The emission-line spectrum of KUG 1031+398 and the Intermediate Line Region

A.C. Gonçalves, P. Véron and M.-P. Véron-Cetty

Observatoire de Haute-Provence (CNRS), F-04870 Saint Michel l'Observatoire, France

Astronomy & Astrophysics, Received  /  Accepted

Abstract:

We present results based on the analysis of optical spectra of KUG 1031+398, a Narrow Line Seyfert 1 (NLS1) galaxy for which Mason et al. (1996) reported evidence for a line-emitting region ``intermediate'' (both in terms of velocity and density) between the conventional broad and narrow line regions (BLR and NLR, respectively). From our observations and modelling of the spectra, we get a consistent decomposition of the line profiles into four components: an extended Hii region with unresolved lines, two distinct Seyfert-type clouds identified with the NLR, and a relatively narrow ``broad line'' component emitting only Balmer lines but no forbidden lines. Therefore, and although we find this object to be exceptional in having line-emission from the BLR with almost the same width as the narrow lines, our interpretation of the data does not support the existence of an ``intermediate'' line region (ILR).

Key Words : galaxies: active - galaxies: Seyfert - galaxies: individual: KUG 1031+398