Main Image
Volume 328 - Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe (NLS1-2018) - Optical properties of NLS1 galaxies
Narrow Line Seyfert 1 galaxies in the context of Quasar Main Sequence
B. Czerny,* S. Panda, M. Śniegowska, S. Kozlowski, M. Nikolajuk, P. Du, B. You
*corresponding author
Full text: pdf
Pre-published on: 2018 June 18
Published on: 2018 December 21
Abstract
Narrow-line Seyfert 1 galaxies are defined on the basis of their line widths, and they are generally considered to be high Eddington ratio sources. But in the context of the Quasar Main Sequence, high Eddington rate sources are those which have weak [O III] lines and strong Fe II lines. There is an overlap between the two populations, but they are not identical. Thus these two selection criteria give a different view on which objects are actually high Eddington ratio sources. We discuss this issue in the context of the broad band spectral energy density, emission line shape modeling, Fe II pseudo-continuum strength, and the level of X-ray variability. We also discuss the issue of the viewing angle and the insight one can gain from spectropolarimetric observations. We conclude that there is no single driver behind the Quasar Main Sequence, and the Eddington ratio of the source cannot be determined from the source location on the optical plane alone. On the other hand, an expected range of AGN parameters combined with a simple model of the Fe II production represent well the observed coverage pattern of the plane, with not much effect needed from the dispersion due to the viewing angle.
DOI: https://doi.org/10.22323/1.328.0030
Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.