Bibcode
Penston, M. V.; Robinson, A.; Alloin, D.; Appenzeller, I.; Aretxaga, I.; Axon, D. J.; Baribaud, T.; Barthel, P.; Baum, S. A.; Boisson, C.; de Bruyn, A. G.; Clavel, J.; Colina, L.; Dennefeld, M.; Diaz, A.; Dietrich, M.; Durret, F.; Dyson, J. E.; Gondhalekar, P.; van Groningen, E.; Jablonka, P.; Jackson, N.; Kollatschny, W.; Laurikainen, E.; Lawrence, A.; Masegosa, J.; McHardy, I.; Meurs, E. J. A.; Miley, G.; Moles, M.; O'Brien, P.; O'Dea, C.; del Olmo, A.; Pedlar, A.; Perea, J.; Perez, E.; Perez-Fournon, I.; Perry, J.; Pilbratt, G.; Rees, M.; Robson, I.; Rodriguez-Pascual, P.; Rodriguez Espinosa, J. M.; Santos-Lleo, M.; Schilizzi, R.; Stasińska, G.; Stirpe, G. M.; Tadhunter, C.; Terlevich, E.; Terlevich, R.; Unger, S.; Vila-Vilaro, V.; Vilchez, J.; Wagner, S. J.; Ward, M. J.; Yates, G. J.
Bibliographical reference
Astronomy and Astrophysics (ISSN 0004-6361), vol. 236, no. 1, Sept. 1990, p. 53-62.
Advertised on:
9
1990
Citations
121
Refereed citations
115
Description
The paper presents the first results from long-slit spectra of the
Seyfert galaxy NGC 4151 which give average diagnostic ratios of weak
lines in the Extended Narrow Line Region (ENLR) of the galaxy and the
first direct density measurement in an ENLR. These data confirm that the
ENLR is kinematically undisturbed gas in the disk of the galaxy which is
illuminated by an ionizing continuum stronger by a factor of 13 than a
power law interpolated between recently observed ultraviolet and X-ray
fluxes. Explanations of this apparent excess include a hot thermal
continuum, time variations, and an anisotropic rotation field.