The Deuterium, Oxygen, and Nitrogen Abundance Toward LSE 44

We report on the abundance of interstellar neutral oxygen (OI) for 26 sightlines, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE), the International Spectroscopic Explorer (IUE), and the Hubble Space Telescope (HST). OI column densities are derived by measuring the equivalent widths of several ultraviolet absorption lines, and subsequently fitting those to a curve of growth. We consider both our general sample of 26 sightlines and a more restrictive sample o...

We report the detection of interstellar hydrogen deuteride (HD) toward the supernova remnant IC443, and the tentative detection of HD toward the Herbig Haro objects HH54 and HH7 and the star forming region GGD37 (Cepheus A West). Our detections are based upon spectral line mapping observations of the R(3) and R(4) rotational lines of HD, at rest wavelengths of 28.502 and 23.034 micron respectively, obtained using the Infrared Spectrograph onboard the Spitzer Space Telescope. ...

To measure interstellar atomic deuterium abundances, we used the Interstellar Medium Absorption Profile Spectrograph (IMAPS) to obtain spectra of gamma2 Vel and zeta Pup over the wavelength interval 930-1150 A at a resolving power of 80,000. The interstellar D I features are resolved and cleanly separated from interstellar H I in the Ly-delta and Ly-epsilon profiles of both sight lines, and also in the Ly-gamma profile of zeta Pup. The D I profiles were modeled using a veloci...

We present a new analysis of an absorption system in the spectrum of Q0014+813, with particular attention to a single cold cloud at redshift $z=2.797957$. Features are identified at this redshift corresponding to SiIII, SiIV, CIV, DI, and HI, all consistent with purely thermal broadening at $T\approx 19,000$K. The deuterium identification is confirmed by its narrow width and precise agreement with the silicon and carbon redshifts. The HI column is well constrained by a slight...

We present new measurements of the interstellar gas-phase oxygen abundance along the sight lines towards 19 early-type galactic stars at an average distance of 2.6 kpc. We derive O {\small I} column densities from {\it HST}/STIS observations of the weak 1355 \AA intersystem transition. We derive total hydrogen column densities [N(H {\small I})+2N(H$_2$)] using {\it HST}/STIS observations of \lya and {\it FUSE} observations of molecular hydrogen. The molecular hydrogen content...

Moderate and high-resolution measurements (R ~ 40,000) of interstellar resonance lines of D I, C II, N I, O I, Al II, and Si II (light ions) are presented for all available observed targets located within 100 pc which also have high-resolution observations of interstellar Fe II or Mg II (heavy ions) lines. All spectra were obtained with the Goddard High Resolution Spectrograph or the Space Telescope Imaging Spectrograph instruments aboard the Hubble Space Telescope. Currently...

We present results from 12 km/s resolution echelle spectroscopy of the bright $z=4.694$ QSO BR1202-0725. A preliminary analysis shows that high metallicity narrow line absorption clouds are present up to the redshift of the quasar. A damped Ly$\alpha$ system with an HI column density of $3.1 \times 10^{20}$ cm$^{-2}$ at $z=4.383$ has an [O/H] ratio that is about 0.01 solar, while another absorption system with an HI column density of $5.0 \times 10^{16}$ cm$^{-2}$ at $z=4.672...

The origin of the observed variability of the gas-phase D/H ratio in the local interstellar medium is still debated, and in particular the role of deuterium depletion onto dust grains. Here we extend the study of the relationship between deuterium and titanium, a refractory species and tracer of elemental depletion, and explore other relationships. We have acquired high resolution spectra for nine early-type stars using the VLT/UVES spectrograph, and detected the absorption l...

We present a theoretical study of the deuterated species detectability in various types of extragalactic star-forming regions based on our predictions of chemical abundances. This work is motivated by the past and current attempts at observing deuterated species in external galaxies such as NGC~253, IC~342 and the LMC. Here, we investigate the influence of the density, the temperature, the FUV radiation field, the cosmic ray ionisation, and the metallicity on the fractional a...

From the analysis of the near-UV spectrum of the QSO 2206-199, obtained with a long series of exposures with STIS on the HST, we deduce a value (D/H) = (1.65 +/- 0.35) x 10(-5) (1 sigma error) for the abundance of deuterium in the z(abs) = 2.0762 damped Lyman alpha system (DLA) along this sight-line. The velocity structure of this absorber is very simple and its neutral hydrogen column density, N(H I), is accurately known; the error in D/H is mostly due to the limited signal-...