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The Magellanic Bridge as a DLA System: Physical Properties of Cold Gas toward PKS0312-770 by Misawa, Toru; Charlton, Jane C.; Kobulnicky, Henry A.; Wakker, Bart P.; Bland-Hawthorn, Joss is a scholarly article available to read on EtoBox.

What is The Magellanic Bridge as a DLA System: Physical Properties of Cold Gas toward PKS0312-770 about?

We measure the physical properties of a local multi-component absorption-line system at V_sol ~ 200 km/s toward the quasar PKS0312-770 behind the Magellanic Bridge (MB) using Hubble Space Telescope STIS spectroscopy in conjunction with photoionization modeling. At an impact parameter of ~ 10 kpc from the Small Magellanic Cloud (SMC), this sightline provides a unique opportunity to probe the chemical properties and ionization structure in a nearby absorption line system with a column density of logN(HI) ~ 20.2, at the transition between Damped Lyman Alpha (DLA) and sub-DLA systems. We find that metallicity of -1.0 < logZ < -0.5 and ionization parameter of -6 < logU < -5 for three low-ionization components and logU ~ -2.6 for one high-ionization component. One component at V_sol = 207 km/s shows an alpha-element abundance log(Si/H) ~ -5.0, making it ~ 0.2 dex more metal rich than both SMC H II regions and stars within the MB and the SMC. The N/Si ratio in this component is log(N/Si) = -0.3+/-0.1, making it comparable to other N-poor dwarf galaxies and ~ 0.2 dex lower than H II regions in the SMC. Another component at V_sol = 236 km/s shows a similar Si/H ratio but has log(N/Si) = -1.

Author

Misawa, Toru; Charlton, Jane C.; Kobulnicky, Henry A.; Wakker, Bart P.; Bland-Hawthorn, Joss

Published

2009

Language

EN