Related papers: Flares from plasmoids and current sheets around Sg…
The Galactic Center black hole Sgr A* shows significant variability and flares in the submillimeter, infrared, and X-ray wavelengths. Owing to its exquisite resolution in the IR bands, the GRAVITY experiment for the first time spatially…
Sgr A* exhibits flares in the near-infrared and X-ray bands, with the luminosity in these bands increasing by factors of $10-100$ for $\approx 60$ minutes. One of the models proposed to explain these flares is synchrotron emission of…
Hot spots, or plasmoids, forming due to magnetic reconnection in current sheets, are conjectured to power frequent X-ray and near-infrared flares from Sgr A*, the black hole in the center of our Galaxy. It is unclear how, where, and when…
Sgr A*, the supermassive black hole (SMBH) at the center of our Milky Way Galaxy, is known to be a variable source of X-ray, near-infrared (NIR), and submillimeter (submm) radiation and therefore a prime candidate to study the…
Large-amplitude Sgr A* near-infrared flares result from energy injection into electrons near the black hole event horizon. Astrometry data show continuous rotation of the emission region during bright flares, and corresponding rotation of…
(Abridged) Sgr A$^\star$ is the electromagnetic counterpart of the accreting supermassive black hole in the Galactic center. Its emission is variable in the near-infrared (NIR) and X-ray wavelengths on short timescales. The physical origin…
Our central Galactic supermassive black hole, Sgr A*, exists mostly in a very stable, extremely low-luminosity (~10^{-9} L_Edd), thermal quiescent state, which is interrupted roughly daily by a brief, nonthermal X-ray flare. Because they…
Sagittarius~A$^*$, the supermassive black hole at the center of our galaxy, exhibits flares across various wavelengths, yet their origins remain elusive. We performed 3D two-temperature General Relativistic Magnetohydrodynamic (GRMHD)…
High-resolution observations with GRAVITY-VLTI instrument have provided abundant information about the flares in Sgr A*, the supermassive black hole in our Galactic center, including the time-dependent location of the centroid (a "hot…
Magnetic reconnection can power bright, rapid flares originating from the inner magnetosphere of accreting black holes. We conduct extremely high resolution ($5376\times2304\times2304$ cells) general-relativistic magnetohydrodynamics…
Flares from the supermassive black hole in our Galaxy, Sagittarius~A$^\star$ (Sgr A$^\star$), are routinely observed over the last decade or so. Despite numerous observational and theoretical efforts, the nature of such flares still remains…
Sagittarius A*, the supermassive black hole at the center of our galaxy, exhibits episodic near-infrared flares. The recent monitoring of three such events by the GRAVITY instrument has shown that some flares are associated with orbital…
Recent observations of SgrA* by the GRAVITY instrument have astrometrically tracked infrared flares (IR) at distances of $\sim 10$ gravitational radii ($r_g$). In this paper, we study a model for the flares based on 3D general relativistic…
Context: The origin of ultra-rapid flares of very high-energy radiation from active galactic nuclei remains elusive. Magnetospheric processes, occurring in the close vicinity of the central black hole, could account for these flares. Aims:…
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…
Recent infrared (IR) observations of the center of our Galaxy indicate that the supermassive black hole source Sgr A* is strongly variable in the IR. The timescale for the variability, $\sim 30$ min, is comparable to that of the X-ray…
In general relativistic magneto-hydrodynamic (GRMHD) simulations, accreted magnetic flux on the black hole horizon episodically decays, during which magnetic reconnection heats up the plasma near the horizon, potentially powering…
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…
Observations of bright and variable "reflected" X-ray emission from molecular clouds located within inner hundred parsec of our Galaxy have demonstrated that the central supermassive black hole, Sgr A*, experienced short and powerful flares…
Sgr A*, the massive black hole at the center of the Galaxy, varies in radio through X-ray emission on hourly time scales. The flare activity is thought to arise from the innermost region of an accretion flow onto Sgr A*. We present…