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Continuum emission from a solar flare observed with the Extreme ultraviolet Imaging Spectrometer (EIS) on board the Hinode satellite is used to obtain the radiometric calibration of the instrument. The flare had a GOES class of M8, and…

Solar and Stellar Astrophysics · Physics 2026-05-07 Peter R. Young , Biswajit Mondal

How much energy do solar active regions (ARs) typically radiate during quiescent periods? This is a fundamental question for storage and release models of flares and ARs, yet it is presently poorly answered by observations. Here we use the…

Solar and Stellar Astrophysics · Physics 2020-09-30 Maria D. Kazachenko , Hugh Hudson

The extreme-ultraviolet (EUV) late phase of solar flares is a second peak of warm coronal emissions (e.g., Fe XVI) for many minutes to a few hours after the GOES soft X-ray peak. It was first observed by the EUV Variability Experiment (EVE)…

Solar and Stellar Astrophysics · Physics 2015-06-22 Y. Li , M. D. Ding , Y. Guo , Y. Dai

We conduct a wide-band X-ray spectral analysis in the energy range of 1.5-100 keV to study the time evolution of the M7.6 class flare of 2016 July 23, with the Miniature X-ray Solar Spectrometer (MinXSS) CubeSat and the Reuven Ramaty High…

Solar and Stellar Astrophysics · Physics 2022-07-20 Shunsaku Nagasawa , Tomoko Kawate , Noriyuki Narukage , Tadayuki Takahashi , Amir Caspi , Thomas N. Woods

We present a comprehensive study of three large long-duration flares detected on an active M-dwarf binary EQ Peg using the Soft X-Ray Telescope of the AstroSat observatory. The peak X-ray luminosities of the flares in the 0.3 - 7 keV band…

Solar and Stellar Astrophysics · Physics 2021-11-16 Subhajeet Karmakar , Sachindra Naik , Jeewan C. Pandey , Igor S. Savanov

Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1 MeV,…

Astrophysics · Physics 2009-11-11 J. Kiener , M. Gros , V. Tatischeff , G. Weidenspointner

We present an analysis of seven flares detected from five RS CVn-type binaries (UZ Lib, \sigma Gem, \lambda And, V711 Tau and EI Eri) observed with XMM-Newton observatory. The quiescent state X-ray luminosities in the energy band of…

Solar and Stellar Astrophysics · Physics 2011-10-11 J. C. Pandey , K. P. Singh

We perform Differential Emission Measure (DEM) analysis of an M7.7 flare that occurred on 2012 July 19 and was well observed by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamic Observatory. Using the observational data with…

Solar and Stellar Astrophysics · Physics 2015-06-19 J. Q. Sun , X. Cheng , M. D. Ding

The first simultaneous observations of the Fe XVIII 974.86 {\AA} and Fe XX 721.56 {\AA} forbidden lines from the Spectral Imaging of the Coronal Environment (SPICE) spectrograph on Solar Orbiter are presented. The lines were observed from…

Solar and Stellar Astrophysics · Physics 2025-05-02 Peter R. Young , Andrew R. Inglis , Graham S. Kerr , Therese A. Kucera , Daniel F. Ryan

Solar flares are complex phenomena emitting all types of electromagnetic radiation, and accelerating particles on timescales of minutes, converting magnetic energy to thermal, radiative, and kinetic energy through magnetic reconnections. As…

Solar and Stellar Astrophysics · Physics 2023-09-01 Crisel Suarez , Christopher S. Moore

We perform an analysis of the line-of-sight (LOS) observables of the SDO/HMI for models of the solar atmosphere heated by precipitating high-energy electrons during solar flares. The radiative hydrodynamic (RADYN) flare models are obtained…

Solar and Stellar Astrophysics · Physics 2020-04-15 Viacheslav M Sadykov , Alexander G Kosovichev , Irina N Kitiashvili , Graham S Kerr

Context. The remote observations of solar flare ion acceleration are rather limited. There are theoretical predictions for signatures of ion acceleration in EUV line profiles. Previous tests involve observations of flares with no evidence…

Solar and Stellar Astrophysics · Physics 2018-09-19 R. Bucik , A. Fludra , R. Gomez-Herrero , D. E. Innes , B. Kellett , R. Kumar , S. Mackovjak

Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) onboard the Geostationary Operational Environmental Satellite…

Solar and Stellar Astrophysics · Physics 2013-03-07 Daniel F. Ryan , Ryan O. Milligan , Peter T. Gallagher , Brian R. Dennis , A. Kim Tolbert , Richard A. Schwartz , C. Alex Young

We demonstrate the calculation of solar wind electron bulk parameters from recent observations by Solar Wind Analyser Electron Analyser System on board Solar Orbiter. We use our methods to derive the electron bulk parameters in a time…

Aims: This paper aims to demonstrate the importance of short-exposure extreme ultraviolet (EUV) observations of solar flares in the study of particle acceleration, heating and energy partition in flares. This work highlights the…

Aims: To understand the contribution of active region and flare plasmas to the $\lambda$195 channels of SOHO/EIT (Extreme-ultraviolet Imaging Telescope) and TRACE (Transition Region and Coronal Explorer). Methods: We have analysed an M8…

Astrophysics · Physics 2009-06-25 D. Tripathi , G. Del Zanna , H. E. Mason , C. Chifor

Solar physicists routinely utilize observations of Ar-like Fe IX and Cl-like Fe X emission to study a variety of solar structures. However, unidentified lines exist in the Fe IX and Fe X spectra, greatly impeding the spectroscopic…

Line ratio of $3d-2p$ transition lines in boron-like spectra of Si X, S XII, Ar XIV and Fe XXII has been investigated. Collisional-radiative model calculations reveal that the line ratio is sensitive to the electron density in ranges of…

Astrophysics · Physics 2009-11-13 Guiyun Liang , Gang Zhao

We analyse the temporal evolution of the Differential Emission Measure (DEM) of solar active regions and explore its usage in solar flare prediction. The DEM maps are provided by the Gaussian Atmospheric Imaging Assembly (GAIA-DEM) archive,…

Solar and Stellar Astrophysics · Physics 2020-11-13 C. Gontikakis , I. Kontogiannis , M. K. Georgoulis , C. Guennou , P. Syntelis , S. H. Park , E. Buchlin

The SDO EUV observations have revealed interesting characteristics of warm coronal emissions, which peak soon after the hot coronal X-ray emissions peak during a flare and then sometimes peak for a second time hours after the X-ray flare…

Solar and Stellar Astrophysics · Physics 2015-06-18 Thomas N. Woods