  The Unification Model for active galactic nuclei posits that Seyfert 2s are
intrinsically like Seyfert 1s, but that their broad-line regions (BLRs) are
hidden from our view. A Seyfert 2 nucleus that truly lacked a BLR, instead of
simply having it hidden, would be a so-called "true" Seyfert 2. No object has
as yet been conclusively proven to be one. We present a detailed analysis of
four of the best "true" Seyfert 2 candidates discovered to date: IC 3639, NGC
3982, NGC 5283, and NGC 5427. None of the four has a broad H-alpha emission
line, either in direct or polarized light. All four have rich, high-excitation
spectra, blue continua, and Hubble Space Telescope (HST) images showing them to
be unresolved sources with no host-galaxy obscuration. To check for possible
obscuration on scales smaller than that resolvable by HST, we obtained X-ray
observations using the Chandra X-ray Observatory. All four objects show
evidence of obscuration and therefore could have hidden BLRs. The picture that
emerges is of moderate to high, but not necessarily Compton-thick, obscuration
of the nucleus, with extra-nuclear soft emission extended on the
hundreds-of-parsecs scale that may originate in the narrow-line region. Since
the extended soft emission compensates, in part, for the nuclear soft emission
lost to absorption, both absorption and luminosity are likely to be severely
underestimated unless the X-ray spectrum is of sufficient quality to
distinguish the two components. This is of special concern where the source is
too faint to produce a large number of counts, or where the source is too far
away to resolve the extended soft X-ray emitting region.
