Searching for the hidden broad-line region in Centaurus A

Abstract

We present the first near-infrared (K-band) spectropolarimetric observations of the nuclear region of Centaurus A. Although the data are of high signal-to-noise ratio, polarized broad Brγ is not detected and we place a 3σ upper limit of 3.9 × 10-15 erg s-1 cm-2 in polarized flux. We find a correlation between the K-band nuclear continuum and broad Hα line luminosity and estimate the strength of broad Brγ based on a number of possible models.