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arXiv · 1002.3401

The Low-Redshift Lyman Alpha Forest toward 3C 273

G. M. Williger·R. F. Carswell·R. J. Weymann·E. B. Jenkins·K. R. Sembach·T. M. Tripp·R. Davé·L. Haberzettl·S. R. Heap
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Abstract

We present an analysis of the Ly-a forest toward 3C 273 from the Space Telescope Imaging Spectrograph at ~7 km/s resolution, along with re-processed data from the Far Ultraviolet Spectroscopic Explorer. The high UV flux of 3C 273 allows us to probe the weak, low z absorbers. The main sample consists of 21 HI absorbers that we could discriminate to a sensitivity of log NHI~ 12.5. The redshift density for absorbers with 13.1 = 12.5, it is consistent with numerical model predictions. The Doppler parameter distribution is consistent with other low z samples. We find no evidence for a break in the column density power-law distribution to log NHI=12.3. A broad Ly-a absorber (BLA) is within Delta v =< 50 km/s and 1.3 local frame Mpc of two ~0.5L* galaxies, with an OVI absorber ~700 km/s away, similarly close to three galaxies and indicating overdense environments. We detect clustering on the Delta v<1000 km/s scale at 3.4 sigma significance for log NHI >= 12.6, consistent with the level predicted from hydrodynamical simulations, and indication for a Ly-a forest void at 0.09<z<0.12. We find at least two components for the z=0.0053 Virgo absorber, but the total NHI column is not significantly changed.

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G. M. Williger, R. F. Carswell, R. J. Weymann, E. B. Jenkins, K. R. Sembach, T. M. Tripp, R. Davé, L. Haberzettl, S. R. Heap. 2010-02-17. The Low-Redshift Lyman Alpha Forest toward 3C 273. https://doi.org/10.1111/j.1365-2966.2010.16519.x

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