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Inadequacies in the knowledge of the primary beam response of current interferometric arrays often form a limitation to the image fidelity. We hope to overcome these limitations by constructing a frequency-resolved, full-polarization…

Astrophysics · Physics 2009-11-13 Attila Popping , Robert Braun

Data-driven models of stellar spectra are useful tools to study non-stellar information, such as the Diffuse Interstellar Bands (DIBs) caused by intervening interstellar material. Using $\sim 55000$ spectra of $\sim 17000$ red clump stars…

Astrophysics of Galaxies · Physics 2024-02-08 Kevin A. McKinnon , Melissa K. Ness , Constance M. Rockosi , Puragra Guhathakurta

Stereoscopic spectral imaging is an observing technique that affords rapid acquisition of limited spectral information over an entire image plane simultaneously. Light from a telescope is dispersed into multiple spectral orders, which are…

Astrophysics · Physics 2007-05-23 Craig E. DeForest , Charles C. Kankelborg

Future optical interferometric instrumentation mainly relies on the availability of an efficient cophasing system: once available, what has so far postponed the relevance of direct imaging with an interferometer will vanish. This paper…

Astrophysics · Physics 2008-11-26 O. Lardiere , F. Martinache , F. Patru

The point-spread function (PSF) is a fundamental property of any astronomical instrument. In interferometers, differing array configurations combined with their $uv$ coverage, and various weighting schemes can produce an irregular but…

Instrumentation and Methods for Astrophysics · Physics 2023-10-20 Jack F. Radcliffe , R. J. Beswick , A. P. Thomson , A. Njeri , T. W. B. Muxlow

Differential Chromatic Refraction (DCR) is caused by the wavelength dependence of our atmosphere's refractive index, which shifts the apparent positions of stars and galaxies and distorts their shapes depending on their spectral energy…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-24 Jaemyoung Jason Lee , Masao Sako , Richard Kessler , Alex I. Malz , The LSST Dark Energy Science Collaboration

In radio astronomy obtaining a high dynamic range in synthesis imaging of wide fields requires a correction for time and direction-dependent effects. Applying direction-dependent correction can be done by either partitioning the image in…

Instrumentation and Methods for Astrophysics · Physics 2019-09-17 Sebastiaan van der Tol , Bram Veenboer , André R. Offringa

Imaging through dynamic scattering media, such as biological tissue, presents a fundamental challenge due to light scattering and the formation of speckle patterns. These patterns not only degrade image quality but also decorrelate rapidly,…

We investigate the prospects for constraining the maximum scale of clumping in composition that is consistent with observed Type Ia supernova flux spectra. Synthetic spectra generated without purely spherical composition symmetry indicate…

Astrophysics · Physics 2009-11-06 R. C. Thomas , Daniel Kasen , David Branch , E. Baron

The digital revolution is transforming astronomy from a data-starved to a data-submerged science. Instruments such as the Atacama Large Millimeter Array (ALMA), the Large Synoptic Survey Telescope (LSST), and the Square Kilometer Array…

Instrumentation and Methods for Astrophysics · Physics 2012-09-25 Melvyn Wright

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

From natural guide star adaptive optics data taken with the Come-On Plus and with the Starfire Optical Range Generation II instruments in the JHK bands and in the I band respectively, we describe and analyse the point spread function. The…

Astrophysics · Physics 2015-06-24 Eric Tessier

Intensity interferometry is a well known method in astronomy. Recently, a related method called incoherent diffractive imaging (IDI) was proposed to apply intensity correlations of x-ray fluorescence radiation to determine the 3D…

Optics · Physics 2020-08-27 Fabian Trost , Kartik Ayyer , Henry Chapman

Optical interference is not only a fundamental phenomenon that has enabled new theories of light to be derived but it has also been used in interferometry for the measurement of small displacements, refractive index changes and surface…

Optics · Physics 2021-10-28 Chen Yang , Zhi-Yuan Zhou , Yan Li , Shi-Kai Liu , Zheng Ge , Guang-Can Guo , Bao-Sen Shi

Instruments for radio astronomical observations have come a long way. While the first telescopes were based on very large dishes and 2-antenna interferometers, current instruments consist of dozens of steerable dishes, whereas future…

Instrumentation and Methods for Astrophysics · Physics 2015-03-13 Stefan J. Wijnholds , Sebastiaan van der Tol , Ronald Nijboer , Alle-Jan van der Veen

High-dynamic-range (HDR) imaging is crucial for many computer graphics and vision applications. Yet, acquiring HDR images with a single shot remains a challenging problem. Whereas modern deep learning approaches are successful at…

Image and Video Processing · Electrical Eng. & Systems 2019-08-05 Christopher A. Metzler , Hayato Ikoma , Yifan Peng , Gordon Wetzstein

Radio interferometric imaging aims to estimate an unknown sky intensity image from degraded observations, acquired through an antenna array. In the theoretical case of a perfectly calibrated array, it has been shown that solving the…

Instrumentation and Methods for Astrophysics · Physics 2017-07-25 Audrey Repetti , Jasleen Birdi , Arwa Dabbech , Yves Wiaux

A long-held vision has been to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, and reveal interacting gas flows in binary systems. An…

Instrumentation and Methods for Astrophysics · Physics 2015-08-12 Dainis Dravins , Tiphaine Lagadec , Paul D. Nuñez

The observed interstellar scintillation pattern of an intra-day variable radio source is influenced by its source structure. If the velocity of the interstellar medium responsible for the scattering is comparable to the earth's, the vector…

Astrophysics · Physics 2009-11-07 J-P Macquart , D. L. Jauncey

The Earth's ionosphere refracts radio waves incident on an interferometer, resulting in shifts to the measured positions of radio sources. We present a method to smoothly remove these shifts and restore sources to their reference positions,…

Instrumentation and Methods for Astrophysics · Physics 2018-08-27 N. Hurley-Walker , P. J. Hancock