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Solar Orbiter conducted a series of flare-optimised observing campaigns in 2024 utilising the Major Flare Solar Orbiter Observing Plan (SOOP). Dedicated observations were performed during two distinct perihelia intervals in March/April and…

We report on the results of a systematic study of X-ray flares from low-mass young stellar objects, using Chandra observations of the main region of the Rho Oph. From 195 X-ray sources, including class I-III sources and some young brown…

Astrophysics · Physics 2015-06-24 K. Imanishi , H. Nakajima , M. Tsujimoto , K. Koyama , Y. Tsuboi

We have analyzed multi-wavelength observations and magnetic-field data for the solar flare of May 10, 2012 (04:18 UT) and have detected a sign inversion of the signal in the line-of-sight magnetic measurements in the umbra of a small spot.…

Solar and Stellar Astrophysics · Physics 2016-10-19 M. A. Livshits , I. Yu. Grigoryeva , I. I. Myshyakov , G. V. Rudenko

We aim to perform a statistical study of stellar flares observed by Kepler. We want to study the flare amplitude, duration, energy and occurrence rates, and how they are related to the spectral type and rotation period. To that end, we have…

Solar and Stellar Astrophysics · Physics 2017-11-08 Tom Van Doorsselaere , Hoda Shariati , Jonas Debosscher

We investigate the properties of a set of solar flares originating from a single active region (AR) that exhibit QPPs, and look for signs of the QPP periods relating to AR properties. The AR studied, best known as NOAA 12192, was unusually…

Solar and Stellar Astrophysics · Physics 2017-12-13 C. E. Pugh , V. M. Nakariakov , A. -M. Broomhall , A. V. Bogomolov , I. N. Myagkova

There is no list of bipolar active regions (ARs) with reverse polarity (anti-Hale regions), although statistical investigations of such ARs (bearing the imprint of deep subphotospheric processes) are important for understanding solar-cycle…

Solar and Stellar Astrophysics · Physics 2020-12-09 A. Zhukova , A. Khlystova , V. Abramenko , D. Sokoloff

We report a NuSTAR observation of a solar microflare, SOL2015-09-01T04. Although it was too faint to be observed by the GOES X-ray Sensor, we estimate the event to be an A0.1 class flare in brightness. This microflare, with only 5 counts…

We generated an event catalog with an automated detection algorithm based on the entire EUVI image database observed with the two Solar Terrestrial Relations Observatory STEREO-A and -B spacecraft over the first six years of the mission…

Solar and Stellar Astrophysics · Physics 2015-06-16 Aschwanden , M. J. , Wuelser , J. P. , Nariaki , N. V. , Lemen , J. R. , Thompson , W. T

We present an overview of solar flares and associated phenomena, drawing upon a wide range of observational data primarily from the RHESSI era. Following an introductory discussion and overview of the status of observational capabilities,…

The High Altitude Water Cherenkov (HAWC) Observatory monitors the gamma-ray sky in the 100 GeV to 100 TeV energy range with > 95% uptime and unprecedented sensitivity for a survey instrument. The HAWC Collaboration has implemented an online…

High Energy Astrophysical Phenomena · Physics 2019-08-13 Thomas Weisgarber , Ian G. Wisher

Flares from the Sun and other stars are most prominently observed in the soft X-ray band. Most of the radiated energy, however, is released at optical/UV wavelengths. In spite of decades of investigation, the physics of flares is not fully…

Solar and Stellar Astrophysics · Physics 2018-12-05 E. Flaccomio , G. Micela , S. Sciortino , A. M. Cody , M. G. Guarcello , M. Morales-Calderòn , L. Rebull , J. R. Stauffer

Solar flares are highly energetic events that happen in the solar atmosphere. They are mostly observed as X-ray or gamma-ray bursts located on the Sun's surface. While they are known to be sites of particle acceleration, the acceleration…

Solar and Stellar Astrophysics · Physics 2023-10-25 Jonathan Mauro , Gwenhaël de Wasseige

The study of nonstationary processes in the Sun is of great interest, and lately, multiwavelength observations and registration of magnetic fields are carried out by means of both ground-based telescopes and several specialized spacecraft…

Solar flares originate from magnetically active regions but not all solar active regions give rise to a flare. Therefore, the challenge of solar flare prediction benefits by an intelligent computational analysis of physics-based properties…

Solar and Stellar Astrophysics · Physics 2019-10-09 Cristina Campi , Federico Benvenuto , Anna Maria Massone , D Shaun Bloomfield , Manolis K Georgoulis , Michele Piana

We analyzed the light curves of 1376 early-to-late, nearby M dwarfs to search for white-light flares using photometry from the All-Sky Automated Survey for Supernovae (ASAS-SN). We identified 480 M dwarfs with at least one potential flare…

Solar flares are explosive releases of magnetic energy. Hard X-ray (HXR) flare emission originates from both hot (millions of Kelvin) plasma and nonthermal accelerated particles, giving insight into flare energy release. The Nuclear…

We investigated how the magnetic field in solar active regions (ARs) controls flare activity, i.e., whether a confined or eruptive flare occurs. We analyzed 44 flares of GOES class M5.0 and larger that occurred during 2011--2015. We used 3D…

Solar and Stellar Astrophysics · Physics 2018-02-14 Christian Baumgartner , Julia K. Thalmann , Astrid M. Veronig

We study flare processes in the lower solar atmosphere using observational data for a M1-class flare of June 12, 2014, obtained by New Solar Telescope (NST/BBSO) and Helioseismic Magnetic Imager (HMI/SDO). The main goal is to understand…

Solar and Stellar Astrophysics · Physics 2016-04-20 I. N. Sharykin , V. M. Sadykov , A. G. Kosovichev , S. Vargas-Dominguez , I. V. Zimovets

Large solar flares (GOES M-class or higher) are usually associated with eruptions of material. However, when considering flare irradiance enhancements and dynamics such as chromospheric evaporation, potential contributions from erupted…

Solar and Stellar Astrophysics · Physics 2025-12-18 Luke Majury , Marie Dominique , Ryan Milligan , Dana-Camelia Talpeanu , Ingolf Dammasch , David Berghmans

We report the first science results from the newly completed Expanded Owens Valley Solar Array (EOVSA), which obtained excellent microwave imaging spectroscopy observations of SOL2017-09-10, a classic partially-occulted solar limb flare…