AAS 202nd Meeting, May 2003
Session 11 Galaxies, Cosmology and Higher Redshift Objects
Poster, Monday, May 26, 2003, 9:20am-6:30pm, West Exhibit Hall

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[11.13] Identification of the 1500 km/s Lyman-alpha Absorber in the 3C273 Sightline

B. A. Keeney, J. T. Stocke (CASA, Univ. of Colorado), R. J. Weymann (Carnegie Observatories), M. L. Giroux (East Tennessee State Univ.), K. M. McLin (CASA, Univ. of Colorado)

Lyman alpha forest observations of the 3C273 sightline revealed the presence of a moderate column density (log NHI = 15.85 cm-2) absorber at cz ~1500 km/s. After searching the surrounding area for the galaxy responsible for this absorption, a dwarf galaxy (MB = -14.5) with a post-starburst spectrum was discovered 70 kpc away from the sightline (cz = 1556 km/s). Despite its elliptical appearance, this galaxy is well-fit by an exponential disk surface brightness profile, suggesting that it is actually a spiral galaxy which has been stripped of its gas. The Lyman-alpha absorber also has associated metal line absorption, and analysis of the age of the stellar population in the post-starburst galaxy suggests that metals from this galaxy could be transported to distances of 70 kpc in the amount of time since the starburst ended. This example suggests both that some moderate column density, metal-bearing Lyman-alpha absorbers are associated with dwarf galaxies and that outflowing winds from dwarf galaxies may input both metals and energy into significant volumes of the intergalactic medium around them.

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Bulletin of the American Astronomical Society, 35 #3
© 2003. The American Astronomical Soceity.