62 citations · 214 across the 25 of their papers we have counts for
26 papers
Count-based spectral component imaging (CCI) of solar flares in X-rays
Alessia Guidetti, Muriel Zoë Stiefel, Paolo Massa +3
X-ray emission in solar flares is produced by both multi-thermal plasma and accelerated electrons. Classical imaging approaches reconstruct X-ray intensity maps which contain contr…
Greedy techniques for inverse problems
L. Bruni Bruno, P. Massa, E. Perracchione +1
Inverse imaging problems rely on limited and indirect measurements, making reconstruction highly dependent on both regularization and sample locations. We introduce a novel greedy…
Radio, X-ray, and EUV signatures of internal and external reconnection of an erupting flux rope
Jana Kašparová, Jaroslav Dudík, Marian Karlický +5
We analyse imaging (EUV, X-ray) and spectral (radio, X-ray) data obtained by ground based and space instruments on board space missions both on Earth (Fermi, Hinode, Solar Dynamics…
Spectral component imaging of solar X-ray flares
Muriel Zoë Stiefel, Paolo Massa, Alessia Guidetti +2
Solar hard X-ray observations provide diagnostics of the hottest plasmas and of nonthermal electron populations present during solar flares and coronal mass ejections. HXR images o…
PRESOL: a web-based computational setting for feature-based flare forecasting
Chiara Curletto, Paolo Massa, Valeria Tagliafico +4
Solar flares are the most explosive phenomena in the solar system and the main trigger of the events' chain that starts from Coronal Mass Ejections and leads to geomagnetic storms…
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…
Convergence rates for Tikhonov regularization on compact sets: application to neural networks
Barbara Palumbo, Paolo Massa, Federico Benvenuto
In this work, we consider ill-posed inverse problems in which the forward operator is continuous and weakly closed, and the sought solution belongs to a weakly closed constraint se…
Enhancing Image Resolution of Solar Magnetograms: A Latent Diffusion Model Approach
Francesco Pio Ramunno, Paolo Massa, Vitaliy Kinakh +3
The spatial properties of the solar magnetic field are crucial to decoding the physical processes in the solar interior and their interplanetary effects. However, observations from…
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…
A machine learning approach for computing solar flare locations in X-rays on-board Solar Orbiter/STIX
Paolo Massa, Simon Felix, László István Etesi +7
The Spectrometer/Telescope for Imaging X-rays (STIX) on-board the ESA Solar Orbiter mission retrieves the coordinates of solar flare locations by means of a specific sub-collimator…
Identifying synergies between VLBI and STIX imaging
Hendrik Müller, Paolo Massa, Alejandro Mus +2
Reconstructing an image from sparsely sampled Fourier data is an ill-posed inverse problem that occurs in a variety of subjects within science, including the data analysis for Very…
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…
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…
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…
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…
The data center for the Spectrometer and Telescope for Imaging X-rays (STIX) onboard Solar Orbiter
Hualin Xiao, Shane Maloney, Säm Krucker +12
The Spectrometer and Telescope for Imaging X-rays (STIX) on board Solar Orbiter observes solar X-ray emission in the range of 4 – 150 keV and produces spectra and images of s…
Robust construction of differential emission measure profiles using a regularized maximum likelihood method
Paolo Massa, A. Gordon Emslie, Iain G. Hannah +1
Extreme-ultraviolet (EUV) observations provide considerable insight into evolving physical conditions in the active solar atmosphere. For a prescribed density and temperature struc…
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…
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…
Regularization from examples via neural networks for parametric inverse problems: topology matters
Paolo Massa, Sara Garbarino, Federico Benvenuto
In this work we deal with parametric inverse problems, which consist in recovering a finite number of parameters describing the structure of an unknown object, from indirect measur…
Imaging from STIX visibility amplitudes
Paolo Massa, Emma Perracchione, Sara Garbarino +5
Aims: To provide the first demonstration of STIX Fourier-transform X-ray imaging using semi-calibrated (amplitude-only) visibility data acquired during the Solar Orbiter's cruise p…
STIX X-ray microflare observations during the Solar Orbiter commissioning phase
Andrea Francesco Battaglia, Jonas Saqri, Paolo Massa +34
The Spectrometer/Telescope for Imaging X-rays (STIX) is the HXR instrument onboard Solar Orbiter designed to observe solar flares over a broad range of flare sizes, between 4-150 k…
Visibility Interpolation in Solar Hard X-ray Imaging: Application to RHESSI and STIX
Emma Perracchione, Paolo Massa, Anna Maria Massone +1
Space telescopes for solar hard X-ray imaging provide observations made of sampled Fourier components of the incoming photon flux. The aim of this study is to design an image recon…
Predictive risk estimation for the Expectation Maximization algorithm with Poisson data
Paolo Massa, Federico Benvenuto
In this work, we introduce a novel estimator of the predictive risk with Poisson data, when the loss function is the Kullback-Leibler divergence, in order to define a regularizatio…