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Interstellar Krypton Abundances: The Detection of Kiloparsec-scale Differences in Galactic Nucleosynthetic History
Stefan I. B. Cartledge, J. T. Lauroesch, David M. Meyer +2
We present an analysis of Kr I 1236 line measurements from 50 sight lines in the Hubble Space Telescope Space Telescope Imaging Spectrograph and Goddard High Resolution Spectrograp…
Metal abundances at z<1.5: new measurements in sub-Damped Lyman-alpha Absorbers
C. Peroux, J. D. Meiring, V. P. Kulkarni +4
Damped Lyman-alpha systems (DLAs) and sub-DLAs seen toward background quasars provide the most detailed probes of elemental abundances. Somewhat paradoxically these measurements ar…
Average Properties of a Large Sample of z_abs ~ z_em associated Mg II Absorption Line Systems
D. Vanden Berk, P. Khare, D. G. York +16
We have studied a sample of 415 associated (z_ab z_em; relative velocity with respect to QSO <3000km/s) Mg II absorption systems with 1.0<=z_ab<=1.86, in the spectra of SDSS DR3 QS…
The chemical compositions of 10 new sub-DLAs and strong Lyman-limit systems at z < 1.5
Joseph D. Meiring, Varsha P. Kulkarni, James T. Lauroesch +4
We present chemical abundance measurements from medium resolution observations of 8 sub-damped Lyman-alpha absorber and 2 strong Lyman-limit systems at z < 1.5 observed with the MI…
New abundance determinations in z < 1.5 QSO absorbers: seven sub-DLAs and one DLA
Joseph D. Meiring, James T. Lauroesch, Varsha P. Kulkarni +4
We present chemical abundance measurements from high resolution observations of 7 sub-damped Lyman-alpha absorbers and 1 damped Lyman-alpha system at z<1.5. Three of these objects…
A Cold Nearby Cloud Inside the Local Bubble
David M. Meyer, J. T. Lauroesch, Carl Heiles +2
The high-latitude Galactic H I cloud toward the extragalactic radio source 3C 225 is characterized by very narrow 21 cm emission and absorption indicative of a very low H I spin te…
The nature of damped Lyman alpha and sub-damped Lyman alpha absorbers
Pushpa Khare, Varsha P. Kulkarni, Celine Peroux +3
We present arguments based on the measured abundances in individual damped Lyman alpha systems (DLAs) and sub-damped Lyman alpha systems (sub-DLAs), and also the average abundances…
The Role of Sub-damped Lyman-alpha Absorbers in the Cosmic Evolution of Metals
V. P. Kulkarni, P. Khare, C. Peroux +3
Observations of low mean metallicity of damped Lyman-alpha (DLA) quasar absorbers at all redshifts studied appear to contradict the predictions for the global mean interstellar met…
Metal-rich Damped/sub-Damped Lyman-alpha Quasar Absorbers at z<1
C. Peroux, J. D. Meiring, V. P. Kulkarni +5
Damped Lyman-alpha absorbers (DLAs), seen in absorption against a background quasar, provide the most detailed probes available of element abundances in the Universe over > 90 % of…
The Interstellar N/O Abundance Ratio: Evidence for Local Infall?
