Planetary nebula system of NGC 5128

By comparing CCD images centered on the characteristic emission line [O III] {lambda}5007{AA} and on the adjacent continuum, we identify a total of 785 PNs in areas extending 20kpc along the photometric major axis and covering the whole galaxy to 10kpc.

From these data, we form a complete sample of 224 PN's extending to a dereddened limiting magnitude of m_5007_=24.8, which extends 1.5mag down the PN luminosity function (PNLF). Adopting a foreground extinction of E(B-V)=0.1, we derive a distance to the galaxy of 3.5+/-0.2Mpc, in excellent agreement with the surface brightness fluctuation method. No population effect on the bright cutoff of PNLF is observed in the isophotal radius range of 2-16kpc, but the luminosity specific PN density ({alpha}_2.5_) seems to increase with radius inside of 7kpc, in agreement with the {alpha}_2.5_-color relation observed for other galaxies.