Free Access

Table 3

Ion column densities.

Ion log N(cm-2) a

Ne ix 15.96 16.59 15.37
O viib 16.24 15.93 15.86 16.07
O viii 16.03 15.71 15.92 15.70
O v 15.17 15.28 14.40
O iv 15.61 15.68 15.38
O iv (CIE) 15.56 15.51
O i 16.54 16.19
N vi 15.05 14.84 15.23 14.87
N i 15.81 15.56
C vi 15.34 15.41 14.97 15.22



The values are obtained by fitting the data with the slab model, i.e. without an assumption about the ionisation balance, except for O iv, for which we also show the value obtained under CIE assumption. The uncertainties include the systematic uncertainty of 1 mÅ and the allowance of vtot = 20–35 km s-1.


The value for RGS1, RGS2, and HRC is the weighted mean of the Lyα and Lyβ measurements. RGS2 only covers the Lyβ line.

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.