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This paper employs the backward ray tracing method to study the optical images of neutron stars under the conditions of a spherical light source and a thin accretion disk, considering a polynomial equation of state given by $p = K \rho^{1 +…

General Relativity and Quantum Cosmology · Physics 2026-01-13 Chen-Yu Yang , Xiao-Xiong Zeng

We analyze two 3D general-relativistic magnetohydrodynamic accretion simulations in the context of how they would manifest in Event Horizon Telescope (EHT) observations of supermassive black holes. The two simulations differ only in whether…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Christopher J. White , Jason Dexter , Omer Blaes , Eliot Quataert

We describe a novel experimental technique for neutron imaging with scattered neutrons. These scattered neutrons are of interest for condensed matter physics, because they permit to reveal the local distribution of incoherent and coherent…

Nuclear Experiment · Physics 2007-05-23 H. Ballhausen , H. Abele , R. Gaehler , M. Trapp , A. Van Overberghe

Neutron imaging is an invaluable noninvasive technique for exploring new science and assisting industrial manufacture. However, state-of-the-art neutron facilities are extremely expensive and inconvenient to access, while the flux of…

This paper investigates the optical images of neutron stars within the framework of the radiatively inefficient accretion flow model, taking into account a polytropic equation of state. After obtaining the numerical solutions of the neutron…

General Relativity and Quantum Cosmology · Physics 2026-04-03 Chen-Yu Yang , Xiao-Xiong Zeng

We investigate the radiative decay of the cosmic neutrino background, and its impact on the spectrum of the cosmic microwave background (CMB) that is known to be a nearly perfect black body. We derive exact formulae for the decay of a…

Neutron spectrum and scattered neutrons caused distortions are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and…

Instrumentation and Detectors · Physics 2013-06-11 Liu Shu-Quan , Bücherl Thomas , Li Hang , Zou Yu-Bin , Lu Yuan-Rong , Guo Zhi-Yu

The complexity of the neutron transport phenomenon throws its shadows on every physical system wherever neutron is produced or absorbed. The Monte Carlo N-Particle Transport Code (MCNP) was used to investigate the flux perturbations in the…

High Energy Physics - Phenomenology · Physics 2022-07-25 Ateia W. Mahmoud , Elsayed K. Elmaghraby , A. H. M. Solieman , E. Salama , A. Elghazaly , S. A. El-fiki

Scattered neutron spectroscopy is a diagnostic technique commonly used to measure areal density in ICF experiments. Deleterious areal density asymmetries modify the shape of the scattered neutron spectrum. In this work a novel analysis is…

Plasma Physics · Physics 2021-12-15 Aidan Crilly , Brian Appelbe , Owen Mannion , Chad Forrest , Jeremy Chittenden

In this paper we discuss the prospects to take a picture of an extended neutrino source, i.e., resolving its angular neutrino luminosity distribution. This is challenging since neutrino directions cannot be directly measured but only…

High Energy Physics - Phenomenology · Physics 2022-08-22 Guey-Lin Lin , Thi Thuy Linh Nguyen , Martin Spinrath , Thi Dieu Hien Van , Tse-Chun Wang

In this work we explore for the first time the applicability of using $\gamma$-ray imaging in neutron capture measurements to identify and suppress spatially localized background. For this aim, a pinhole gamma camera is assembled, tested…

Currently envisioned extensions of the Event Horizon Telescope to space will soon target the black hole photon ring: a narrow ring-shaped imprint of a black hole's strong gravity produced in its images by highly bent photon trajectories. In…

General Relativity and Quantum Cosmology · Physics 2024-06-24 Alejandro Cárdenas-Avendaño , Lennox Keeble , Alexandru Lupsasca

We study the implications of asymmetric dark matter on neutron stars. we construct a "mixed neutron star" model composed of ordinary baryons and of asymmetric dark matter baryons. We derive the general relativistic structure equations for…

Cosmology and Nongalactic Astrophysics · Physics 2011-12-08 Itzhak Goldman

A neutron optical transport system is proposed which comprises nested short elliptical mirrors located halfway between two common focal points M and M'. It images cold neutrons from a diverging beam or a source with finite size at M by…

Instrumentation and Detectors · Physics 2016-11-23 Oliver Zimmer

Faithfully reconstructing 3D geometry and generating novel views of scenes are critical tasks in 3D computer vision. Despite the widespread use of image augmentations across computer vision applications, their potential remains…

Computer Vision and Pattern Recognition · Computer Science 2023-06-16 Juan C. Pérez , Sara Rojas , Jesus Zarzar , Bernard Ghanem

Image deblurring is a notoriously challenging ill-posed inverse problem. In recent years, a wide variety of approaches have been proposed based upon regularization at the level of the image or on techniques from machine learning. We propose…

Computer Vision and Pattern Recognition · Computer Science 2020-10-22 Gabriel Rioux , Rustum Choksi , Tim Hoheisel , Pierre Marechal , Christopher Scarvelis

We acquired an image of the Siemens Star Chart using the ${}^{10}$B-INTPIX4 CMOS pixelated imager at J-PARC MLF BL21 (NOVA). The image blurriness, characterized by a root mean square (rms) value of 17 $\mu$m in the line spread function,…

Instrumentation and Detectors · Physics 2025-05-12 Yoshio Kamiya , Hidetoshi Ohshita , Ryutaro Nishimura , Toshiya Muto , Shingo Mitsui , Tomohiro Seya , Izumi Umegaki , Yasuo Arai

The existence of a distinct mass boundary between the heaviest neutron stars and the lightest black holes remains in question. It is an artefact of our ignorance of the properties of matter at supra-nuclear densities, which exist in the…

High Energy Astrophysical Phenomena · Physics 2026-02-23 Rounak Mukherjee , Ritam Mallick

Using general relativistic magnetohydrodynamic simulations of accreting black holes, we show that a suitable subtraction of the linear polarization per pixel from total intensity images can enhance the photon ring features. We find that the…

The extreme conditions found near black holes and neutron stars provide a unique opportunity for testing physical theories. Observations of both types of compact objects can be used to probe regions of strong gravity, allowing for tests of…

High Energy Astrophysical Phenomena · Physics 2009-02-25 John A. Tomsick , Andreas Quirrenbach , Shrinivas R. Kulkarni , Stuart B. Shaklan , Xiaopei Pan
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