Optical spectroscopy of local type-1 AGN LINERs

DOI: 
10.1093/mnras/sty1811
Publication date: 
01/07/2018
Main author: 
Cazzoli, S.
IAA authors: 
Cazzoli, S.;Márquez, I.;Masegosa, J.;del Olmo, A.;Pović, M.
Authors: 
Cazzoli, S.;Márquez, I.;Masegosa, J.;del Olmo, A.;Pović, M.;González-Martín, O.;Balmaverde, B.;Hernández-García, L.;García-Burillo, S.
Journal: 
Monthly Notices of the Royal Astronomical Society
Refereed: 
Yes
Publication type: 
Article
Pages: 
1106-1162
Abstract: 
The Balmer emission originated in the broad line region (BLR) of active galactic nuclei (AGNs) could be either weak and difficult to detect, or even absent, for low luminosity AGNs, as LINERs. Our goals in this paper are threefold. First, we want to explore the AGN-nature of nearby type-1 LINERs. Second, we aim at deriving a reliable interpretation for the different components of emission lines by studying their kinematics and ionization mechanism. Third, we intend to probe the neutral gas in the nuclei of these LINERs. We study the 22 local (z < 0.025) type-1 LINERs from the Palomar Survey, on the basis of optical ground- and space-based long-slit spectroscopic observations taken with TWIN/CAHA and ALFOSC/NOT. Kinematics and fluxes of a set of emission lines, from Hβλ4861 to [S II]λλ6716,6731, and the NaDλλ5890,5896 doublet in absorption have been modelled and measured, after the subtraction of the underlying starlight. We also use ancillary spectroscopic data from HST/STIS. We found that the broad Hα component is sometimes elusive in our ground-based spectroscopy whereas it is ubiquitous for space-based data. By combining optical diagnostic diagrams, theoretical models (for AGNs, pAGB-stars and shocks) and the weak/strong-[O I] classification, we exclude the pAGBs-stars scenario in favor of the AGN as the dominant mechanism of ionisation in these LINERs, being shocks however relevant. The kinematical properties of the emission lines may indicate the presence of ionized outflows, preferentially seen in [O I]. However, the neutral gas outflows, diagnosed by NaD, would appear to be less frequent.
Database: 
ADS
SCOPUS
URL: 
https://ui.adsabs.harvard.edu/#abs/2018MNRAS.480.1106C/abstract
ADS Bibcode: 
2018MNRAS.480.1106C
Keywords: 
galaxies: active;galaxies: ISM;galaxies: kinematics and dynamics;techniques: spectroscopic;Astrophysics - Astrophysics of Galaxies