Complex absorption in the Seyfert 1 galaxy ESO 055620-3820.2

We report the results from an ASCA observation which yields the first contaminated hard X-ray spectrum of the Seyfert 1 galaxy EXO 055620-3820.2. We find the source spectrum to exhibit a complex structure below 2 keV, indicating that the continuum is attenuated either by an ionized absorber fully or partially covering the X-ray source, or a neutral absorber partially covering the source. While the X-ray data alone do not allow us to distinguish between these models, consideration of the optical properties of this highly reddened nucleus suggests that partial coveting by neutral material is unlikely, as it implies an unusually large intrinsic optical flux. We find a good fit to the X-ray data, and consistency with the observed optical properties of the source, with either 96% of the source covered by a column of 3.1 × 10²² cm^-2 of low-ionization gas or full covering by a column of 3.6 × 10²² cm^-2 of highly ionized gas. Both models required extinction of the optical continuum by dust in the host galaxy with Av ∼ 2 mag. We find evidence for a column of neutral material associated with this dust. The partial-coveting models leave a residual soft excess below 1 keV, and the possible origin of this soft emission is also discussed. We detect an iron K-shell emission line, which appears to be significantly broad, with an equivalent width (∼ 300 eV) exceeding that predicted from the absorbing material along the line of sight. The line is consistent with emission from neutral iron, and we find a FWHM for the line of 31,000-77,000 km s^-1, similar to several other Seyfert spectra reported recently.