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Strong magnetic fields, synchrotron emission, and Compton scattering are omnipresent in compact celestial X-ray sources. Emissions in the X-ray energy band are consequently expected to be linearly polarized. X-ray polarimetry provides a…

High Energy Astrophysical Phenomena · Physics 2017-06-29 M. Chauvin , H. -G. Florén , M. Friis , M. Jackson , T. Kamae , J. Kataoka , T. Kawano , M. Kiss , V. Mikhalev , T. Mizuno , N. Ohashi , T. Stana , H. Tajima , H. Takahashi , N. Uchida , M. Pearce

We have developed a new technique for weak lensing analysis, with which the effect of the point spread function (PSF) on small galaxy images can be corrected for accurately. Rather than relying on weighted second moments of detected images,…

Astrophysics · Physics 2016-08-30 Konrad Kuijken

Pulsars are well studied all over the electromagnetic spectrum, and the Crab pulsar may be the most studied object in the sky. Nevertheless, a high-quality optical to near-infrared spectrum of the Crab or any other pulsar has not been…

High Energy Astrophysical Phenomena · Physics 2019-09-18 J. Sollerman , J. Selsing , P. M. Vreeswijk , P. Lundqvist , A. Nyholm

Optical microscopy is an essential tool in biology and medicine. Imaging thin, yet non-flat objects in a single shot (without relying on more sophisticated sectioning setups) remains challenging as the shallow depth of field that comes with…

Image and Video Processing · Electrical Eng. & Systems 2020-10-14 Adrian Shajkofci , Michael Liebling

Ultrasound imaging systems rely on accurate point spread function (PSF) estimation to support advanced image quality enhancement techniques such as deconvolution and speckle reduction. Phase aberration, caused by sound speed inhomogeneity…

Signal Processing · Electrical Eng. & Systems 2025-02-24 Wei-Hsiang Shen , Yu-An Lin , Meng-Lin Li

We report Spitzer 3.6 and 4.5 $\mu$m photometry of 11 bright stars relative to Sirius, exploiting the unique optical stability of the Spitzer Space Telescope point spread function (PSF). Spitzer's extremely stable beryllium optics in its…

Solar and Stellar Astrophysics · Physics 2022-01-12 Kate Y. L. Su , G. H. Rieke , M. Marengo , Everett Schlawin

We propose a compact snapshot monocular depth estimation technique that relies on an engineered point spread function (PSF). Traditional approaches used in microscopic super-resolution imaging such as the Double-Helix PSF (DHPSF) are…

Image and Video Processing · Electrical Eng. & Systems 2022-08-05 Bhargav Ghanekar , Vishwanath Saragadam , Dushyant Mehra , Anna-Karin Gustavsson , Aswin Sankaranarayanan , Ashok Veeraraghavan

A flexible apparatus for calibration of the absolute flux at the focal plane of the X-ray Source of a Powder Diffractometer, based on a fast scintillator counter, is presented. The measured fluxes, depending on the high voltage on the X-ray…

Instrumentation and Detectors · Physics 2020-08-27 Emmanuel Fokitis , Theodoros Geralis , Stavros Maltezos , Nikolaos Vodinas

The Crab Nebula is used by many instruments as a calibration source, in particular at high energy, where it is one of the brightest celestial object. The spectrometer INTEGRAL SPI (20 keV - 8 MeV), in operation since October 2002, offers a…

High Energy Astrophysical Phenomena · Physics 2020-09-02 E. Jourdain , J. P. Roques

The SPI spectrometer aboard the INTEGRAL mission observes regularly the Crab Nebula since 2003. We report on observations distributed over 5.5 years and investigate the variability of the intensity and spectral shape of this remarkable…

High Energy Astrophysical Phenomena · Physics 2015-05-14 E. Jourdain , J. P. Roques

Astrometric precision and knowledge of the point spread function are key ingredients for a wide range of astrophysical studies including time-delay cosmography in which strongly lensed quasar systems are used to determine the Hubble…

Instrumentation and Methods for Astrophysics · Physics 2021-09-22 Geoff C. -F. Chen , Tommaso Treu , Christopher D. Fassnacht , Sam Ragland , Thomas Schmidt , Sherry H. Suyu

A point spread function (PSF) describes the distribution of light for a pure point source in an astronomical image due to the optics of the instrument. An accurate PSF is key for deconvolution, point source photometry and source removal.…

Instrumentation and Methods for Astrophysics · Physics 2025-07-28 Ava Polzin

We introduce a novel framework for upsampled Point Spread Function (PSF) modeling using pixel-level Bayesian inference. Accurate PSF characterization is critical for precision measurements in many fields including: weak lensing, astrometry,…

Instrumentation and Methods for Astrophysics · Physics 2025-11-26 Connor Stone , Ronan Legin , Alexandre Adam , Nikolay Malkin , Gabriel Missael Barco , Laurence Perreaul-Levasseur , Yashar Hezaveh

Since GRBs fade rapidly, it is important to publish accurate, precise positions at early times. For Swift-detected bursts, the best promptly available position is most commonly the X-ray Telescope (XRT) position. We present two processes,…

Astrophysics · Physics 2010-03-19 P. A. Evans , A. P. Beardmore , M. R. Goad , J. P. Osborne , D. N. Burrows , N. Gehrels

With the arrival of the next generation of ultra-deep optical imaging surveys reaching $\mu_V$$\sim$30 mag/arcsec$^2$ (3$\sigma$; 10"$\times$10"), the removal of scattered light due to the point spread function (PSF) effect remains a…

We present spectral analysis of the Crab Nebula obtained with the {\it Chandra} X-ray observatory. The X-ray spectrum is characterized by a power-law whose index varies across the nebula. The variation can be discussed in terms of the…

Astrophysics · Physics 2009-11-10 K. Mori , D. N. Burrows , J. J. Hester , G. G. Pavlov , S. Shibata , H. Tsunemi

We have measured variations in scattering time scales in the Crab Pulsar over a 30-year period, using observations made at 610 MHz with the 42-ft telescope at Jodrell Bank Observatory. Over more recent years, where regular Lovell Telescope…

High Energy Astrophysical Phenomena · Physics 2018-07-18 J. W. McKee , A. G. Lyne , B. W. Stappers , C. G. Bassa , C. A. Jordan

This paper presents CSST-PSFNet, a deep learning method for high-fidelity point spread function (PSF) reconstruction developed for the Chinese Space Station Survey Telescope (CSST). The model integrates a residual neural network, a…

Instrumentation and Methods for Astrophysics · Physics 2026-03-12 Peipei Wang , Peng Wei , Chao Liu , Rui Wang , Feng Wang , Xin Zhang

We present a semi-analytical model to simulate bidirectional reflectance distribution function (BRDF) spectra of a rough slab layer containing impurities. This model has been optimized for fast computation in order to analyze hyperspectral…

Photometric surveys require precise point spread function (PSF) characterization, as it varies across filters and is crucial for accurate photometry and low surface brightness (LSB) studies. However, the small PSF size provided by default…

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