamental importance in modern digital photography pipelines and used to produce a high-quality photograph with well exposed regions despite varying illumination across the image. This is typically…

Image and Video Processing · Electrical Eng. & Systems 2024-07-24 Sibi Catley-Chandar , Thomas Tanay , Lucas Vandroux , Aleš Leonardis , Gregory Slabaugh , Eduardo Pérez-Pellitero