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The convectively driven, weakly magnetized regions of the solar photosphere dominate the Sun's surface at any given time, but the temporal variations of these quiet regions of the photosphere throughout the solar cycle are still not well…

Solar and Stellar Astrophysics · Physics 2025-05-05 James Crowley , Ivan Milic , Gianna Cauzzi , Kevin Reardon

X-rays and gamma-rays from astronomical sources such as solar flares are mostly absorbed by the Earth's atmosphere. Resulting electron-ion production rate as a function of height depends on the intensity and wavelength of the injected…

Earth and Planetary Astrophysics · Physics 2016-04-27 Sourav Palit , Suman Ray , Sandip K. Chakrabarti

Radio astronomy is currently thriving with new large ground-based radio telescopes coming online in preparation for the upcoming Square Kilometre Array (SKA). Facilities like LOFAR, MeerKAT/SKA, ASKAP/SKA, and the future SKA-LOW bring…

Instrumentation and Methods for Astrophysics · Physics 2023-08-02 Benjamin Naoto Chiche , Julien N. Girard , Joana Frontera-Pons , Arnaud Woiselle , Jean-Luc Starck

We introduce a new framework for point-spread function (PSF) subtraction based on the spatio-temporal variation of speckle noise in high-contrast imaging data where the sampling timescale is faster than the speckle evolution timescale. One…

Instrumentation and Methods for Astrophysics · Physics 2023-01-23 Briley L. Lewis , Michael P. Fitzgerald , Rupert H. Dodkins , Kristina K. Davis , Jonathan Lin

We present a Bayesian analysis of data from the FIELDS instrument on board the Parker Solar Probe (PSP) spacecraft with the aim of constraining low frequency ($\lesssim$ 6 MHz) sky in preparation for several upcoming lunar-based…

Astrophysics of Galaxies · Physics 2023-03-29 Neil Bassett , David Rapetti , Bang D. Nhan , Brent Page , Jack O. Burns , Marc Pulupa , Stuart D. Bale

We study image formation with the solar gravitational lens (SGL). We consider a point source that is positioned at a large but finite distance from the Sun. We assume that an optical telescope is positioned in the image plane, in the focal…

General Relativity and Quantum Cosmology · Physics 2020-02-25 Slava G. Turyshev , Viktor T. Toth

In multi-photon microscopy (MPM), a recent in-vivo fluorescence microscopy system, the task of image restoration can be decomposed into two interlinked inverse problems: firstly, the characterization of the Point Spread Function (PSF) and…

Image and Video Processing · Electrical Eng. & Systems 2024-11-08 Julien Ajdenbaum , Emilie Chouzenoux , Claire Lefort , Ségolène Martin , Jean-Christophe Pesquet

The calibration of ground-based submillimetre observations has always been a difficult process. We discuss how to overcome the limitations imposed by the submillimetre atmosphere. Novel ways to improve line-of-sight opacity estimates are…

Three-dimensional magnetohydrodynamic simulations of the surface layers of the Sun intrinsically produce a predominantly horizontal magnetic field in the photosphere. This is a robust result in the sense that it arises from simulations with…

Solar and Stellar Astrophysics · Physics 2009-04-15 O. Steiner , R. Rezaei , R. Schlichenmaier , W. Schaffenberger , S. Wedemeyer-Böhm

Aims. To investigate the performance of a deconvolution map-making algorithm for an experiment with a circular scanning strategy, specifically in this case for the analysis of Planck data, and to quantify the effects of making maps using…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 D. L. Harrison , F. van Leeuwen , M. A. J. Ashdown

We consider the optical properties of the solar gravitational lens (SGL) treating the Sun as a massive compact body. Using our previously developed wave-optical treatment of the SGL, we convolve it with a thin-lens representing an optical…

Instrumentation and Methods for Astrophysics · Physics 2022-08-29 Slava G. Turyshev , Viktor T. Toth

The evolution of small magnetic features in quiet regions of the Sun provides a unique window to probing solar magneto-convection. Here we analyze small scale magnetic features in the quiet Sun, using the high resolution, seeing-free…

Solar and Stellar Astrophysics · Physics 2017-02-01 L. S. Anusha , Sami K. Solanki , Johann Hirzberger , Alex Feller

Material decomposition for imaging multiple contrast agents in a single acquisition has been made possible by spectral CT: a modality which incorporates multiple photon energy spectral sensitivities into a single data collection. This work…

Medical Physics · Physics 2020-08-11 Matthew Tivnan , Steven Tilley , J. Webster Stayman

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

We propose a new method to search for light (pseudo-)scalar particles in the spectra of compact astrophysical objects such as magnetars, pulsars, and quasars. On accounts of compact astrophysical objects having intense magnetic fields…

Astrophysics · Physics 2008-10-20 Doron Chelouche , Raul Rabadan , Sergey Pavlov , Francisco Castejon

Hyperspectral image (HSI) denoising is a crucial preprocessing procedure for the subsequent HSI applications. Unfortunately, though witnessing the development of deep learning in HSI denoising area, existing convolution-based methods face…

Computer Vision and Pattern Recognition · Computer Science 2022-11-28 Miaoyu Li , Ying Fu , Yulun Zhang

Refraction deflects photons that pass through atmospheres, which affects transit light curves. Refraction thus provides an avenue to probe physical properties of exoplanet atmospheres and to constrain the presence of clouds and hazes. In…

Earth and Planetary Astrophysics · Physics 2018-01-24 Dennis Alp , Brice-Olivier Demory

We present a new method for joint likelihood deconvolution (Jolideco) of a set of astronomical observations of the same sky region in the presence of Poisson noise. The observations may be obtained from different instruments with different…

Instrumentation and Methods for Astrophysics · Physics 2024-03-22 Axel Donath , Aneta Siemiginowska , Vinay L. Kashyap , David A. van Dyk , Douglas Burke

Point-spread function (PSF) estimation in spatially undersampled images is challenging because large pixels average fine-scale spatial information. This is problematic when fine-resolution details are necessary, as in optimal photometry…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 Teresa Symons , Michael Zemcov , James Bock , Yun-Ting Cheng , Brendan Crill , Christopher Hirata , Stephanie Venuto

In order to avoid collisions with space debris, the near Earth orbit must be continuously scanned by either ground- or spaced-based facilities. For the low Earth orbit, radar telescopes are the workhorse for this task, especially due to…

Instrumentation and Methods for Astrophysics · Physics 2015-01-26 Daniel Hampf , Paul Wagner , Wolfgang Riede
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