Studies of the Interstellar Medium at Low and High Redshifts

Summary of Recent Activities:

• I was the principal investigator for the ISM SNAP Surveys, which were a series of Hubble Space Telescope (HST) observing programs to study the Galactic interstellar medium using absorption lines in spectra of O and B-type stars. With co-investigator David M. Meyer (Northwestern) and other collaborators, we have been studying a variety of interstellar cloud properties using the unique capabilities of the Space Telescope Imaging Spectrograph (STIS). Follow-up observations using STIS, the Far Ultraviolet Spectroscopic Explorer (FUSE) and ground based telescopes have also been obtained for a number of these stars.
• Working with David M. Meyer, Ulysses J. Sofia (Whitman College), and our former Northwestern graduate student Stefan Cartledge (LSU), I have been involved in projects to study the abundance of oxygen and carbon in translucent interstellar clouds using STIS. I have recently been working with a summer student to study the abundances and dust depletions of silicon and iron in these sightlines.
• Working with David M. Meyer and other collaborators, I have been studying structure in the interstellar medium on small (sub-parsec) scales. We have used a variety of both ground and space based instruments and telescopes.
• A group including myself, D. E. Welty (the PI), J.C. Blades (STScI), L.M. Hobbs, & D.G. York has used HST to study the lines-of-sight to stars in the Magellanic Clouds in detail. In addition, optical interstellar lines observed have been observed with the Anglo-Australian Telescope (at the AAO) and/or the ESO 3.6-meter toward stars in the Magellanic Clouds. For more information on these projects please check out Dan Welty's Magellanic Clouds research page.
• Working with Don York (UofChicago), Jim Truran (UofChicago), and Frank Timmes (LANL) , I have been studying the abundance of the element fluorine in the interstellar medium with FUSE. Since the nucleosynthetic sources of this element, and the degree to which they contribute to its abundance, are uncertain fluorine may be a particularly import tracer of both nucleosynthetic activity and (potentially) interstellar mixing.



• Absorption lines arising in intervening galaxies that are observed in spectra taken of QSOs provide one of the best ways to study the evolution of elemental abundances in the Universe. Recent efforts have been focused on studying low and moderate redshift QSO absorbers using HST, the MMT, and the ESO VLT.
  Recent papers include:
  Hubble Space Telescope Observations of Element Abundances in Low-Redshift Damped Ly-alpha Galaxies and Implications for the Global Metallicity-Redshift Relation Kulkarni, Fall, Lauroesch, York, Welty, Khare, & Truran 2005, ApJ, 618, 68
  The Most Metal-Rich Intervening Quasar Absorber Known Peroux, Kulkarni, Meiring, Ferlet, Khare, Lauroesch, Vladilo, & York 2006, Accepted for publication in A&A
  
• I am also a member of the Sloan Digital Sky Survey (SDSS) QSOALS Catalog project. Publications include:
  
  Average extinction curves and relative abundances for quasi-stellar object absorption-line systems at 1 <= z_abs < 2 York, Khare, Vanden Berk, Kulkarni, Crotts, Lauroesch, Richards, Schneider, Welty, Alsayyad, Kumar, Lundgren, Shanidze, Smith, Vanlandingham, Baugher, Hall, Jenkins, Menard, Rao, Tumlinson, Turnshek, Yip, & Brinkmann 2006, MNRAS, 367, 945

My publications can be accessed on-line using the ADS abstract service.

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