We search for highly–ionized gas near three AGN host galaxies using the Chandra low–energy transmission grating spectrograph. Strong absorption lines from such gas are seen at z = 0, most likely from one or more of the following components: (1) a Galactic corona, (2) the Local Group medium, and (3) an extended warm–hot intergalactic medium (WHIM) filament passing through our local overdensity. ...

We simulate the evolution of the intergalactic medium (IGM) in a universe dominated by a cosmological constant. We find that within a few Hubble times from the present epoch, the baryons will have two primary phases: one phase composed of low-density, low-temperature, diffuse, ionized gas which cools rapidly with cosmic time due to adiabatic exponential expansion, and a second phase of high-den...

The first observations of the recently completed Wisconsin H-Alpha Mapper (WHAM) facility include a study of emission lines from high velocity clouds in the M, A, and C complexes, with most of the observations on the M I cloud. We present results including clear detections of Hα emission from all three complexes with intensities ranging from 0.06 to 0.20 R. In every observed direction where the...

We investigate in details the kinematics and morphology of the Seyfert galaxy NGC 6104 in order to identify the mechanism of gas transportation to the active galactic nucleus (AGN). Our observational data were obtained at the 6-m Special Astrophysical Observatory telescope with the MPFS integral-field spectrograph and the SCORPIO universal device in three modes: direct imaging, a scanning Fabry...

Iron Kα emission from photoionized and optically thick material is observed in a variety of astrophysical environments including X-ray binaries, active galactic nuclei, and possibly gamma-ray bursts. This paper presents calculations showing how the equivalent width (EW) of the Fe Kα line depends on the iron abundance of the illuminated gas and its ionization state – two variables subject to sig...

We have considered some results concerning gas and stars kinematics of nearby galaxies recently obtained on the SAO RAS 6m telescope using the panoramic spectroscopy methods. The circumnuclear regions of the galaxies were observed with integral-field spectrograph MPFS. The large-scale ionized gas kinematics was studied with the scanning Fabry-Perot interferometer (FPI) in the multi-mode focal r...

Aims. The expansion of hot ionized gas from an H ii region into a molecular cloud compresses the material and leads to the formation of dense continuous layers as well as pillars and globules in the interaction zone. Herschel imaging in the far-infrared (FIR) confirmed the presence of these dense features – potential sites of star-formation – at the edges of H ii regions. This feedback should a...

Most high-order, harmonic-generation experiments to date have used gas target pressures in excess of 10 Torr. These high pressures have been used to enhance the harmonic signal, which increases quadratically with the pressure. The phase-mismatch factors (caused by both neutral and ionized media) increase with the pressure as does the effect of refraction of the incident laser when the medium be...