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Polarization plays an important role in various time-domain astrophysics to understand the magnetic fields, geometry, and environments of spatially unresolved variable sources. In this paper we present the results of laboratory and on-sky…

Instrumentation and Methods for Astrophysics · Physics 2020-04-29 Manisha Shrestha , Iain A. Steele , Andrez S. Piascik , Helen Jermak , Robert J. Smith , Chris M. Copperwheat

The key to photoelectric X-ray polarimetry is the determination of the emission direction of photoelectrons. Because of the low mass of an electron, the ionisation trajectory is not straight and the useful information needed for polarimetry…

Instrumentation and Detectors · Physics 2021-09-03 Tenglin Li , Ming Zeng , Hua Feng , Jirong Cang , Hong Li , Heng Zhang , Zhi Zeng , Jianping Cheng , Hao Ma , Yinong Liu

In a recent paper (Brown & Battye 2011), we proposed the use of integrated polarization measurements of background galaxies in radio weak gravitational lensing surveys and investigated the potential impact on the statistical measurement of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael L. Brown , Richard A. Battye

Reconstructing the unknown spectrum of a given X-ray source is a common problem in a wide range of X-ray imaging tasks. For high-energy sources, transmission measurements are mostly used to recover the X-ray spectrum, as a solution to an…

Applied Physics · Physics 2023-07-13 Arthur Walker , Alexandre Friou , Kevin Ginsburger

Imaging polarimetry is a powerful tool for detecting and characterizing exoplanets and circumstellar environments. Polarimetry allows a separation of the light coming from an unpolarized source such as a star and the polarized source such…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 H. Canovas , M. Rodenhuis , S. V. Jeffers , M. Min , C. U. Keller

Mask-based lensless cameras can be flat, thin, and light-weight, which makes them suitable for novel designs of computational imaging systems with large surface areas and arbitrary shapes. Despite recent progress in lensless cameras, the…

Image and Video Processing · Electrical Eng. & Systems 2023-01-11 Yucheng Zheng , M. Salman Asif

This paper is concerned with the image reconstruction problem when the measured data are solar hard X-ray modulation profiles obtained from the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI)} instrument. Our goal is to…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Federico Benvenuto , Richard Schwartz , Michele Piana , Anna Maria Massone

High-dimensional imaging technology has demonstrated significant research value across diverse fields, including environmental monitoring, agricultural inspection, and biomedical imaging, through integrating spatial (X*Y), spectral, and…

We are developing an imaging polarimeter by combining a fine-pixel CMOS image sensor with a coded aperture mask as part of the cipher project, aiming to achieve X-ray polarimetry in the energy range of…

Existing convex relaxation-based approaches to reconstruction in compressed sensing assume that noise in the measurements is independent of the signal of interest. We consider the case of noise being linearly correlated with the signal and…

Information Theory · Computer Science 2014-01-03 Thomas Arildsen , Torben Larsen

We present a series of numerical models suitable for X-ray polarimetry of accreting systems. Firstly, we provide a spectropolarimetric routine that integrates reflection from inner optically thick walls of a geometrical torus of arbitrary…

High Energy Astrophysical Phenomena · Physics 2024-04-09 J. Podgorný , M. Dovčiak , F. Marin

The MIT X-ray Polarimetry Beamline is a facility that we developed for testing components for possible use in X-ray polarimetry. Over the past few years, we have demonstrated that the X-ray source can generate nearly 100% polarized X-rays…

Instrumentation and Methods for Astrophysics · Physics 2024-08-22 Sarah N. T. Heine , Herman L. Marshall , Benjamin Schneider , Beverly Lamar , Nithya Kothnur , Alan Garner

We present our study on the reconstruction of photoelectron tracks in gas pixel detectors used for astrophysical X-ray polarimetry. Our work aims to maximize the performance of convolutional neural networks (CNNs) to predict the impact…

X-ray polarimetry in astronomy has not been exploited well, despite its importance. The recent innovation of instruments is changing this situation. We focus on a complementary MOS (CMOS) pixel detector with small pixel size and employ it…

The BICEP3 Polarimeter is a small aperture, refracting telescope, dedicated to the observation of the Cosmic Microwave Background (CMB) at 95GHz. It is designed to target degree angular scale polarization patterns, in particular the…

We are developing an X-ray polarimeter using micro-pixel CMOS sensors for solar flare X-ray polarimetry. The system consists of a 2.5-$\mu$m pixel CMOS image sensor with a 12.8$\times$12.8 mm$^2$ imaging area and a readout system based on a…

X-ray single particle imaging involves the measurement of a large number of noisy diffraction patterns of isolated objects in random orientations. The missing information about these patterns is then computationally recovered in order to…

Image and Video Processing · Electrical Eng. & Systems 2020-05-25 Kartik Ayyer

Lensless on-chip microscopy has shown great potential for biomedical imaging due to its large-area and high-throughput imaging capabilities. By combining the pixel super-resolution (PSR) technique, it can improve the resolution beyond the…

Image and Video Processing · Electrical Eng. & Systems 2024-09-06 Xuyang Chang , Shaowei Jiang , Yongcun Hu , Liheng Bian

Extragalactic foregrounds are known to generate significant biases in temperature-based CMB lensing reconstruction. Several techniques, which include ``source hardening'' and ``shear-only estimators'' have been proposed to mitigate…

Cosmology and Nongalactic Astrophysics · Physics 2023-01-24 Noah Sailer , Simone Ferraro , Emmanuel Schaan

The polarization modes of the cosmological microwave background are an invaluable source of information for cosmology, and a unique window to probe the energy scale of inflation. Extracting such information from microwave surveys requires…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Jerome Bobin , Florent Sureau , Jean-Luc Starck