The extended narrow line region of NGC 4151. I - Emission line ratios and their implications

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.
Referencia bibliográfica

Astronomy and Astrophysics (ISSN 0004-6361), vol. 236, no. 1, Sept. 1990, p. 53-62.

Fecha de publicación:
9
1990
Número de autores
56
Número de autores del IAC
5
Número de citas
121
Número de citas referidas
115
Descripción
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.