Article
Astronomy & Astrophysics
Anna Volpara, Paolo Massa, Emma Perracchione, Andrea Francesco Battaglia, Sara Garbarino, Federico Benvenuto, Sam Krucker, Michele Piana, Anna Maria Massone
Summary: This study compares the difficulty of solving the problem of forward fitting visibilities measured by STIX on Solar Orbiter with previous hard X-ray solar imaging missions, and seeks an effective optimization scheme. By comparing experimental and synthetic data, it is found that particle swarm optimization performs the best in terms of stability and computational effectiveness. The standard optimization based on local search is not effective enough for STIX, and more sophisticated global search optimization schemes are needed.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Xian-Kai Jiang, Jian Wu, Deng-Yi Chen, Yi-Ming Hu, Hao-Xiang Wang, Wei Liu, Zhe Zhang
Summary: This paper develops a mathematical model to analyze the modulation function of the collimator and provides valuable insights for the design and development of Fourier transform imaging telescopes. The behavior of the modulation function is calculated under six degrees of freedom by adding rotation and translation changes to the model. Additionally, the model considers unparalleled light and extended sources for X-ray beam analysis. The model is confirmed through Geant4 simulations and verification experiments, and its contribution to improving image reconstruction after the launch of ASO-S is also discussed.
RESEARCH IN ASTRONOMY AND ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Hannah Collier, Laura A. A. Hayes, Andrea F. F. Battaglia, Louise K. K. Harra, Sam Krucker
Summary: The aim of this work is to develop a method to systematically detect and characterise fast-time variations in the non-thermal hard X-ray time profiles of solar flares using high-resolution data from Solar Orbiter's STIX. The HXR time profiles were smoothed using Gaussian Process regression, and then fitted with a linear combination of Gaussians to decompose the time profile and derive key characteristics such as periodicity, full width at half maximum, time evolution, and amplitude.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
T. Mrozek, R. Falewicz, S. Kolomanski, M. Litwicka
Summary: This study investigates the deposition process of non-thermal electron beams in a solar flare through numerical simulation and analysis of observed data. The results provide estimates of the evaporated mass and contribute to a better understanding of the precipitation process of non-thermal electron beams.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Jonas Saqri, Astrid M. Veronig, Alexander Warmuth, Ewan C. M. Dickson, Andrea Francesco Battaglia, Tatiana Podladchikova, Hualin Xiao, Marina Battaglia, Gordon J. Hurford, Sam Krucker
Summary: This study used the Spectrometer/Telescope for Imaging X-rays (STIX) instrument to observe the energy release and transport in solar flares. By analyzing data from multiple instruments, the study found that two microflare events are consistent with the standard chromospheric evaporation flare scenario and that accelerated electrons can account for the required thermal energy.
ASTRONOMY & ASTROPHYSICS
(2022)
Article
Astronomy & Astrophysics
Andrea Francesco Battaglia, Jonas Saqri, Paolo Massa, Emma Perracchione, Ewan C. M. Dickson, Hualin Xiao, Astrid M. Veronig, Alexander Warmuth, Marina Battaglia, Gordon J. Hurford, Aline Meuris, Olivier Limousin, Laszlo Etesi, Shane A. Maloney, Richard A. Schwartz, Matej Kuhar, Frederic Schuller, Valliappan Senthamizh Pavai, Sophie Musset, Daniel F. Ryan, Lucia Kleint, Michele Piana, Anna Maria Massone, Federico Benvenuto, Janusz Sylwester, Michalina Litwicka, Marek Steslicki, Tomasz Mrozek, Nicole Vilmer, Frantisek Farnik, Jana Kasparova, Gottfried Mann, Peter T. Gallagher, Brian R. Dennis, Andre Csillaghy, Arnold O. Benz, Sam Krucker
Summary: STIX successfully observed solar microflares during its commissioning phase, revealing differences in temporal and spectral evolution compared to Earth-orbiting observatories. Future diagnostic efforts should focus on multi-wavelength studies to accurately describe the energetics of solar flares.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Andrea Francesco Battaglia, Wen Wang, Jonas Saqri, Tatiana Podladchikova, Astrid M. Veronig, Hannah Collier, Ewan C. M. Dickson, Olena Podladchikova, Christian Monstein, Alexander Warmuth, Frederic Schuller, Louise Harra, Saem Krucker
Summary: This study investigates the electron acceleration and energy release sites, as well as the mechanism by which accelerated electrons access interplanetary space, in the case of the SOL2021-02-18T18:05 event. By utilizing observations from Solar Orbiter, STEREO-A, and Earth, the researchers found that the onset of electron acceleration coincides with the coronal jet and radio type III bursts. They also discovered nonthermal hard X-ray emission and a curved trajectory of the ejected plasma during the microflare.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Prabir K. Mitra, Astrid M. Veronig, Bhuwan Joshi
Summary: This study investigates an M-class circular ribbon flare that occurred near a quasi-separatrix layer (QSL) and reveals the complex magnetic configuration involved. The flare originated from a region with negative magnetic patches surrounded by positive-polarity regions on three sides. A QSL structure was found near the flaring region, and RHESSI X-ray sources were identified from its footpoints. The analysis suggests that the activation of a flux rope within the fan-like lines, triggered by activities near the QSL, led to the circular ribbon flare.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Kristopher Cooper, Iain G. Hannah, Brian W. Grefenstette, Lindsay Glesener, Sam Krucker, Hugh S. Hudson, Stephen M. White, David M. Smith, Jessie Duncan
