Related papers: Vacuum-UV absorption spectroscopy of interstellar …
We present a study of the intrinsic absorption lines in the ultraviolet spectra of Seyfert 1 galaxies. We find that the fraction of Seyfert 1 galaxies that show absorption associated with their active nuclei is more than one-half (10/17),…
We present results from a coordinated IR-to-X-ray spectral campaign of the QSO IRAS 13349+2438. Optical spectra reveal extreme Eigenvector-1 characteristics, but the H-beta line width argues against a NLS1 classification; we refine…
Photon-stimulated desorption (PSD) is a process of interest for the two seemingly unrelated topics of accelerator vacuum dynamics and astrochemistry. Here we present an approach to studying PSD of interstellar ice analogs, i.e. condensed…
The total amount of OVI present in the interstellar medium (ISM) obtained via absorption measurements in UV and X-ray spectra is currently in disagreement, with the latter being significantly larger (by a factor of 10 or more) than the…
We examine 20 diffuse and translucent Galactic sight lines and extract the column densities of the ^12CO and ^13CO isotopologues from their ultraviolet A--X absorption bands detected in archival Space Telescope Imaging Spectrograph data…
The goal of the present paper is to investigate the circumstellar material around the brightest dust-enshrouded sources in the central stellar cluster of the Milky Way. Observations have been carried out at the European Southern…
We analyze high-resolution spectra obtained with the Space Telescope Imaging Spectrograph onboard the Hubble Space Telescope toward 34 nearby stars (<100 pc) to record MgII, FeII and MnII absorption due to the local interstellar medium…
Absorption of ultraviolet radiation by water ice coating interstellar grains can lead to dissociation and desorption of the ice molecules. These processes are thought to be important in the gas-grain chemistry in molecular clouds and…
We report the first detection of C$^{15}$N in diffuse molecular gas from a detailed examination of CN absorption lines in archival VLT/UVES spectra of stars probing local diffuse clouds. Absorption from the C$^{15}$N isotopologue is…
In 1992 the Far-Ultraviolet Space Telescope (FAUST) provided measurements of the ultraviolet (140-180nm) diffuse sky background at high, medium, and low Galactic latitudes. A significant fraction of the detected radiation was found to be of…
Context: Over the past thirty years a wealth of observations of CO and other molecules in optical/uv absorption in diffuse clouds has accumulated for which no comparable CO emission line data exist. Aims: To acquire mm-wave J=1-0 CO…
Due to the recent dramatic technological advances, infrared interferometry can now be applied to new classes of objects, resulting in exciting new science prospects, for instance, in the area of high-mass star formation. Although…
Laboratory results of the optical properties of vapor-deposited water ice, specifically the refractive index and extinction coefficient, are available mainly for a selective set of wavelengths and a limited number of deposition…
We present a high resolution (R~500) X-ray spectrum of the bright quasar H1821+643 (z=0.297), obtained in a 470 ksec Chandra observation. We search for X-ray absorption by highly ionized metal species, OVII and OVIII in particular, at the…
We use FUSE and STIS spectra to study intergalactic absorption towards the quasar PG1259+593 (z=0.478). We identify 135 intergalactic absorption lines with equivalent widths >10mA, tracing 78 absorption components in 72 Ly alpha/beta…
We have carried out a sensitive high-latitude (|b| > 15deg.) HI 21cm-line absorption survey towards 102 sources using the GMRT. With a 3-sigma detection limit in optical depth of ~0.01, this is the most sensitive HI absorption survey. We…
The distribution of a low-density transition temperature (10^4.5 - 10^5.5 K) gas in the interstellar medium conveys the character and evolution of diffuse matter in the Galaxy. This difficult to observe component of the ISM emits mainly in…
The main goal of this work is to compare the effects induced in ices of astrophysical relevance by high-energy ions, simulating cosmic rays, and by vacuum ultraviolet (UV) photons. This comparison relies on in situ infrared spectroscopy of…
We report on high resolution spectra of the bright QSO HS0747+4259 (zem = 1.90, V = 15.8) observed to search for intermediate redshift OVI absorption systems. The spectra were obtained by means of the Space Telescope Imaging Spectrograph…
Spectroscopic studies of ices in nearby star-forming regions indicate that ice mantles form on dust grains in two distinct steps, starting with polar ice formation (H2O rich) and switching to apolar ice (CO rich). We test how well the…