Anisotropic emission stellar population and x-ray sources in the seyfert 2 galaxy eso 138 - g01

Abstract

We present narrow-band CCD images of the high-excitation Seyfert 2 galaxy ES0138-G01, centred on the emission tines [O III] λ5007, Hα+[N II] λλ6548, 6584 and adjacent continua. The continuum-subtracted [O III] image presents an elongated jet-like structure to the west of the nucleus which is only weakly visible in the Hα image, and which we conclude is ionized by the nuclear source. The ionization map shows high excitation at the nucleus and at the 'jet'. The continuum ratio map shows that this galaxy is very blue for its morphological type, consistent with the large contribution of a young stellar population up to 3 kpc from the nucleus. We also propose that ESO138 - GO1 is the hard X-ray source previously identified with the nearby galaxy NGC 6621.