We present a new, high resolution HST/GHRS spectrum of quasar Q0302003, and use the He Lyman-α absorption, together with a high resolution Keck spectrum of the HI Lyman-α forest, to probe the distribution and ionization state of foreground gas just below the quasar redshift z ≈ 3.3. Within ≈ 4000 km/sec of the quasar redshift the spectrum shows a substantial flux (τ ≈ 1) with “He Lyman-α forest...

Monitoring of free gas embedded in scattering media, such as wood, fruits, and synthetic materials, is demonstrated by use of diode laser spectroscopy combined with sensitive modulation techniques. Gas detection is made possible by the contrast of the narrow absorptive feature of the free-gas molecules with the slow wavelength dependence of the absorption and scattering cross sections in solids...

We present an extended analysis of the high dispersion IUE spectra of SN 1993J in M 81, based on the improved data in the IUE final archive. Eight interstellar absorption components can be identified in the velocity range from −200 km s to +200 km s. Column densities are determined for Fe II, Mg I, Mg II, O I, S II, Si II, and Zn II. From the ion ratios, we estimate electron densities and tempe...

High-accuracy spectral-slit-function calibration measurements, in situ ambient absorption gas cell measurements for ozone and nitrogen dioxide, and ground-based zenith sky measurements with the Earth Observing System Aura Ozone Monitoring Instrument (OMI) flight instrument are reported and the results discussed. For use of high-spectral-resolution gas absorption cross sections from the literatu...

In order to discuss the atomization process of an analyte element occurring in a graphite furnace for atomic absorption spectrometry, we measured variations in the characteristic temperature with the progress of an atomization stage, by using a two-line method under the assumption of a Boltzmann distribution. For this purpose, iron was chosen as the analyte element. Also, the atomic absorption ...

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. ...

Centaurus A, the nearest AGN shows molecular absorption in the millimeter and radio regime. By observing the absorption with VLBI, we try to constrain the distribution of the gas, in particular whether it resides in the circumnuclear region. Analysis of VLBA observations in four OH and two H2CO transitions is presented here, as well as molecular excitation models parameterized with distance fro...

We report the detection of broad (FWHM 270kms 1) H I 21 cm absorption toward the compact (<15h 1 pc) radio nucleus of the nearby powerful radio galaxy Cygnus A. The absorption corresponds to a column density of hydrogen atoms of at least 2.54 0.44 1019 Tspin cm 2. Observations of OH and H2CO yielded upper limits. While other possibilities exist, we argue that the observed H I absorption plausib...

We report the detection of broad (FWHM 270 km s) H I z 21 cm absorption toward the compact (,15 h pc) radio nucleus of the nearby powerful radio galaxy Cygnus A. The absorption corresponds to a column density of hydrogen atoms of at least 2.54H 0.44 3 10 Tspin cm. Observations of OH and H2CO yielded upper limits. While other possibilities exist, we argue that the observed H I absorption plausib...