Related papers: Highly Ionized High Velocity Clouds
Recent spectroscopic observations of intermediate- and high-velocity clouds (IVCs and HVCs) in the Milky Way halo have unveiled the presence of diffuse interstellar molecular hydrogen (H_2) several kpc away from the Galactic disk. Most of…
Six examples of the compact, isolated high-velocity clouds catalogued by Braun & Burton (1999) and identified with a dynamically cold ensemble of primitive objects falling towards the barycenter of the Local Group have been imaged with the…
We employ three-band Spitzer-MIPS observations to search for cold dust emission in three neutral hydrogen compact high-velocity clouds (CHVCs) in the vicinity of the Milky Way. Far-infrared emission correlated with HI column density was…
We investigate the impact of environment on the metallicity of the diffuse intergalactic medium. We use pixel correlation techniques to search for weak CIV and OVI absorption in the spectrum of quasar Q1422+231 in regions of the spectrum…
We present the current distance estimates to 11 intermediate velocity clouds (IVCs) which are part of the David Dunlap Observatory Intermediate Velocity Cloud (DDO IVC) Distance Project (Clarke et al. 1999). We briefly discuss constraints…
Using high-resolution ultraviolet spectra obtained with the HST/Space Telescope Imaging Spectrograph (STIS) and the Far Ultraviolet Spectroscopic Explorer, we study the metallicity, kinematics, and distance of the gaseous "Outer Arm" (OA)…
We analyze high-resolution UV spectra of the Mg II h and k lines for 18 members of the Hyades Cluster to study inhomogeneity along these proximate lines of sight. The observations were taken by the Space Telescope Imaging Spectrograph…
We present an analysis of the complex associated system of the high-redshift QSO HE2347-4342. Absorption features of HI, CIII, CIV, NV, and OVI with up to 16 components occur in the optical spectral range located up to 1500 km/s redwards…
Metal absorption systems are products of star formation. They are believed to be associated with massive star forming galaxies, which have significantly enriched their surroundings. To test this idea with high column density CIV absorption…
The composition and physical properties of several local clouds, including the Local Interstellar Cloud (LIC) in which the Sun is embedded, are derived from absorption features in the UV spectrum of the star epsilon CMa. We derive…
We study the clustering properties of metals in the intergalactic medium (IGM) as traced by 619 CIV, 81 SiIV, N >= 10^12 cm^-2 and 316 MgII, and 82 FeII N >= 10^11.5 cm^-2 absorption components in 19 high signal-to-noise (60-100 per pixel),…
Very sensitive HI 21cm observations have been made in 860 directions at dec >= -43deg in search of weak, Galactic, high-velocity HI emission lines at moderate and high Galactic latitudes. One-third of the observations were made toward…
We present the germ of a new model for High Velocity Clouds, derived from the idea that the dark matter halo of our Galaxy is in the form of cold, planetary-mass gas clouds. In this picture HVCs arise as a result of disruptive collisions…
We examine the fine structure lines $^{3}P_{1}\to $$^{3}P_{0}$ (492 GHz) and $ ^{3}P_2\to $$^{3}P_1$ (809 GHz) of neutral atomic carbon as bulk molecular gas mass tracers and find that they can be good and on many occasions better than $…
To characterize the absorption properties of this circumgalactic medium (CGM) and its relation to the LG we present the so-far largest survey of metal absorption in Galactic high-velocity clouds (HVCs) using archival ultraviolet (UV)…
We present two sets of grid-based hydrodynamical simulations of high-velocity clouds (HVCs) traveling through the diffuse, hot Galactic halo. These HI clouds have been suggested to provide fuel for ongoing star formation in the Galactic…
We explore theoretical models of the ionization ratios of the Li-like absorbers NV, OVI, and CIV, in the Galactic halo. These ions are believed to form in nonequilibrium processes such as shocks, evaporative interfaces, or rapidly cooling…
We present a detailed analysis of a very unusual sub-damped Lyman alpha (sub-DLA) system at redshift z=2.304 towards the quasar Q0453-423, based on high signal-to-noise (S/N), high-resolution spectral data obtained with VLT/UVES. With a…
We present new H I 21 cm absorption data and ultraviolet spectroscopy from HST/STIS of the QSO/galaxy pair 3C 232/NGC 3067. The QSO sightline lies near the minor axis and 1.8 arcmin (11 kpc) above the plane of NGC 3067, a nearby luminous…
We have analyzed the properties of metals in the high redshift intergalactic medium using a novel objective pixel optical depth technique on a sample of extremely high signal-to-noise Keck HIRES and ESI spectra of 26 quasars between…