2001/01/31 by N. Lehner, Nicolas Lehner, Kenneth R. Sembach +4
Physics and Astronomy · #Astro and Planetary Science #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Full width at half maximum #Galactic halo #Galaxy #Halo #Interstellar cloud #Interstellar medium #Ion #Ionization #Large Magellanic Cloud #Metallicity #Optics #Physics #Spectral line #Stellar, planetary, and galactic studies #Substructure #astro-ph
paper · pdf · doi:10.1086/320221
Accepted for publication in ApJ (April 10, 2001). Minor corrections in Figures 1 and 3, and in references
arxiv created 2001/03/20 · openalex publication_date 2001/04/20 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We present ultraviolet and optical spectra of DI 1388, a young star in the Magellanic Bridge, a region of gas between the Small and Large Magellanic Clouds. The data have signal-to-noise ratios of 20-45 and a spectral resolution of 6.5 km s -1 . Interstellar absorption by the Magellanic Bridge at v LSR ≈ 200 km s -1 is visible in the lines of C I, C II, C II*, C IV, N I, O I, Al II, Si II, Si III, Si IV, S II, Ca II, Fe II, and Ni II. The relative gas-phase abundances of C II, N I, O I, Al II, Si II, Fe II, and Ni II with respect to S II are similar to those found in Galactic halo clouds, despite a significantly lower metallicity in the Magellanic Bridge. The higher ionization species in the cloud have a column density ratio N (C +3 )/ N (Si +3 ) ~ 1.9, similar to that inferred for collisionally ionized Galactic cloud interfaces at temperatures ~10 5 K. We identify substructure in the stronger interstellar lines, with a broad component (FWHM ~ 20 km s -1 ) at ~179 km s -1 and a sharp component (FWHM ~ 11 km s -1 ) at 198 km s -1 . The abundance analysis for these clouds indicates that the feature at 198 km s -1 consists of a low electron density, mainly neutral gas that may be associated with an interface responsible for the highly ionized gas. The 179 km s -1 cloud consists of warmer, lower density gas that is partially ionized.