We show that a cooled region of shocked supernova ejecta forms in a type II
supernova-QSO wind interaction, and has a density, an ionization parameter, and
a column density compatible with those inferred for the high ionization
component of the broad emission line regions in QSOs. The calculations are
based on the assumption that the ejecta flow is described initially by a
similarity solution investigated by Chevalier (1982) and Nadyozhin (1985) and
is spherically symmetric. Heating and cooling appropriate for gas irradiated by
a nearby powerful continuum source is included in our model, together with
reasonable assumptions for the properties of the QSO wind. The model results
are also in agreement with observational correlations and imply reasonable
supernova rates.Comment: 13 pages, 7 figures, to be published in A&