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Paper: The Local Lyα Forest: HI in Nearby Intergalactic Space
Volume: 240, Gas and Galaxy Evolution: A Conference in Honor of the 20th Anniversary of the VLA
Page: 21
Authors: Stocke, J. T.; Shull, J. Michael; Penton, S. V.; Gibson, B. K.
Abstract: Detecting HI using redshifted Lyα absorption lines is ~106 times more sensitive than using the 21 cm emission line. We review recent discoveries of HI Lyα absorbers made with the Hubble Space Telescope (HST) which have allowed us a first glimpse at gas in local intergalactic space between us and the ``Great Wall.'' Despite its mere 2.4 m aperture, HST can detect absorbers with column densities as low as those found using Keck at high redshifts (NHI ≈ 1012.5 cm-2). New results discussed here include: the evolution of absorbers with redshift, the location of absorbers relative to galaxies (including the two-point correlation function for absorbers), the metallicity of absorbers far from galaxies, and the discovery of hot ~105-6 K (shock-heated?) absorbers. The unique ability of VLA HI observations in discovering the galaxies nearest to these absorbers is stressed.
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