J/MNRAS/501/1370 Chemical abundances of Seyfert 2 AGNs IV (Dors+, 2021)
Chemical abundances of Seyfert 2 AGNs
IV. Composite models calculated by photoionization + shocks.
Dors O.L., Contini M., Riffel R.A., Perez-Montero E., Krabbe A.C.,
Cardaci M.V., Hagele G.F.
<Mon. Not. R. Astron. Soc., 501, 1370-1383 (2021)>
=2021MNRAS.501.1370D 2021MNRAS.501.1370D (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, Seyfert ; Active gal. nuclei ; Abundances, peculiar ;
Redshifts ; Optical
Keywords: galaxies: abundances - galaxies: active - galaxies: evolution -
galaxies: formation - galaxies: ISM - galaxies: nuclei
galaxies: Seyfert
Abstract:
We build detailed composite models of photoionization and shock
ionization based on the SUMA code to reproduce emission lines emitted
from the Narrow Line Regions (NLR) of Seyfert 2 nuclei. The aim of
this work is to investigate diagram active galactic nucleus (AGN)
positions according to shock parameters, shock effects on the gas
temperature and ionization structures and derive a semi-empirical
abundance calibration based on emission-line ratios little sensitive
to the shock presence. The models were used to reproduce optical
(3000<λ(Å)<7000) emission line intensities of 244 local
(z~<0.4) Seyfert 2s, whose observational data were selected from Sloan
Digital Sky Survey DR7. Our models suggest that shocks in Seyfert 2
nuclei have velocities in the range of 50-300km/s and imply a narrower
metallicity range (0.6~<(Z/Z☉)~<1.6) than those derived using
pure photoionization models. Our results indicate that shock velocity
in AGNs cannot be estimated using standard optical line ratio
diagrams, based on integrated spectra. Our models predict a different
temperature structure and O+/O and O2+/O fractional abundances
throughout the NLR clouds than those derived from pure photoionization
models, mainly in shock-dominated objects. This suggests that, in
order to minimize the shock effects, the combination of emission-lines
emitted by ions with similar intermediate ionization potential could
be good metallicity indicators. Finally, we derive two calibrations
between the N/O abundance ratio and the
N2O2=log([NII]λ6584/[OII]λ3727) and
N2=log([NII]λ6584/Hα) indexes which agree with that
derived from pure photoionization models.
Description:
We consider optical narrow emission line intensities
(3600<λ(Å)<7200) of a sample of Seyfert 2 galaxies compiled
by Dors et al. (2020MNRAS.492..468D 2020MNRAS.492..468D, Cat. J/MNRAS/492/468). These data
were taken from SDSS-DR7 (York et al. 2000AJ....120.1579Y 2000AJ....120.1579Y; Abazajian,
Adelman-McCarthy & Agueros M. A. et 2009ApJS..182..543A 2009ApJS..182..543A) and the
emission line intensity measurements are made available by the MPA/JHU
group. To select the objects, Dors et al. (2020MNRAS.492..468D 2020MNRAS.492..468D, Cat.
J/MNRAS/492/468) applied the criteria to separate AGN-like and SF-like
objects proposed by Kewley et al. (2001ApJ...556..121K 2001ApJ...556..121K,
2006MNRAS.372..961K 2006MNRAS.372..961K) and Perez-Montero et al. (2013A&A...549A..25P 2013A&A...549A..25P)
and based on BPT diagrams. After selecting a sample of AGNs, Dors et
al. (2020MNRAS.492..468D 2020MNRAS.492..468D, Cat. J/MNRAS/492/468) carried out a
cross-correlation between basic information from the SDSS-DR7 and in
NED/IPAC3 (NASA/IPAC Extragalactic Data base) catalogues in order to
obtain only Seyfert 2 AGNs. This procedure eliminates from the sample
SFs, star-forming galaxies, Seyfert 1 galaxies, quasars, and Planetary
Nebulae.
We built models by using the suma code (Viegas-Aldrovandi & Contini
1989ApJ...339..689V 1989ApJ...339..689V) in order to reproduce the observed spectra of
each object of our sample. This code has the advantage of considering
a combination of two ionization sources: the photoionization flux from
the AC and collisional effects from the shock. A detailed description
of the input parameters is given by Contini (2019MNRAS.488.4487C 2019MNRAS.488.4487C).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 130 488 De-reddened observed and predicted fluxes
(relative to Hβ=1.00) for our sample of
Seyfert 2 nuclei
table2.dat 51 244 Model parameters selected to fit the observation
emission-line ratios of each object of the
sample
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See also:
II/294 : The SDSS Photometric Catalog, Release 7
(Adelman-McCarthy+, 2009)
J/MNRAS/492/468 : Chemical abundances of Seyfert 2 AGNs - I (Dors+, 2020)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Source identifier (1)
6- 24 A19 --- Name SDSS source name
(JHHMMSS.ss+DDMMSS.s)
26- 32 F7.4 --- [OII]3726+3729/Hb De-reddened [OII]3726+3729 flux
relative to Hβ
34- 39 F6.4 --- [NeIII]3869/Hb De-reddened [NeIII]3869 flux
relative to Hβ
41- 46 F6.4 --- [OIII]4363/Hb De-reddened [OIII]4363 flux
relative to Hβ
48- 53 F6.3 --- [OIII]4959+5007/Hb De-reddened [OIII]4959+5007 flux
relative to Hβ
55- 60 F6.4 --- HeII5876/Hb De-reddened HeII5876 flux
relative to Hβ
62- 71 A10 --- [OI]6300/Hb De-reddened [OI]6300 flux
relative to Hβ
73- 78 F6.4 --- Ha/Hb De-reddened Hα flux
relative to Hβ
80- 85 F6.4 --- [NII]6584/Hb De-reddened [NII]6584 flux
relative to Hβ
87- 92 F6.4 --- [SII]6716/Hb De-reddened [SII]6716 flux
relative to Hβ
94- 99 F6.4 --- [SII]6731/Hb De-reddened [SII]6731 flux
relative to Hβ
101- 106 F6.4 --- [AIII]7135/Hb De-reddened [AIII]7135 flux
relative to Hβ
108- 114 F7.4 10+7Msun Mass ? Stellar mass
116- 122 F7.5 --- z ? Redshift
124- 130 F7.5 --- e_z ? Error on z
--------------------------------------------------------------------------------
Note (1): The observed values are listed in the lines with the identification
of each object. The predicted values are listed in the lines starting
with the label m.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- ID Model source identifier
6- 8 I3 km/s Vs Shock velocity
10- 12 I3 cm-3 n0 Atomic pre-shock density
14- 21 F8.3 10+16cm D Geometrical thickness of the cloud
23- 28 F6.4 10+10ph/cm2/s/eV F ? Radio flux emitted vy the AGN
30- 33 F4.2 10-4 N/H N/H abundance
35- 37 F3.1 10-4 O/H O/H abundance
39- 43 F5.3 10-4 S/H S/H abundance
45- 51 F7.5 mW/m2 F(Hbeta) Flux of Hβ calculated at the
nebula
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History:
From electronic version of the journal
References:
Dors et al., Paper I 2020MNRAS.492..468D 2020MNRAS.492..468D, Cat. J/MNRAS/492/468
Carvalho et al., Paper II 2020MNRAS.492.5675C 2020MNRAS.492.5675C
Dors et al., Paper III 2020MNRAS.496.3209D 2020MNRAS.496.3209D
Riffel et al., Paper V 2021MNRAS.501L..54R 2021MNRAS.501L..54R
(End) Ana Fiallos [CDS] 17-Oct-2023