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Astron. Astrophys. 331, 34-40 (1998)


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Modelling the Extended Narrow Line Region in NGC 1068

L.S. Nazarova 1, 3, P.T. O'Brien 1, M.J. Ward 1 and P.M. Gondhalekar 2

1 Department of Physics & Astronomy, University of Leicester, University Road, Leicester, LE1 7RH, UK
2 Rutherford Appleton Laboratory, Chilton, OXON, OX11 0QX, UK
3 Astronomical Society, Sternberg Astronomical Institute, Universitetskij prosp.13, Moscow, 119899, Russia

Received 7 July 1997 / Accepted 24 October 1997

Abstract

We present photoionization models of the high excitation gas in the Extended Narrow Line Region (ENLR) of NGC 1068. The ENLR line fluxes have been calculated allowing for attenuation of the central-source ionizing continuum as a function of distance from the centre. Diffuse continuum emission from low density ENLR gas is included as an important secondary source of ionization. The observed high excitation emission further than 25 arcsec from the centre of NGC 1068 can be fitted by photoionization models using a central-source luminosity of [FORMULA] erg s-1 between 1014.6 and 1018.4 Hz, with the continuum shape attenuated by nuclear gas with an integrated column density of N [FORMULA] cm-2. The reflected soft X-ray continuum from the attenuating gas could be responsible for about 10% of the observed, resolved circumnuclear soft X-ray continuum extending out to 15 arcsec from the centre (Wilson et al 1992).

Key words: galaxies: active – galaxies: nuclei – galaxies: individual (NGC 1068) – galaxies: Seyfert

Send offprint requests to: P.T. O'Brien

© European Southern Observatory (ESO) 1998

Online publication: February 4, 1998
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