Related papers: FUSE Observations of Diffuse Interstellar Molecula…
We present an extinction analysis of 9 paths through the LMC and SMC based on FUSE observations. To date, just two LMC sight lines have probed dust grain composition and size distributions in the Clouds using spectra including wavelengths…
There is mounting evidence for an extra-planar gas layer around the Milky Way disk, similar to the anomalous HI gas detected in a few other galaxies. As much as 10% of the gas may be in this phase. We analyze HI clouds located in the…
We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…
We present measurements of interstellar H_2 absorption lines in the continuum spectra of seven early-type stars in the Galactic disk at distances between 1 and 4 kpc. Five of these stars provide lines of sight through the Sagittarius spiral…
We used the Plateau de Bure Interferometer to search for $\lambda$3mm absorption lines of HOC+ from local diffuse and translucent clouds occulting compact extragalactic mm-wave continuum sources. We detected HOC+ in three directions with…
We present ISO observations of several H2 pure-rotational lines (from S(0) to S(5)) towards a sample of 16 molecular clouds distributed along the central ~ 500 pc of the Galaxy. We also present C18O and 13CO J=1->0 and J=2->1 observations…
We present a comprehensive study of the excitation of CI fine-structure levels along 57 sight lines in the Large and Small Magellanic Clouds. The sight lines were selected by the detection of H$_2$ in FUSE spectra. Using archival HST/COS…
Spectra of about 150 early-type stars in the disk of the Milky Way recorded by the Far Ultraviolet Spectroscopic Explorer (FUSE) reveal absorption features from interstellar O VI, a tracer of collisionally ionized gases at temperatures near…
Lyman- and Werner-band absorption of molecular hydrogen (H$_2$) is detected in $\sim$50% of low redshift ($z<1$) DLAs/sub-DLAs with $N$(H$_2$) > 10$^{14.4}$ cm$^{-2}$. However the true origin(s) of the H$_2$ bearing gas remain elusive. Here…
We review here the main direct or indirect ways to detect the possible presence of large amounts of cold molecular hydrogen in the outer parts of disk galaxies, an hypothesis that we have recently developed. Direct ways range from H2…
There is a robust polyatomic chemistry in diffuse, partially-molecular interstellar gas that is readily accessible in absorption at radio/mm/sub-mm wavelengths. Accurate column densities are derived owing to the weak internal excitation, so…
We present a study of the abundances and physical conditions in the interstellar gas toward the heavily reddened star HD 192639 [E_(B-V) = 0.64], based on analysis of FUSE and HST/STIS spectra covering the range from 912 to 1361 A. This…
We present an analysis of archival ISO observations of pure-rotational lines of H2 in three pointings in the central 3 parsecs of the Galaxy: toward the Southwest region and Northeast region of the Galactic center Circumnuclear Disk, and…
In this paper, we present new data with interstellar C2 (Phillips bands A-X), from observations made with the Ultraviolet-Visual Echelle Spectrograph of the European Southern Observatory. We have determined the interstellar column densities…
We know little about the outermost portions of galaxies because there is little light coming from them. We do know that in many cases atomic hydrogen (HI) extends well beyond the optical radius \cite{Casertano91}. In the centers of…
The FUSE far-ultraviolet interstellar spectra toward seven targets in NGC 6231 show that the molecules H_2, HD, and CO as well as various atomic species are distributed in several clouds. The main absorption component found on the sight…
More than 20 years after the Copernicus satellite, ORFEUS allows the investigation of molecular hydrogen (H_2) in the diffuse interstellar medium by way of FUV absorption spectroscopy once again. This time, targets in the Magellanic Clouds…
We discuss physical conditions in Galactic neutral hydrogen based on deep, high velocity resolution interferometric HI 21 cm absorption spectroscopy towards 33 compact extra-galactic radio sources. The HI 21 cm optical depth spectra have…
The {\it Far Ultraviolet Spectroscopic Explorer} ({\it FUSE}) has allowed precise determinations of the column densities of molecular hydrogen ($\Hmol$) in Galactic lines of sight with a wide range of pathlengths and extinction properties.…
We present the results of a FUSE survey of O VI 1031.93 Angstrom and 1037.62 Angstrom absorption toward 18 OB stars in the Small Magellanic Cloud (SMC). We detect O VI along every sight line. The average value of the O VI column density in…