Related papers: A Model for Anisotropic Interstellar Scattering an…
The atmospheres of planets (including Earth) and the outer layers of stars have often been treated in radiative transfer as plane-parallel media, instead of spherical shells, which can lead to inaccuracy, e.g. limb darkening. We give an…
The Milky Way's satellite galaxies and Globular Clusters (GCs) are known to exhibit an anisotropic spatial distribution. We examine in detail this anisotropy by the means of the inertia tensor. We estimate the statistical significance of…
The detection of a mm/Sub-mm ``bump'' in Sgr A*'s radio spectrum suggests that at least a portion of its overall emission is produced within a compact accretion torus. This inference is strengthened by observations of strong linear…
The Galaxy's supermassive black hole, Sgr A*, produces an outburst of infrared radiation about once every 6 hours, sometimes accompanied by an even more energetic flurry of X-rays. The NIR photons are produced by nonthermal synchrotron…
Spectral and kinematic studies suggest that the nonthermal radio source Sgr A*, located at the center of the Milky Way, is a supermassive compact object with a mass 2-3 million solar masses. Winds from nearby stars, located approximately…
We analyze a merged Parker Solar Probe ($PSP$) and Solar Orbiter ($SO$) dataset covering heliocentric distances $13 \ R_{\odot} \lesssim R \lesssim 220$ $R_{\odot}$ to investigate the radial evolution of power and spectral-index anisotropy…
We calculate the scattering of X-rays by interstellar dust, for a dust model that reproduces the observed wavelength-dependent extinction and polarization of starlight. On interstellar sightlines that produce appreciable starlight…
The slow particle diffusion in pulsar halos, inferred from TeV gamma-ray surface brightness profiles, is attributed to cross-field diffusion under the anisotropic diffusion model. This model assumes sub-Alfv\'enic interstellar turbulence in…
We develop the theory of interstellar scintillation as caused by an irregular plasma having a power-law spatial density spectrum with a spectral exponent of 4 corresponding to a medium with abrupt changes in its density. An ``outer scale''…
Observations of Sagittarius A* (Sgr A*) in near-infrared (NIR) show irregular flaring activity. Flares coincide with astrometric rotation of brightness centroid and with looping patterns in fractional linear polarization. These signatures…
Sgr A* is considered to be a massive black hole at the Galactic center and is known to be variable in radio, millimeter, near-IR and X-rays. Recent multi-wavelength observing campaigns show a simultaneous X-ray and near-IR flare, as well as…
We discuss the composition of dust and ice along the line of sight to the Galactic Center (GC) based on analysis of mid-infrared spectra (2.4-13 micron) from the Short Wavelength Spectrometer on the Infrared Space Observatory (ISO). We have…
By solving radiative transfer equations, we examine three-dimensional radiative properties of a magnetohydrodynamic accretion flow model confronting with the observed spectrum of Sgr A*, in the vicinity of supermassive black hole at the…
Although it is widely accepted that most galaxies have supermassive black holes (SMBHs) at their centers^{1-3}, concrete proof has proved elusive. Sagittarius A* (Sgr A*)^4, an extremely compact radio source at the center of our Galaxy, is…
We present models of Galactic Center emission in the vicinity of Sagittarius A* that use parametrizations of the electron temperature or energy density. These models include those inspired by two-temperature general relativistic…
The multiple scattering of scalar waves in diffusive media is investigated by means of the radiative transfer equation. This approach amounts to a resummation of the ladder diagrams of the Born series; it does not rely on the diffusion…
We study the scattering of low-energy Cosmic Rays (CRs) in a turbulent, compressive MHD fluid. We show that compressible MHD modes -- fast or slow waves with wave lengths smaller than CR mean free paths induce cyclotron instability in CRs.…
We measure the anisotropy of dark matter flows on small scales in the near environment of haloes using a large set of simulations. We rely on two different approaches to quantify the anisotropy of the cosmic infall: we measure the flows at…
Sagittarius A* is the source of near infrared, X-ray, radio, and (sub)millimeter emission associated with the supermassive black hole at the Galactic Center. In the submillimeter regime, Sgr A* exhibits time-variable linear polarization on…
Sgr A* is an ideal target to study low-luminosity accreting systems. It has been recently proposed that properties of the accretion flow around Sgr A* can be probed through its interactions with the stellar wind of nearby massive stars…