Ongoing star formation in the BL lacertae object PKS 2005-489

Abstract

We present VLT long-slit optical spectroscopy of the luminous BL Lacertae object PKS 2005-489. The high signal-to-noise ratio and the good spatial resolution of the data allow us to detect the signatures of ongoing star formation in an extended rotating ring, at similar to 4 kpc from the nucleus. We find that the ring is almost perpendicular to the radio axis, and its total star formation rate is similar or equal to 1 M-circle dot yr(-1). We briefly discuss the concomitant presence of recent star formation and nuclear activity