Spectropolarimetry of the Circinus galaxy

High quality 4500–6800 Å spectropolarimetric observations of the Circinus galaxy are reported. These show polarized and relatively broad (FWHM∼3300 km/s) Hα (as well as marginal Hβ) arising from a <3′′ (<60 pc) region centered on the nucleus and coincident with the the peak of the narrow line region. Broad Hα might also be present ∼8′′ (160 pc) SE from the nucleus and close to the dust lane, but the result is only marginal and should be verified by higher s/n data. The continuum is dominated by stellar emission with ≤3% contribution from the scattered AGN continuum, and all the light (i.e. all the stellar continuum and narrow lines) is polarized, most probably by transmission through and scattering by dust in the disk. The data are compatiblewith a simplemodelwhere the scattered broad lines and AGN emission are quite polarized (P∼25%) but account for only 1% of the observed continuum. The scattered broad Hα has an equivalent width Wλ'400 Å, a flux similar to the narrow Hα and a luminosity '5 105 L . Assuming an efficiency of 1% for the BLR mirror, the intrinsic luminosity of the broad Hα is roughly 5 107 L and ∼0.5% of the FIR luminosity, a ratio similar to those found in type 1 Seyferts. Specific prediction for future observations are also presented.