We have discovered an error in Column 9 of Table 2 in the original paper. This column reports the fit flags, indicating which model a source prefers: a simple power-law (SPL; flag = 1), a fixed power-law plus intrinsic absorption (FPL; flag = 2), or an absorbed power-law (APL; flag = 3). The table of the original paper mistakenly reports all flag = 3 sources as having flag = 2, and all flag = 2 sources as having flag = 1, so that only 32 sources prefer an absorption model.

We have updated Table 2 to print out the correct fit flags for each source, resulting in 55 sources that prefer an absorption model. Since the fit flags determine which numbers are reported for the remaining columns of Table 2, these numbers are updated as well. The abstract and text of the original paper report the correct number of absorbed sources, so the conclusions are unaffected.

In addition, a minor rounding error was found in the SDSS names of some objects, and so we replace both Tables 1 and 2 with corrected versions.

Published 2009 November 3