相关论文: Variability in Active Galactic Nuclei from Propaga…
Dynamic fluctuations in the local density of non-identified hadron tracks reconstructed in the STAR TPC are studied using the discrete wavelet transform power spectrum technique which involves mixed event reference sample comparison. The…
The X-ray emission from the jets in Active Galactic Nuclei (AGN) carries important information on the distributions of relativistic electrons and magnetic fields on large scales. We reanalyze archival Chandra observations on the jet of M87…
The unified model of active galactic nuclei (AGN) includes a toroidal obscuring structure to explain the differences between Type I and Type II AGN as an effect of inclination angle. This toroidal structure is thought to be 'clumpy' as the…
The multivariate tool of Principal Component Analysis (PCA) is applied to 23 fields in the FCRAO CO Survey of the Outer Galaxy. PCA enables the identification of line profile differences which are assumed to be generated from fluctuations…
Relativistic magnetically dominated turbulence is an efficient engine for particle acceleration in a collisionless plasma. Ultrarelativistic particles accelerated by interactions with turbulent fluctuations form non-thermal power-law…
To investigate the differences in mechanical feedback from radio-loud and radio-quiet Active Galactic Nuclei (AGN) on the host galaxy, we perform 3D AMR hydrodynamic simulations of wide angle, radio-quiet winds with different inclinations…
Three-dimensional (3D) hydrodynamic simulations of shell oxygen burning (Meakin and Arnett, 2007b) exhibit bursty, recurrent fluctuations in turbulent kinetic energy. These are shown to be due to a general instability of the convective…
Turbulent motions due to flux-driven thermal convection is investigated by numerical simulations and stochastic modelling. Tilting of convection cells leads to the formation of sheared flows and quasi-periodic relaxation oscillations for…
The observed variability of X-ray binaries over a wide range of time-scales can be understood in the framework of a stochastic propagation model, where viscous fluctuations at different radii induce accretion rate variability that propagate…
Non-spherical explosions develop non-radial flows as the pattern of shock emergence progresses across the stellar surface. In supernovae these flows can limit ejecta speeds, stifle shock breakout emission, and cause collisions outside the…
The hierarchical formation of clusters of galaxies by accretion of material releases gravitational energy which dissipates into the intracluster gas. The process heats the material and generates gas turbulence and bulk motions and thus…
We discuss about how the relative flux densities among the images of gravitationally-lensed active galactic nuclei, AGN, can be used to study the intrinsic AGN variability with high accuracy. Multi-frequency monitoring observations of…
An increasing number of Active Galactic Nuclei (AGNs) exhibit broad, double-peaked Balmer emission lines,which represent some of the best evidence for the existence of relatively large-scale accretion disks in AGNs. A set of 20…
We compared optical spectroscopic and photometric data for 18 AGN galaxies over 2 to 3 epochs, with time intervals of typically 5 to 10 years. We used the Multi-Object Double Spectrograph (MODS) at the Large Binocular Telescope (LBT) and…
The evolution of buoyancy-driven homogeneous variable-density turbulence (HVDT) at Atwood numbers up to 0.75 and large Reynolds numbers is studied by using high-resolution Direct Numerical Simulations. To help understand the highly…
Turbulence is a key element of the dynamics of astrophysical fluids, including those of interstellar medium, clusters of galaxies and circumstellar regions. Turbulent motions induce Doppler shifts of observable emission and absorption…
The author is developing a numerical code with thousands of emission zones to simulate the time-dependent multi-waveband emission from blazars. The code is based on a model in which turbulent plasma flowing at a relativistic speed down a…
Fluxes emitted at different wavebands from active galactic nuclei (AGNs) fluctuate at both long and short timescales. The variation can typically be characterized by a broadband power spectrum, which exhibits a red-noise process at high…
Observations indicate that turbulent motions are present on most massive star surfaces. Starting from the observed phenomena of spectral lines with widths much larger than thermal broadening (e.g. micro- and macroturbulence) to the…
Density waves excited by planets embedded in protoplanetary disks play a central role in planetary migration and gap opening processes. We carry out 2D shearing sheet simulations to study the linear regime of wave evolution with the…