We present new spectroscopic observations of the southern radio galaxyPKS1549-79 (z =0.152).Despite the flat spectrum character of the radio emissionfrom this source, our optical spectra show no sign of the broad permitted linesand non-stellar continuum characteristic of quasar nuclei and broad line radiogalaxies. However, the high ionization forbidden lines, including[OIII]5007,4959, are unusually broad for a narrow line radio galaxy (FWHM 1350km/s), and are blueshifted by 600 km/s relative to the low ionization linessuch as[OII]3726,3729. The [OII] lines are also considerably narrower (FWHM 650km/s) than the [OIII] lines, and have a redshift consistent with that of therecently-detected HI 21cm absorption line system. Whereas the kinematics of the[OIII] emission lines are consistent with outflow in an inner narrow lineregion, the properties of the [OII] emission lines suggest that they areemitted by a more extended and quiescent gaseous component. We argue that,given the radio properties of the source, our line of sight is likely to belying close to the direction of bulk outflow of the radio jets. In this case itis probable that the quasar nucleus is entirely obscured at optical wavelengthsby the material responsible for the HI absorption line system.The unusuallybroad [OIII] emission lines suggest that the radio source is intrinsicallycompact. Overall, our data are consistent the idea that PKS1549-79 is a radiosource in an early stage of evolution.
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