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Ultraviolet Properties of Multi-phase Gas Toward the Inner Galaxy
Frances H. Cashman, Andrew J. Fox, Debopam Som +6
We present a systematic study of the multi-phase interstellar gas in the Inner Galaxy using HST/STIS absorption spectroscopy of 16 massive stars located at spectroscopic distances…
Metals and a Search for Molecules in the Distant Universe: Magellan MIKE Observations of sub-DLAs at 2<z<3
Suraj Poudel, Varsha P. Kulkarni, Debopam Som +1
We present abundance measurements of the elements Zn, S, O, C, Si and Fe for four sub-DLAs at redshifts ranging from z=2.173 to z=2.635 using observations from the MIKE spectrograp…
Probing Structure in Cold Gas at with Gravitationally Lensed Quasar Sight Lines
Varsha P. Kulkarni, Frances H. Cashman, Sebastian Lopez +3
Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables study of spatial variations in the interstellar and/or circumgalactic medium of foreground galaxies. We rep…
Spectroscopic QUasar Extractor and redshift (z) EstimatorSQUEzE I: Methodology
Ignasi Pérez-Ràfols, Matthew M. Pieri, Michael Blomqvist +2
We present SQUEzE, a software package to classify quasar spectra and estimate their redshifts. SQUEzE is a random forest classifier operating on the parameters of candidate emissio…
A High Signal-to-Noise HST Spectrum Toward J1009+0713: Precise Absorption Measurements in the CGM of Two Galaxies
Cassandra Lochhaas, Smita Mathur, Stephan Frank +6
High signal-to-noise spectra toward background quasars are crucial for uncovering weak absorption in the circumgalactic medium (CGM) of intervening galaxies, such as the diagnostic…
Early metal enrichment of gas-rich galaxies at z~5
Suraj Poudel, Varsha P. Kulkarni, Sean Morrison +4
We present abundance measurements of elements O, C, Si and Fe for three gas-rich galaxies at z~5 using observations from the Very Large Telescope (VLT) and the Keck telescope in or…
Probing the Interstellar Dust in Galaxies over > 10 Gyr of Cosmic History
Varsha P. Kulkarni, Monique C. Aller, Donald G. York +3
This article is based on an invited talk given by V. P. Kulkarni at the 8th Cosmic Dust meeting. Dust has a profound effect on the physics and chemistry of the interstellar gas in…
Element Abundances in a Gas-rich Galaxy at z = 5: Clues to the Early Chemical Enrichment of Galaxies
Sean Morrison, Varsha P. Kulkarni, Debopam Som +3
Element abundances in high-redshift quasar absorbers offer excellent probes of the chemical enrichment of distant galaxies, and can constrain models for population III and early po…
Keck and VLT Observations of Super-damped Lyman-alpha Absorbers at z=2=2.5: Constraints on Chemical Compositions and Physical Conditions
Varsha P. Kulkarni, Debopam Som, Sean Morrison +3
We report Keck/ESI and VLT/UVES observations of three super-damped Lyman-alpha quasar absorbers with H I column densities log N(HI) >= 21.7 at redshifts z=2-2.5. All three absorber…
Atomic data for Zn II - Improving Spectral Diagnostics of Chemical Evolution in High-redshift Galaxies
Romas Kisielius, Varsha P. Kulkarni, Gary J. Ferland +3
Damped Lyman-alpha (DLA) and sub-DLA absorbers in quasar spectra provide the most sensitive tools for measuring element abundances of distant galaxies. Estimation of abundances fro…
Probing Interstellar Silicate Dust Grain Properties in Quasar Absorption Systems at Redshifts z<1.4
Monique C. Aller, Varsha P. Kulkarni, Donald G. York +3
Absorption lines in the spectra of distant quasars whose sightlines pass through foreground galaxies provide a valuable tool to probe the dust and gas compositions of the interstel…
Interstellar Silicate Dust in the z=0.89 Absorber Towards PKS 1830-211: Crystalline Silicates at High Redshift?
Monique C. Aller, Varsha P. Kulkarni, Donald G. York +3
We present evidence of a >10-sigma detection of the 10 micron silicate dust absorption feature in the spectrum of the gravitationally lensed quasar PKS 1830-211, produced by a fore…
Do Damped and Sub-damped Lyman-alpha Absorbers Arise in Galaxies of Different Masses?
Varsha P. Kulkarni, Pushpa Khare, Debopam Som +4
We consider the questions of whether the damped Lyman-alpha (DLA) and sub-DLA absorbers in quasar spectra differ intrinsically in metallicity, and whether they could arise in galax…