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The Low-Redshift Lyman Alpha Forest toward PKS 0405-123

G. M. Williger·S. R. Heap·R. J. Weymann·R. Dave·E. Ellingson·R. F. Carswell·T. M. Tripp·E. B. Jenkins
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Abstract

We present STIS 7km/s resolution data of the Ly-a forest toward PKS0405-123 (z=0.574). We make two samples. The strong sample (60 systems) has column density logNHI>13.3 over 0.002 13.1 at 0.020 =47+-22km/s; for the weak, =44+-21km/s. Line blending and s/n effects likely inflate b. The redshift density dN/dz is consistent with previous, lower resolution results for logNHI>14.0. For 13.1 13.3, consistent with a numerical model. There is a void in the strong sample at 0.0320 13.5-14.0. The strength is similar to that of the galaxy-galaxy correlation for our sample, implying that such Ly-a systems have mass log M/Msun= 11.3+1.0-0.6. Including lower column density systems in the sample shows correlations only out to Delta v <125km/s, as would be expected for smaller density perturbations. Galaxy counts and local HI column density appear correlated, peaking at ~5000km/s. We also give column densities for Galactic species. (Abridged)

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G. M. Williger, S. R. Heap, R. J. Weymann, R. Dave, E. Ellingson, R. F. Carswell, T. M. Tripp, E. B. Jenkins. 2005-08-31. The Low-Redshift Lyman Alpha Forest toward PKS 0405-123. https://doi.org/10.1086/498127

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