David C. Knauth, James T. Lauroesch, David M. Meyer
Sensitive measurements of the interstellar gas-phase oxygen abundance have revealed a slight oxygen deficiency ( 15%) toward stars within 500 pc of the Sun as compared to mor…
Elemental Abundance Measurements in Low-redshift Damped Lyman Alpha Absorbers
Joseph D. Meiring, Varsha P. Kulkarni, Pushpa Khare +6
We present elemental abundance measurements for 9 damped Ly-alpha systems (DLAs) and 1 sub-DLA at 0.1 < z < 1.5 from recent observations with the Multiple Mirror Telescope. Most of…
Average Extinction Curves and Relative Abundances for QSO Absorption Line Systems at 1 <= z_abs < 2
Donald G. York, Pushpa Khare, Daniel Vanden Berk +21
We have studied a sample of 809 Mg II absorption systems with 1.0 < z_abs < 1.86 in the spectra of SDSS QSOs, with the aim of understanding the nature and abundance of the dust and…
The Most Metal-Rich Intervening Quasar Absorber Known
C. Peroux, V. P. Kulkarni, J. Meiring +5
The metallicity in portions of high-redshift galaxies has been successfully measured thanks to the gas observed in absorption in the spectra of quasars, in the Damped Lyman-alpha s…
The Homogeneity of Interstellar Elemental Abundances in the Galactic Disk
Stefan I. B. Cartledge, J. T. Lauroesch, David M. Meyer +1
We present interstellar elemental abundance measurements derived from Space Telescope Imaging Spectrograph echelle observations of 47 sight lines extending up to 6.5 kpc through th…
The Evolution of Damped Lyman-alpha Absorbers: Metallicities and Star Formation Rates
Varsha P. Kulkarni, Donald G. York, James T. Lauroesch +8
The damped Lyman-alpha (DLA) and sub-DLA quasar absorption lines provide powerful probes of the evolution of metals, gas, and stars in galaxies. One major obstacle in trying to und…
Evidence for the presence of dust in intervening QSO absorbers from the Sloan Digital Sky Survey
P. Khare, D. G. York, D. Vanden Berk +17
We find evidence for dust in the intervening QSO absorbers from the spectra of QSOs in the Sloan Digital Sky Survey Data Release 1. No evidence is found for the 2175 A feature whic…
Hubble Space Telescope Observations of Element Abundances in Low-redshift Damped Lyman-alpha Galaxies and Implications for the Global Metallicity-Redshift Relation
Varsha P. Kulkarni, S. Michael Fall, James T. Lauroesch +4
Most models of cosmic chemical evolution predict that the mass-weighted mean interstellar metallicity of galaxies should rise with time from a low value solar at $z \si…
The Complex Interstellar Na I Absorption toward h and Chi Persei
Sean D. Points, James T. Lauroesch, David M. Meyer
Recent high spatial and spectral resolution investigations of the diffuse interstellar medium (ISM) have found significant evidence for small-scale variations in the interstellar g…
Metals and Dust in Intermediate-redshift Damped Ly-alpha Galaxies
Pushpa Khare, Varsha P. Kulkarni, James T. Lauroesch +3
We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several abso…
The Homogeneity of Interstellar Oxygen in the Galactic Disk
Stefan I. B. Cartledge, J. T. Lauroesch, David M. Meyer +1
We present an analysis of high resolution HST Space Telescope Imaging Spectrograph (STIS) observations of O I 1356 and H I Lyman-alpha absorption in 36 sight lines that probe a var…
Interstellar Carbon in Translucent Sightlines
U. J. Sofia, J. T. Lauroesch, D. M. Meyer +1
We report interstellar C II column densities or upper limits determined from weak absorption of the 2325.4029 A intersystem transition observed in six translucent sightlines with S…
The Homogeneity of Interstellar Krypton in the Galactic Disk
Stefan I. B. Cartledge, David M. Meyer, J. T. Lauroesch
We present an analysis of high resolution HST Space Telescope Imaging Spectrograph (STIS) observations of Kr I 1236 Angstrom absorption in seven sight lines that probe a variety of…
Variable NaI Absorption toward rho Leo : Biased Neutral Formation in the Diffuse Interstellar Medium?
J. T. Lauroesch, David M. Meyer
We present multi-epoch KPNO Coude Feed observations of interstellar NaI and CaII absorption toward the bright star rho Leo. Comparisons of the NaI profiles observed over a period o…
On the Origin of the High-Ionization Intermediate-Velocity Gas Toward HD 14434
David C. Knauth, J. Christopher Howk, Kenneth R. Sembach +2
We present Far Ultraviolet Spectroscopic Explorer and Space Telescope Imaging Spectrograph observations of high-ionization interstellar absorption toward HD 14434 [(l, b) = (135.1,…