activity
20222025
most citedForward-fitting STIX visibilities

28 citations · 65 across the 14 of their papers we have counts for

collaborators

14 papers

astro-ph.SR2025

CLEAN and multi-scale CLEAN for STIX in Solar Orbiter

Miriana Catalano, Anna Volpara, Paolo Massa +2

CLEAN is a well-established deconvolution approach to Fourier imaging at both radio wavelwengths and hard X-ray energies. However, specifically for hard X-ray imaging, CLEAN suffer…

math.NA2025

Variably Scaled Kernels for the regularized solution of the parametric Fourier imaging problem

Anna Volpara, Alessandro Lupoli, Emma Perracchione

We address the problem of approximating parametric Fourier imaging problems via interpolation/ extrapolation algorithms that impose smoothing constraints across contiguous values o…

astro-ph.SR2025

Solar flares as electron accelerators: toward a resolution of the acceleration efficiency issue

Anna Volpara, Paolo Massa, Michele Piana +2

A major open issue concerning the active Sun is the effectiveness with which magnetic reconnection accelerates electrons in flares. A paper published by {\em{Nature}} in 2022 used…

astro-ph.SR2025★ 13 cited

Using the STIX background detector as a proxy for GOES

Muriel Zoë Stiefel, Matej Kuhar, Olivier Limousin +4

Context. The Spectrometer/Telescope for Imaging X-Rays (STIX) onboard Solar Orbiter was designed to observe solar flares in the X-ray range of 4-150 keV, providing spectral, tempor…

astro-ph.SR2024

RIS: Regularized Imaging Spectroscopy for STIX on-board Solar Orbiter

Anna Volpara, Alessandro Lupoli, Frank Filbir +3

Imaging spectroscopy, i.e., the generation of spatially resolved count spectra and of cubes of count maps at different energies, is one of the main goals of solar hard X-ray missio…

astro-ph.SR2024

AI-FLARES: Artificial Intelligence for the Analysis of Solar Flares Data

Michele Piana, Federico Benvenuto, Anna Maria Massone +6

AI-FLARES (Artificial Intelligence for the Analysis of Solar Flares Data) is a research project funded by the Agenzia Spaziale Italiana and by the Istituto Nazionale di Astrofisica…

astro-ph.SR2023

Variation of the electron flux spectrum along a solar flare loop as inferred from STIX hard X-ray observations

Anna Volpara, Paolo Massa, Sam Krucker +3

Regularized imaging spectroscopy was introduced for the construction of electron flux images at different energies from count visibilities recorded by the Reuven Ramaty High Energy…

astro-ph.IM2023

Unbiased CLEAN for STIX in Solar Orbiter

Emma Perracchione, Fabiana Camattari, Anna Volpara +3

Aims: To formulate, implement, and validate a user-independent release of CLEAN for Fourier-based image reconstruction of hard X-rays flaring sources. Methods: CLEAN is an iterativ…

math.NA2023

Mapped Variably Scaled Kernels: Applications to Solar Imaging

Francesco Marchetti, Emma Perracchione, Anna Volpara +3

Variably scaled kernels and mapped bases constructed via the so-called fake nodes approach are two different strategies to provide adaptive bases for function interpolation. In thi…

astro-ph.IM2023

Multi-scale CLEAN in hard X-ray solar imaging

Anna Volpara, Michele Piana, Anna Maria Massone

Multi-scale deconvolution is an ill-posed inverse problem in imaging, with applications ranging from microscopy, through medical imaging, to astronomical remote sensing. In the cas…

astro-ph.IM2023

STIX imaging I -- Concept

Paolo Massa, Gordon. J. Hurford, Anna Volpara +17

Aims. To provide a schematic mathematical description of the imaging concept of the Spectrometer/Telescope for Imaging X-rays (STIX) on board Solar Orbiter. The derived model is th…

astro-ph.SR2022★ 24 cited

Solar flare hard X-rays from the anchor points of an eruptive filament

Muriel Zoë Stiefel, Andrea Francesco Battaglia, Krzysztof Barczynski +7

Context. We present an analysis of a GOES M1.8 flare with excellent observational coverage in UV, EUV, and X-ray, including observations from the instruments IRIS, SDO with AIA, Hi…

astro-ph.SR2022★ 28 cited

Forward-fitting STIX visibilities

Anna Volpara, Paolo Massa, Emma Perracchione +6

Aima. To determine to what extent the problem of forward fitting visibilities measured by the Spectrometer/Telescope Imaging X-rays (STIX) on-board Solar Orbiter is more challengin…

astro-ph.SR2022

First hard X-ray imaging results by Solar Orbiter STIX

Paolo Massa, Andrea F. Battaglia, Anna Volpara +15

Context. The Spectrometer/Telescope for Imaging X-rays (STIX) is one of 6 remote sensing instruments on-board Solar Orbiter. It provides hard X-ray imaging spectroscopy of solar fl…