Metals in the Intergalactic Medium

Preprint
Publisher Website
Google Scholar
  • 29 July 2003
Abstract
We use high spectral resolution (R=45000) and high S/N ratio (40-80 per pixel) spectra of 19 high-redshift (2.1<z_em1. We do not detect CIV absorption statistically associated with gas of tau(HI)<1. In addition, our observations strongly suggest that the CIV/HI ratio decreases with decreasing tau(HI). We observe that for tau(HI)~1, log CIV/HI < -3.2 . This does not prevent a small fraction of this gas from being associated with strong metal lines as a probable consequence of the IGM enrichment being highly inhomogeneous. We detect the presence of OVI down to tau(HI)~0.2 with log OVI/HI~-2.0. We show that OVI absorption in the lowest density gas is located within ~400 km/s from strong HI lines. This suggests that this OVI phase may be part of winds flowing away from overdense regions. There is no OVI absorption, at tau(HI)<1, associated with gas located at velocities larger than ~400 km/s away from strong absorption lines. Therefore, at the limit of present surveys, the presence of metals in the underdense regions of the IGM is still to be demonstrated.

This publication has 0 references indexed in Scilit: