Volume 371, Number 2, May IV 2001
|Page(s)||507 - 511|
|Section||Cosmology (including clusters of galaxies)|
|Published online||15 May 2001|
A two-phase model for the narrow line region of NGC 4151
Max-Planck-Institut für extraterrestrische Physik, Postfach 1312, 85741 Garching, Germany
Corresponding author: S. Komossa, firstname.lastname@example.org
Accepted: 16 March 2001
NGC 4151 is one of the brightest and best-studied Seyfert galaxies. Here, we present a two-phase model of the narrow-line region (NLR) of NGC 4151. This study is motivated by (i) the fact that the X-ray spectrum of NGC 4151 is among the flattest known for Seyferts, and (ii) the recent Chandra detection of an X-ray narrow-line region in this galaxy. X-ray spectra as flat as that of NGC 4151 ( ) are expected to favor the presence of two gas phases in pressure equilibrium (Krolik et al. 1981). In the present study, we show that a pronounced two-phase equilibrium develops in the extended emission-line region if we use the observed multi-wavelength spectrum of NGC 4151 to ionize the clouds. The material is stable to isobaric perturbations over a wide range of temperatures. We therefore propose that such a condition has arisen in the NLR of NGC 4151, and that it explains the detection of hot, extended X-ray gas which we identify as the NLR-cloud confining medium.
Key words: galaxies: Seyfert / galaxies: individual: NGC 4151 / galaxies: nuclei / galaxies: emission lines / X-rays: galaxies
© ESO, 2001
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.