Zinc and Chromium Abundances in Milky Way Interstellar Gas

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Session 12 -- Interstellar medium
Display presentation, Monday, 9, 1995, 9:20am - 6:30pm

[12.02] Zinc and Chromium Abundances in Milky Way Interstellar Gas

Robert J. Macke, Kenneth R. Sembach, Charles C. Steidel (MIT)

We present column densities for Zn~II and Cr~II along multiple lines of sight throughout the Milky Way Galaxy. We examined high dispersion International Ultraviolet Explorer (IUE) satellite archival images of several hundred early-type stars for interstellar absorption lines in these two species. The Zn~II and Cr~II lines fall on a sensitive portion of the IUE SWP detector and can be detected down to levels of about 10 m{\AA} for many stars. For objects having multiple well-exposed images, we have combined the data to improve the S/N ratio of the composite spectra. In combination with HST archival spectra, we use the IUE data set to provide measures of the relative vertical and spatial distributions of Zn~II and Cr~II in the Galaxy. We compare the abundances derived for the Milky Way along different lines of sight with those determined from quasar absorption line spectra of galaxies at moderate and high redshifts.

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