Related papers: Advanced Weights for IXPE Polarization Analysis

The last decade has seen a leapfrog in the interest in X-ray polarimetry with a number of new polarization measurements in hard X-rays from AstroSat, POLAR, GAP, and PoGO+. The measurements provide some interesting insights into various…

X-ray polarimetry missions like IXPE will be able to measure for the first time the polarization properties of accreting, weakly magnetized neutron stars in Low Mass X-ray Binaries. In this work we present simulations of the expected X-ray…

X-ray polarimetry of accreting compact objects has revealed fast time variations in the polarization angle (PA), suggesting that the geometry and/or optical depth of the Comptonization region is changing rapidly. This prompts investigations…

The surfaces of neutron stars are likely sources of strongly polarized soft X rays due to the presence of strong magnetic fields. Scattering transport in the surface layers is critical to the determination of the emergent anisotropy of…

Neural Posterior Estimation (NPE) enables rapid parameter inference for complex simulators with intractable likelihoods. NPE trains an inference network to estimate a probability density over parameters given data, typically assumed to be…

X-ray binary systems consist of a companion star and a compact object in close orbit. Thanks to their copious X-ray emission, these objects have been studied in detail using X-ray spectroscopy and timing. The inclination of these systems is…

Azimuthal asymmetries play an important role in scattering processes with polarized particles. This paper introduces a new procedure using event weighting to extract these asymmetries. It is shown that the resulting estimator has several…

Polarimetry remains a largely unexploited technique in observational X-ray astronomy which could provide insight in the study of the strong gravity and magnetic fields at the core of the Constellation-X observational program. Adding a…

The Imaging X-ray Polarimetry Explorer (IXPE) observed for the first time highly polarized X-ray emission from the magnetar 1E 1841-045, targeted after a burst-active phase in August 2024. To date, IXPE has observed four other magnetars…

Context: Polarimetry is a very powerful tool to uncover various properties of astronomical objects that remain otherwise hidden in standard imaging or spectroscopic observations. However, the reliable measurement of the low polarization…

I expand on the results of a recent work in which a novel weighting algorithm was shown to substantially increase the accuracy of an old, non-Bayesian computational approach for inferring the source direction of a gravitational wave from…

X-rays are particularly suited to probe the physics of extreme objects. However, despite the enormous improvements of X-ray Astronomy in imaging, spectroscopy and timing, polarimetry remains largely unexplored. We propose the photoelectric…

After about 16 years since its first outburst, the transient neutron star low-mass X-ray binary XTE J1701$-$462 turned on again in September 2022, allowing for the first study of its X-ray polarimetric characteristics by a dedicated…

X-ray polarimetry has the potential to make key-contributions to our understanding of galactic compact objects like binary black hole systems and neutron stars, and extragalactic objects like active galactic nuclei, blazars, and Gamma Ray…

Neural posterior estimation (NPE), a type of amortized variational inference, is a computationally efficient means of constructing probabilistic catalogs of light sources from astronomical images. To date, NPE has not been used to perform…

In astronomy there are basically four kinds of observations to extract the information carried by electromagnetic radiation: photometry, imaging, spectroscopy and polarimetry. By optimal exploitation of the first three techniques, X-ray…

The class-transition Galactic X-ray binary IGR~J17091--3624 was simultaneously monitored by the \textit{IXPE} and \textit{NuSTAR} satellites. We present a detailed spectro-polarimetric study of the source using data from both satellites…

Polarized neutrons are a powerful probe to investigate magnetism in condensed matter on length scales from single atomic distances to micrometers. With the ongoing advancement of neutron optics, that allow to transport beams with increased…

We present a new shear estimator for weak lensing observations which properly accounts for the effects of a realistic point spread function (PSF). Images of faint galaxies are subject to gravitational shearing followed by smearing with the…

Given a set of images, whose pixel values can be considered as the components of a vector, it is interesting to estimate the modulus of such a vector in some localised areas corresponding to a compact signal. For instance, the…