Related papers: Partial Coverage and Time Variability of Narrow-Li…
We establish a simple model for the distribution of cold gas around L* galaxies using a large set of observational constraints on the properties of strong MgII absorber systems. Our analysis suggests that the halos of L* galaxies are filled…
Studies of high resolution quasar absorption lines (QALs), arising from gas in local and z < 1.5 galaxies, provide direct probes of the kinematic, chemical, and ionization conditions and evolution of Milky Way-like galaxies. Inferences…
The large observed redshift of quasars has suggested large cosmological distances and a corresponding enormous energy output to explain the brightness or luminosity as seen at earth. Alternative or complementary sources of redshift have not…
We make a distinction between the spectroscopic and the mesoscopic conductance of closed systems. We show that the latter is not simply related to the Landauer conductance of the corresponding open system. A new ingredient in the theory is…
We investigate the properties of the circumgalactic gas in the halo of quasar host galaxies from CIV absorption line systems. Optical spectroscopy of closely aligned pairs of quasars (projected distance \leq 200 kpc) obtained at the Gran…
Correlations between BAL QSO intrinsic properties and polarization have been searched for. Some results are summarized here, providing possible constraints on BAL outflow models.
The presence of clouds between an airshower and a space-based detector can dramatically alter the measured signal characteristics due to absorption and scattering of the photonic signals. Furthermore, knowledge of the cloud cover in the…
We wish to study the extent and subparsec scale spatial structure of intervening quasar absorbers, mainly those involving neutral and molecular gas. We have selected quasar absorption systems with high spectral resolution and good S/N data,…
We examine a model for the variable free-free and neutral hydrogen absorption inferred towards the cores of some compact radio galaxies in which a spatially fluctuating medium drifts in front of the source. We relate the absorption-induced…
We explore the connection between absorption by neutral gas and extinction by dust in mid-infrared (IR) selected luminous quasars. We use a sample of 33 quasars at redshifts 0.7 < z < 3 in the 9 deg^2 Bo\"otes multiwavelength survey field…
We present optical spectroscopy of projected QSO pairs to investigate the MgII and the CIV absorption features imprinted on the spectrum of the background object by the gaseous halo surrounding the foreground QSO. We observed 13 projected…
High resolution spectra of quasar absorption systems provide the best constraints on temporal or spatial changes of fundamental constants in the early universe. An important systematic that has never before been quantified concerns model…
A detailed study of the absorbing molecular clouds towards the radio source PKS1413+135, at a redshift z=0.247, is reported. Physical conditions are derived for the molecular gas in the frame work of two models: a homogeneous multicomponent…
Quasar absorption lines have long been recognized to be a sensitive probe of the abundances, physical conditions, and kinematics of gas in a wide variety of environments including low-density intergalactic regions that probably cannot be…
We perform a systematic study of physical properties and distribution of neutral and ionised gas in the halo of the Milky Way (MW). Beside the large neutral intermediate- and high-velocity cloud (IVC, HVC) complexes there exists a…
We discuss the identification and kinematics of intrinsic narrow-line absorbers in three QSOs. The line-of-sight ejection velocities in the confirmed intrinsic systems range from 1500 to 51,000 km/s. The ratio of ejection velocity to line…
We develop the quantum hydrodynamics of inner waves in the bulk of fractional quantum Hall states. We show that the inelastic light scattering by inner waves is a sole effect of the gravitational anomaly. We obtain the formula for the…
Line locking (LL) of absorption line systems is a clear signature of the dynamical importance of radiation pressure force in driving astrophysical flows, with recent findings suggesting that it may be common in quasars exhibiting multiple…
We propose a model of quasar lifetimes in which observational quasar lifetimes and an intrinsic lifetime of rapid accretion are strongly distinguished by the physics of obscuration by surrounding gas and dust. Quasars are powered by gas…
We investigate the limits of intracavity absorption spectroscopy with nonlinear media. Using a common theoretical framework, we compare the detection of a trace gas within an undriven cavity with gain near and above threshold, a driven…