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Related papers: Parameter constraints for accreting millisecond pu…

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We present the results of {\it Chandra} observations of two non-accreting millisecond pulsars, PSRs J1640$+$2224 (J1640) and J1709$+$2313 (J1709), with low inferred magnetic fields and spin-down rates in order to constrain their surface…

High Energy Astrophysical Phenomena · Physics 2017-05-22 Simin Mahmoodifar , Tod Strohmayer

Radiation of X-ray bursts and of accretion shocks in weakly magnetized neutron stars in low-mass X-ray binaries is produced in plane-parallel atmospheres dominated by electron scattering. We first discuss polarization produced by single…

High Energy Astrophysical Phenomena · Physics 2016-06-01 Juri Poutanen

Peak to average power ratio (PAPR) constrained power allocation in single carrier multiuser (MU) single-input multiple-output (SIMO) systems with iterative frequency domain (FD) soft cancelation (SC) minimum mean squared error (MMSE)…

Information Theory · Computer Science 2016-11-17 Valtteri Tervo , Antti Tölli , Juha Karjalainen , Tad Matsumoto

Accurate thermal emission models of neutron stars are essential for constraining the dense matter equation of state. However, incorporating realistic magnetic field structures is computationally prohibitive, severely constraining feasible…

Nuclear magnetic resonance (NMR) and magnetic resonance imaging (MRI) suffer from inherently low sensitivity due to the weak thermal polarization of nuclear spins. Parahydrogen-induced polarization (PHIP) offers a powerful route to enhance…

Instrumentation and Detectors · Physics 2025-10-28 Yenal Gökpek , Jan-Bernd Hövener , Andrey N. Pravdivtsev

Most models of anomalous X-ray pulsars (AXPs) account for the observed X-ray spectra and pulsations by means of radiation processes that occur on the surfaces of neutron stars. For any such model, general relativistic deflection of light…

Astrophysics · Physics 2009-10-31 Simon DeDeo , Dimitrios Psaltis , Ramesh Narayan

Mueller matrix (MM) polarimetry is an effective, non-invasive tool for retrieving information from complex media. However, the finite dynamic range of optical detectors poses a significant challenge when measurements involve strong…

Optics · Physics 2026-04-27 Lourdes Camblor-Navarro , Iago Pardo , Oriol Arteaga

A neutron star (NS) accreting matter from a companion star in a low-mass X-ray binary (LMXB) system can spin up to become a millisecond pulsar (MSP). Properties of many such MSP systems are known, which is excellent for probing fundamental…

High Energy Astrophysical Phenomena · Physics 2024-10-11 Abhijnan Kar , Pulkit Ojha , Sudip Bhattacharyya

By analyzing the Rossi X-ray Timing Explorer data on SAX J1808.4-3658 we show that the X-ray emission in accretion powered millisecond pulsars can be produced by Comptonization in a hot slab (radiative shock) of Thomson optical depth tau~1…

Astrophysics · Physics 2009-11-10 Juri Poutanen

We present an empirical model for single pulses of radio emission from pulsars based on gaussian probability distributions for relevant variables. The radiation at a specific pulse phase is represented as the superposition of radiation in…

Astrophysics · Physics 2009-11-13 D. Melrose , A. Miller , A. Karastergiou , Q. Luo

Modeling non-empirical and highly flexible interatomic potential energy surfaces (PES) using machine learning (ML) approaches is becoming popular in molecular and materials research. Training an ML-PES is typically performed in two stages:…

Materials Science · Physics 2021-01-05 Suresh Kondati Natarajan , Miguel A. Caro

The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Roberto Taverna , Fabio Muleri , Roberto Turolla , Paolo Soffitta , Sergio Fabiani , Luciano Nobili

Machine-learning-based interatomic potential energy surface (PES) models are revolutionizing the field of molecular modeling. However, although much faster than electronic structure schemes, these models suffer from costly computations via…

Computational Physics · Physics 2022-08-08 Denghui Lu , Wanrun Jiang , Yixiao Chen , Linfeng Zhang , Weile Jia , Han Wang , Mohan Chen

This paper addresses the problem of learning the impulse responses characterizing forward models by means of a regularized kernel-based Prediction Error Method (PEM). The common approach to accomplish that is to approximate the system with…

Optimization and Control · Mathematics 2024-09-20 Giulio Fattore , Marco Peruzzo , Giacomo Sartori , Mattia Zorzi

We introduce the concept of Plasmonic Parametric Resonance (PPR) as a novel way to amplify high angular momentum plasmonic modes of nanoparticles by means of a simple uniform optical pump. In analogy with parametric resonance in dynamical…

Optics · Physics 2018-02-13 Alessandro Salandrino

We present a model for the anomalous X-ray pulsars (AXPs) in which the emission is powered by accretion from a fossil disk, established from matter falling back onto the neutron star following its birth. The time-dependent accretion drives…

Astrophysics · Physics 2009-10-31 Pinaki Chatterjee , Lars Hernquist , Ramesh Narayan

We propose a new algorithm to learn the network of the interactions of pairwise Ising models. The algorithm is based on the pseudo-likelihood method (PLM), that has already been proven to efficiently solve the problem in a large variety of…

Disordered Systems and Neural Networks · Physics 2019-02-19 Silvio Franz , Federico Ricci-Tersenghi , Jacopo Rocchi

A complete set of diagnostic tools aimed at producing synthetic synchrotron emissivity, polarization, and spectral index maps from relativistic MHD simulations is presented. As a first application we consider here the case of the emission…

Astrophysics · Physics 2009-11-11 Luca Del Zanna , Delia Volpi , Elena Amato , Niccolo' Bucciantini

Current Scene text image super-resolution approaches primarily focus on extracting robust features, acquiring text information, and complex training strategies to generate super-resolution images. However, the upsampling module, which is…

Computer Vision and Pattern Recognition · Computer Science 2023-09-19 Wenyu Zhang , Xin Deng , Baojun Jia , Xingtong Yu , Yifan Chen , jin Ma , Qing Ding , Xinming Zhang

The pulse profiles of the accreting X-ray millisecond pulsar SAX J1808.4-3658 at different energies are studied. The two main emission component, a black body and a power-law tail, clearly identified in the time-averaged spectrum, do not…

Astrophysics · Physics 2007-05-23 Juri Poutanen , Marek Gierlinski
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