Related papers: Global Oscillation Pattern in Succeeding Solar Fla…
The Reuven Ramaty High Energy Solar Spectrocopy Imager (RHESSI) $\gamma$-ray observations of the extraordinary GOES X25 flare SOL2003-10-28T11:10 are revisited to investigate previously reported conclusions that flare-accelerated electrons…
We present near ultraviolet (NUV:1750 - 2800\AA) and far ultraviolet (FUV: 1350 - 1750\AA) light-curves for flares on 4 nearby dMe-type stars (GJ 3685A, CR Dra, AF Psc and SDSS J084425.9+513830.5) observed with the GALEX satellite. Taking…
We first study the solar flare time sequence based on the GOES16 data. We find that the power spectrum density of the low-energy (E\leq E_{mean}) flare shows 1/f fluctuations, but the high-energy (E>E_{mean}) flare shows a flat spectrum.…
In this study, we investigate motions in the hot plasma above the flare loops during the 2017 September 10 X8.2 flare event. We examine the region to the south of the main flare arcade, where there is data from the Interface Region Imaging…
We investigate the solar flare of 20 October 2002. The flare was accompanied by quasi-periodic pulsations (QPP) of both thermal and nonthermal hard X-ray emissions (HXR) observed by RHESSI in the 3-50 keV energy range. Analysis of the HXR…
The large (X-ray class > M1) and very large (X-ray class >X1) flares (according to the observations of GOES-15 and Preliminary data from Current Catalog of Flare Events) in solar activity cycle 24 were analyzed. The monthly average values…
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,…
Detecting oscillations in solar and stellar time series is complicated by non-stationary red noise and evolving background emission. Methods based on detrending and AR(1)-based wavelet analysis can introduce spurious periodicities and do…
Context. The advent of space-borne missions such as CoRoT or Kepler providing photometric data has brought new possibilities for asteroseismology across the H-R diagram. Solar-like oscillations are now observed in many stars, including red…
The Fourier analysis of the CME occurrence data observed by the SOHO satellite shows significant power around 1.9 yr., 1.2 yr., 265 day, 39 day and 26 day periodicities which are almost similar to the periodicities detected in the Fourier…
Post-flare arcades are well-known components of solar flare evolution, which have been observed for several decades. Coronal rain, cascades of catastrophically-cooled plasma, outline the loops and provide eye-catching evidence of the recent…
We compare the characteristics of flare-accelerated energetic electrons at the Sun with those injected into interplanetary space. We have identified 17 energetic electron events well-observed with the SEPT instrument aboard STEREO which…
Hard x-ray spectral breaks are explained in terms of a 1D model with a co-spatial return current. We study 19 flares observed by RHESSI (Ramaty High Energy Solar Spectroscopic Imager) with strong spectral breaks at energies around a few…
In this work, 1272 superflares on 311 stars are collected from 22,539 solar-type stars from the second-year observation of Transiting Exoplanet Survey Satellite (TESS), which almost covered the northern hemisphere of the sky. Three…
We investigate the flare-frequency distributions of 5 M-dwarfs that experienced superflares with energies in excess of $10^{33}$ erg detected by ASAS-SN. We use K2 and TESS short-cadence observations along with archival ASAS-SN data to…
RHESSI observations of elementary flare bursts are presented. These solar flare elements are distinct emission peaks of a duration of some tens of seconds present in the hard X-ray light curves. They are characterized by consistent…
Variations of frequency separations of low-degree p-modes are studied over the solar activity cycle. The separations studied are obtained from the frequencies of low-degree p-modes of the Global Oscillation Network Group (GONG). 10.7 cm…
The precise physical process that triggers solar flares is not currently understood. Here we attempt to capture the signature of this mechanism in solar image data of various wavelengths and use these signatures to predict flaring activity.…
We report on GROND observations of a 40 sec duration (rest-frame) optical flare from GRB 080129 at redshift 4.349. The rise- and decay time follow a power law with indices +12 and -8, respectively, inconsistent with a reverse shock and a…
X-ray observations of solar flares routinely reveal an impulsive high-energy and a gradual low-energy emission component, whose relationship is one of the key issues of solar flare study. The gradual and impulsive emission components are…