Dependence of the emission line intensitites of Seyfert galaxies on the colar index

Astrophysics ◽  
1978 ◽  
Vol 13 (3) ◽  
pp. 241-246
Author(s):  
M. A. Arakelyan
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies

scholarly journals The Excitation Mechanism of Emission‐Line Regions in Seyfert Galaxies

1999 ◽  
Vol 521 (2) ◽  
pp. 531-546 ◽  
Author(s):  
Ian Evans ◽  
Anuradha Koratkar ◽  
Mark Allen ◽  
Michael Dopita ◽  
Zlatan Tsvetanov
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies ◽  
Excitation Mechanism

scholarly journals Dust Distribution in IRAS Seyfert Galaxies

1994 ◽  
Vol 159 ◽  
pp. 355-355
Author(s):  
M. G. Pastoriza ◽  
Charles Bonatto ◽  
Eduardo Bica ◽  
T. Storchi-Bergmann
Keyword(s):  
Emission Line ◽  
Power Law ◽  
Dust Emission ◽  
Seyfert Galaxies ◽  
Emission Model ◽  
Line Region ◽  
Population Type ◽  
The Galaxy ◽  
Dilution Effects ◽  
Dust Distribution

Observational evidences of dust in the nuclear region of AGNs are substantial (Rudy 1984, ApJ, 284, 33; Jones et al. 1984, PASP, 96, 692). The ionization cones observed in several Seyfert galaxies has been interpreted as shadowing effects by a dust obscuring torus which hides the broad emission line region (BLR) and the central source (Wilson 1992; Storchi-Bergmann, Mulchaey and Wilson 1992, ApJ 395, L73). A large sample of optical and far-IR data for IRAS Seyfert galaxies has been analysed together with dust emission models (Bonatto and Pastoriza 1993), where it has been concluded that the same dust emission model can be applied to both Seyfert types. In order to further study the effects of dust in the spectra of active galactic nuclei, we have obtained spectrophotometry of 21 IRAS Seyfert galaxies in the range 3500–7200 Å and analyse them in conjuction with their IRAS fluxes. The stellar population type is derived from comparisons with normal galaxy templates using dilution effects in the K CaII line as discriminator. For 55% of the sample the population is of late type. For the rest, blue continua due to recent star formation and/or power-law may amount up to 30% at 4000Å. We conclude that the bulge stellar populations of IRAS Seyfert galaxies are similar to those of normal spirals, except that they are more reddened by E(B-V)i ∼ 0.20. Population-subtracted emission line ratios indicate on average stronger reddening for the narrow-line region (E(B-V)l ∼ 0.8. From photoionization models a power-law index for the ionizing continuum α=1.5, and a metallicity larger than solar are obtained. The most luminous IRAS galaxy of the sample (IRAS555) is discuss in detail: in order to be compatible with the observed IRAS fluxes and the optical stellar continuum, the ionizing continuum must be reddened by AV > 10 magnitudes. Consequently a dust structure in this galaxy appears to be increasingly affecting stars and gas towards the galaxy center.

scholarly journals On the Effects of Dissipative Turbulence on the Narrow Emission‐Line Ratios in Seyfert Galaxies

2007 ◽  
Vol 668 (2) ◽  
pp. 730-737 ◽  
Author(s):  
S. B. Kraemer ◽  
M. C. Bottorff ◽  
D. M. Crenshaw
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies ◽  
Dissipative Turbulence ◽  
Narrow Emission

An Emission-Line Imaging Survey of Early-Type Seyfert Galaxies. II. Implications for Unified Schemes

1996 ◽  
Vol 467 ◽  
pp. 197 ◽  
Author(s):  
John S. Mulchaey ◽  
Andrew S. Wilson ◽  
Zlatan Tsvetanov
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies ◽  
Early Type ◽  
Line Imaging

scholarly journals High-Ionization Nuclear Emission-Line Region of Seyfert Galaxies

2000 ◽  
Vol 119 (6) ◽  
pp. 2605-2628 ◽  
Author(s):  
Tohru Nagao ◽  
Yoshiaki Taniguchi ◽  
Takashi Murayama
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies ◽  
Line Region ◽  
High Ionization

Stability of Emission-Line Clouds in Seyfert Galaxies

1989 ◽  
pp. 303-304
Author(s):  
William G. Mathews ◽  
Sylvain Veilleux
Keyword(s):  
Emission Line ◽  
Seyfert Galaxies
Sign in / Sign up

Export Citation Format

Share Document