Related papers: Polarized NIR and X-ray Flares from SgrA*
Latest observational data provides evidence that the emissions from Sgr A* originate from an accretion disc within ten gravitational radii of the dynamical centre of Milky Way. We investigate the physical processes responsible for the…
In this work, we studied X-ray source SRGe~J021932.4$-$040154 (SRGe J021932), which we associated with a single X-ray active star of spectral class G2V-G4V and the rotational period $\rm P_{rot} < 9.3$ days. Additional analysis of TESS…
In recent years the case for the presence of 3-4 10^6 M_sun black hole in our Galactic Center has gained strength from results of stellar dynamics observations and from the detection of several rapid X-ray and IR flares observed in the…
We present the first detection from the Spitzer Space Telescope of 4.5 micron variability from Sgr A*, the emitting source associated with the Milky Way's central black hole. The >23 hour continuous light curve was obtained with the IRAC…
On 10 March 2001 the active region NOAA 9368 produced an unusually impulsive solar flare in close proximity to the solar limb. This flare has previously been studied in great detail, with observations classifying it as a type 1 white-light…
GRB 170817A, detected by Fermi-GBM 1.7\,s after the merger of a neutron star (NS) binary, provides the first direct evidence for a link between such a merger and a short-duration gamma-ray burst. The X-ray observations after GRB 170817A…
To understand the correlation and the radiation mechanism of flare emission in different wavelength bands, we have coordinated a number of telescopes to observe SgrA* simultaneously. We focus only on one aspect of the preliminary results of…
We report simultaneous X-ray and infrared (IR) observations of the Galactic microquasar GRS1915+105 using XTE and the Palomar 200-inch telescope on August 13-15, 1997 UTC. During the last two nights, the microquasar GRS 1915+105 exhibited…
Extreme continuum variability in AGNs can indicate extreme changes in accretion flows onto supermassive black holes. We explore the multiwavelength nature of a continuum flare in the Seyfert LCRS B040659.9$-$385922. The all-sky X-ray…
We analyze the gas and dust emission in the immediate vicinity of the supermassive black hole Sgr~A* at the Galactic center (GC) with the ESO VLT (Paranal/Chile) instruments SINFONI and VISIR. The SINFONI H+K data cubes show several…
The supermassive black hole Sagittarius A* (Sgr A*) exhibits temporal and spectral variability across the electromagnetic spectrum. However, variability at radio frequencies below ~ 5 GHz for timescales shorter than a day remains largely…
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.…
Sagittarius A* (Sgr A*) -- the supermassive black hole (SMBH) in the center of our galaxy -- has been observed in most of the electromagnetic spectrum, from radio to X-rays. Diffuse gamma-ray emission has been observed around Sgr A* and a…
We analyze the two brightest Chandra X-ray flares detected from Sagittarius A*, with peak luminosities more than 600 x and 245 x greater than the quiescent X-ray emission. The brightest flare has a distinctive double-peaked morphology ---…
Synchrotron radiation from active galactic nuclei (AGN) is often highly polarized. We present a search for linear polarization with the Very Large Array (VLA) at 4.8 GHz and 8.4 GHz from the nearest AGN, Sagittarius A*. As a part of this…
Sgr A* is variable at radio and submillimeter wavelengths on hourly time scales showing time delays between the peaks of flare emission as well as linearly polarized emission at millimeter and sub-mm wavelengths. To determine the…
The nature of the emission region around Sagittarius A* (Sgr A*), the supermassive black hole at the Galactic Center, remains under debate. A prediction of jet models is that a frequency-dependent shift in the position of the radio core…
Recent near-IR (NIR) and X-ray observations of Sagittarius A*'s spectrum have yielded several strong constraints on the transient energization mechanism, justifying a re-examination of the stochastic acceleration model proposed previously…
Low-luminosity supermassive and stellar-mass black holes (BHs) may be embedded in a collisionless and highly magnetized plasma. They show non-thermal flares indicative of efficient dissipative processes in the vicinity of the BH. During NIR…
We have carried out Very Large Array (VLA) continuum observations to study the variability of Sgr A* at 43 GHz ($\lambda$=7mm) and 22 GHz ($\lambda$=13mm). A low level of flare activity has been detected with a duration of $\sim$ 2 hours at…