Related papers: A Flaring X-ray Source with an Halpha-bright Count…
We report on our discovery and follow-up observations of the X-ray source SAX J1747.0-2853 detected in outburst on 1998, March 10 with the BeppoSAX Wide Field Cameras in the energy range 2-28 keV. The source is located about half degree off…
M dwarfs produce explosive flare emission in the near-UV and optical continuum, and the mechanism responsible for this phenomenon is not well-understood. We present a near-UV/optical flare spectrum from the rise phase of a secondary flare,…
We report on the discovery of a pointlike source (CXOU J160103.1$-$513353) at the center of a Galactic supernova remnant (SNR) G330.2+1.0 with {\it Chandra X-Ray Observatory}. The X-ray spectrum fits a black-body (BB) model with $kT$ $\sim$…
We observed RX J0520.5-6932 in the X-rays and studied the optical light curve of its counterpart to verify it as a Be/X-ray binary. We performed an XMM-Newton anticipated target of opportunity observation in January 2013 during an X-ray…
We report the detection of a dust scattering halo around a recently discovered X-ray transient, Swift J174540.7-290015, which in early February of 2016 underwent one of the brightest outbursts (F_X ~ 5e-10 erg/cm^2/s) observed from a…
The unusually narrow X-ray source imaged with RHESSI during an impulsive spike lasting for $\sim$10~s during the GOES C7.9 flare on 25 September 2011 (SOL2011-09-25T03:32) was only $\sim$2~ arcsec wide and $\sim$10~arcsec long. Comparison…
AX J1845.0-0433 is a transient high-mass X-ray binary discovered by ASCA. The source displays bright and short flares observed recently with INTEGRAL. The transient behaviour and the bright and short flares are studied in order to…
Using XMM-Newton observation, we investigate properties of a flare from the very active and poorly known stellar system 47 Cas. The luminosity at the peak of the flare was found to be 3.54x10^30 erg/s, which is ~2 times more than that at a…
We report on Chandra X-ray and Gemini-North near-infrared K-band observations of the eclipsing accretion-powered millisecond X-ray pulsar SWIFT J1749.4-2807 in quiescence. Using the Chandra observation we derive a source position of Right…
Detection of stellar flares at hard X-ray is still rare at the current stage. A transient was recently detected by the hard X-ray camera, ECLAIRs onboard the SVOM mission at 11:39:01.2UT on 2025, January 09. Simultaneous monitor in the…
In 240 days of X-ray monitoring of M82, we have discovered an X-ray periodicity at $62.0 \pm 2.5$ days with a peak to peak amplitude corresponding to an isotropic luminosity of $2.4 \times 10^{40} \rm erg s^{-1}$ in M82 and an X-ray flare…
Stellar flares affect all atmospheric layers from the photosphere over chromosphere and transition region up into the corona. Simultaneous observations in different spectral bands allow to obtain a comprehensive picture of the environmental…
The new generations of multiwavelength radioheliographs with high spatial resolution will employ microwave imaging spectropolarimetry to recover flare topology and plasma parameters in the flare sources and along the wave propagation paths.…
We report simultaneous observations of the nearby flare star Proxima Centauri with VLT/UVES and XMM-Newton over three nights in March 2009. Our optical and X-ray observations cover the star's quiescent state, as well as its flaring activity…
Archival Chandra observations are used to study the X-ray emission associated with star formation in the central region of the nearby SAB(s)cd galaxy NGC 2403. The distribution of X-ray emission is compared to the morphology visible at…
Daily X-ray flaring represents an enigmatic phenomenon of Sgr A$^{\star}$ --- the supermassive black hole at the center of our Galaxy. We report initial results from a systematic X-ray study of this phenomenon, based on extensive {\it…
We present the results of Chandra X-ray Observatory observations of the transient anomalous X-ray pulsar (AXP) candidate AX J1845.0-0258 in apparent quiescence. Within the source's error circle, we find a point source and possible…
Dynamics of hot chromospheric plasma of solar flares is a key to understanding of mechanisms of flare energy release and particle acceleration. A moderate M1.0 class flare of 12 June, 2014 (SOL2014-06-12T21:12) was simultaneously observed…
Using the XMM-Newton X-ray observatory to monitor the nearest star to the Sun, Proxima Centauri, we recorded the weakest X-ray flares on a magnetically active star ever observed. Correlated X-ray and optical variability provide strong…
We have discovered an x-ray source, SAX J0635+0533, with a hard spectrum within the error box of the GeV gamma-ray source in Monoceros, 2EG J0635+0521. The unabsorbed x-ray flux is 1.2*10^-11 erg cm^-2 s^-1 in the 2-10 keV band. The x-ray…