Summary: The study investigates the X-ray properties and radio properties of 10 microflares on AR12721, and examines their energy and temperature. Direct evidence of accelerated electrons in the form of non-thermal X-ray emission was found in one microflare. Additionally, the study highlights the matches between X-ray time profiles and fainter sources in the extreme-ultraviolet band, and observes evidence of photospheric magnetic flux cancellation/emergence at the footpoints of eight microflares.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Muriel Zoe Stiefel, Andrea Francesco Battaglia, Krzysztof Barczynski, Hannah Collier, Anna Volpara, Paolo Massa, Conrad Schwanitz, Sofia Tynelius, Louise Harra, Saem Krucker
Summary: In this study, a multiwavelength analysis of a GOES M1.8 flare was presented. Four nonthermal hard X-ray sources were observed, two located outside the flare loop and two at the loop ends. It was found that the outer sources are anchor points of an erupting filament and the hard X-ray emission is due to flare-accelerated electrons injected into the filament.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
Navin Chandra Joshi, Bhuwan Joshi, Prabir K. Mitra
Summary: In this study, a complex M-class solar eruptive flare with three sets of flare ribbons and 3D null-point magnetic topology in the source active region NOAA 12242 was reported. The event progressed through stages of circular ribbon appearance, flux rope construction and eruption, and enhancement in parallel ribbon brightness, showing interactions between different reconnection processes. The analyses suggest the roles of torus instability and breakout model in triggering the eruptive flare, showcasing the dynamic evolution of the flux rope in a null-point topology.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Astronomy & Astrophysics
Jonas Saqri, Astrid M. Veronig, Ewan C. M. Dickson, Tatiana Podladchikova, Alexander Warmuth, Hualin Xiao, Dale E. Gary, Andrea Francesco Battaglia, Saem Krucker
Summary: In this study, observations from different perspectives are combined to analyze a long duration eruptive C7 class flare that occurred on April 17, 2021. The dynamics and thermal properties of the flare-related plasma flows, as well as the kinematic evolution of the associated CME, are studied. The results provide valuable insights into the dynamics and energy release mechanisms of eruptive flares. Rating: 9 out of 10.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
E. Yolda, H. A. Dal
Summary: In this study, the solar flares detected in the hard X-ray data gathered by GOES from March to May 2001 were analyzed. It was found that the flares could be modeled with three different OPEA models, contrary to expectations of a single model. Additionally, there was a fluctuation in the energy of flares obtained over the course of three consecutive months.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Astronomy & Astrophysics
Pierre Astier, Nicolas Regnault
Summary: The brighter-fatter effect affects all CCD sensors to varying degrees, and accurate correction is required for cosmic shear measurements. This study presents the correction chain implemented for the CCDs of the Hyper Suprime-Cam imager, including non-linearity corrections and an electrostatic model derived from flat field images. Evidence suggests that some variance and covariances are not solely due to Poisson statistics and electrostatics, and their cause remains unknown. Size variations of stars in corrected science images offer predictions of the point spread function for faint objects with high accuracy. These findings are important for future cosmic shear surveys.
ASTRONOMY & ASTROPHYSICS
(2023)
Article
Astronomy & Astrophysics
A. Almodlej, H. Alrashed, N. Ben Nessib, M. S. Dimitrijevic
Summary: The researchers calculated energy levels, oscillator strengths, and transition probabilities for eight carbon-like ions using different methods and compared the results with experimental data, providing useful information for plasma diagnostics and modeling.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2021)
Article
Mathematics, Applied
G. Torre, R. A. Schwartz, F. Benvenuto, A. M. Massone, M. Piana
Article
Mathematics, Applied
Federico Benvenuto, Houssem Haddar, Blandine Lantz
SIAM JOURNAL ON APPLIED MATHEMATICS
(2016)
Article
Mathematics, Applied
Federico Benvenuto
SIAM JOURNAL ON NUMERICAL ANALYSIS
(2017)
Article
Astronomy & Astrophysics
Kostas Florios, Ioannis Kontogiannis, Sung-Hong Park, Jordan A. Guerra, Federico Benvenuto, D. Shaun Bloomfield, Manolis K. Georgoulis
Article
Computer Science, Theory & Methods
Sabrina Guastavino, Federico Benvenuto
STATISTICS AND COMPUTING
(2019)
Article
Astronomy & Astrophysics
F. Benvenuto, R. Schwartz, M. Piana, A. M. Massone
ASTRONOMY & ASTROPHYSICS
(2013)
Correction
Mathematics, Applied
F. Benvenuto, A. La Camera, C. Theys, A. Ferrari, H. Lanteri, M. Bertero
Article
Mathematics, Applied
Federico Benvenuto, Michele Piana
Article
Engineering, Biomedical
S. Garbarino, G. Caviglia, G. Sambuceti, F. Benvenuto, M. Piana
PHYSICS IN MEDICINE AND BIOLOGY
(2014)
Article
Mathematics, Applied
Federico Benvenuto, Cristina Campi
APPLIED MATHEMATICS LETTERS
(2019)
Article
Astronomy & Astrophysics
Cristina Campi, Federico Benvenuto, Anna Maria Massone, D. Shaun Bloomfield, Manolis K. Georgoulis, Michele Piana
ASTROPHYSICAL JOURNAL
(2019)
Article
Astronomy & Astrophysics
Sabrina Guastavino, Michele Piana, Anna Maria Massone, Richard Schwartz, Federico Benvenuto
ASTROPHYSICAL JOURNAL
(2019)
Article
Physics, Multidisciplinary
M. Piana, C. Campi, F. Benvenuto, S. Guastavino, A. M. Massone
NUOVO CIMENTO C-COLLOQUIA AND COMMUNICATIONS IN PHYSICS
(2019)
Article
Astronomy & Astrophysics
Federico Benvenuto, Michele Piana, Cristina Campi, Anna Maria Massone
ASTROPHYSICAL JOURNAL
(2018)