Related papers: Resolving Two Distinct Thermal X-ray Components in…
The Neutron star Interior Composition ExploreR (NICER) X-ray observatory observed two powerful X-ray flares equivalent to superflares from the nearby young solar-like star, kappa1 Ceti, in 2019. NICER follows each flare from the onset…
The X-ray and near-IR emission from Sgr A* is dominated by flaring, while a quiescent component dominates the emission at radio and sub-mm wavelengths. The spectral energy distribution of the quiescent emission from Sgr A* peaks at sub-mm…
The hard X-ray (HXR) emission in solar flares comes almost exclusively from a very small part of the flaring region, the footpoints of magnetic loops. Using RHESSI observations of solar flare footpoints, we determine the radial positions…
Cool stars are known to produce flares probably as a result of magnetic reconnection in their outer atmospheres. We present simultaneous XMM-Newton optical V band and X-ray observations of the M8 dwarf LP412-31. During the observation a…
The feature of quasi-periodic pulsations (QPPs) is frequently observed in the light curve of solar and stellar flares. In this letter, we investigated the QPP at a shorter period in high-energy channels of HXRs and Ggamma-ray continuum…
X-rays are a valuable diagnostic tool for the study of high energy accelerated electrons. Bremsstrahlung X-rays produced by, and directly related to, high energy electrons accelerated during a flare, provide a powerful diagnostic tool for…
Solar flares exhibit complex variations in elemental abundances compared to photospheric values. We examine the spatial and temporal evolution of coronal abundances in the X8.2 flare on 2017 September 10, aiming to interpret the often…
Using RHESSI and some auxiliary observations we examine possible connections between spatial and temporal morphology of the sources of non-thermal hard X-ray (HXR) emission which revealed minute quasi-periodic pulsations (QPPs) during the…
A common feature of electromagnetic emission from solar flares is the presence of intensity pulsations that vary as a function of time. Known as quasi-periodic pulsations (QPPs), these variations in flux appear to include periodic…
The aim of the thesis is the study of properties of solar flares via reconstruction of energy distributions of accelerated/heated electrons, diagnostics of flare plasma based on EUV and X-ray observations, as well as the estimation of the…
Solar flares are sudden energy release events in the solar corona, resulting from magnetic reconnection, that accelerates particles and heats the ambient plasma. During a flare, there are often multiple, temporally and spatially separated…
Abridged. We observed the 40 Myr old star DS Tuc A with XMM-Newton and recorded two X-ray bright flares, with the second event occurring about 12 ks after the first one. Their duration from the rise to the end of the decay was of about 8-10…
Particle acceleration is one of the most significant features that are ubiquitous among space and cosmic plasmas. It is most prominent during flares in the case of the Sun, with which huge amount of electromagnetic radiation and high-energy…
There are still debates whether particle acceleration in solar flares may occur due to interruption of electric currents flowing along magnetic loops. To contribute to this problem, we performed the first statistical study of relationships…
Typical solar flares display two quasi-parallel, bright ribbons on the chromosphere. In between is the polarity inversion line (PIL) separating concentrated magnetic fluxes of opposite polarity in active regions (ARs). Intriguingly a series…
Recent observations in extreme-ultraviolet (EUV) wavelengths reveal an EUV late phase in some solar flares, which is characterized by a second peak in the warm coronal emissions (about 3 MK) occurring several tens of minutes to a few hours…
Nonthermal sources located above bright flare arcades, referred to as the "above-the-loop-top" sources, have been often suggested as the primary electron acceleration site in major solar flares. The X8.2 limb flare on 2017 September 10…
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…
Identifying the source of the material within coronal mass ejections (CMEs) and understanding CME onset mechanisms are fundamental issues in solar and space physics. Parameters relating to plasma composition, such as charge states and He…
With increasing solar activity since 2010, many flares from the backside of the Sun have been observed by the Extreme Ultraviolet Imager (EUVI) on either of the twin STEREO spacecraft. Our objective is to estimate their X-ray peak fluxes…