Related papers: White Light Flare Continuum Observations with ULTR…

Three periastron passages of the PSR B1259$-$63/LS 2883 binary system, consisting of a 48 ms rotation-powered pulsar and a $\sim30$ M$_{\odot}$ Be star, have been observed by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space…

Quasi-Periodic Erupters (QPEs) are a remarkable class of objects exhibiting very large amplitude quasi-periodic X-ray flares. Although numerous dynamical models have been proposed to explain them, relatively little attention has been given…

Large, complex, active regions may produce multiple flares within a certain period of one or two days. These flares could occur in the same location with similar morphologies, commonly referred to as homologous flares. In 2011 September,…

Young solar-type stars frequently produce superflares, serving as a unique window into the young Sun-Earth environments. Large solar flares are closely linked to coronal mass ejections (CMEs) associated with filament/prominence eruptions,…

Quasi-periodic pulsations (QPPs), which usually appear as temporal pulsations of the total flux, are frequently detected in the light curves of solar/stellar flares. In this study, we present the investigation of non-stationary QPPs with…

Flares are intense explosions on the solar and stellar surfaces, and solar flares are sometimes accompanied by filament or prominence eruptions. Recently, a large filament eruption associated with a superflare on a solar-type star EK Dra…

We present the X-ray quiescent and flaring properties from a unique, 7-day multiwavelength observing campaign on the M1 flare star AU Mic. Combining the XMM-Newton X-ray spectra with the chromospheric line and broadband NUV and optical…

Spectroscopic observations covering the wavelength range 3600--4600\AA are presented for a large flare on the late type M dwarf AT Mic (dM4.5e). A procedure to estimate the physical parameters of the flaring plasma has been used which…

The radio, optical, and $\gamma$-ray light curves of the blazar S5 1803+784, from the beginning of the {\it Fermi} Large Area Telescope (LAT) mission in August 2008 until December 2018, are presented. The aim of this work is to look for…

Black phosphorus is a quasi-two-dimensional layered semiconductor with a narrow direct band gap of 0.3 eV. A giant surface Stark effect can be produced by the potassium doping of black phosphorus, leading to a semiconductor to semimetal…

Flares and CMEs are very powerful events in which energetic radiation and particles are ejected within a short time. These events thus can strongly affect planets that orbit these stars. This is particularly relevant for planets of M-stars,…

Extreme helium stars (EHe stars) are hydrogen-deficient supergiants of spectral type A and B. They are believed to result from mergers in double degenerate systems. In this paper we present a detailed quantitative non-LTE spectral analysis…

Using archival SDSS multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by super-massive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. They have optical…

We discovered Fe $K_{\alpha}$ complex emission and pulsation in two highly variable sources (4XMM J174917.7--283329, 4XMM J174954.6--294336). The equivalent widths of 6.4 and 6.7 keV lines of 4XMM J174917.7--283329 are $99^{+84}_{-72}$ and…

White-light flares (WLFs) are crucial for understanding the energy transport and heating processes in the lower solar atmosphere. Systematic studies are highly necessary. However, most WLFs are very weak and difficult to detect. To address…

This paper reports the ULTRACAM discovery of dipolar surface spots in two cool magnetic white dwarfs with Balmer emission lines, while a third system exhibits a single spot, similar to the prototype GD 356. The light curves are modeled with…

In this paper, we report the detection and follow-ups of a super stellar flare GWAC\,181229A with an amplitude of $\Delta R\sim$9.5 mag on a M9 type star by $\text{SVOM/GWAC}$ and the dedicated follow-up telescopes. The estimated bolometric…

Solar white-light flares (WLFs) are solar flares exhibiting enhanced emission in the optical continuum. They are critical for understanding energy release and transport mechanisms in solar flares and for conducting comparative studies with…

We report on the analysis of a long XMM-Newton EPIC observation in 2001 May of the Narrow Line Seyfert 1 galaxy Mkn 766. The 3-11 keV spectrum exhibits a moderately steep power law continuum, with a broad emission line at ~6.7 keV, probably…

Stellar flares are an intense stellar activity that can significantly impact the atmospheric composition of the surrounding planets and even the possible existence of life. During such events, the radiative energy of the star is primarily…