J/MNRAS/492/468 Chemical abundances of Seyfert 2 AGNs - I (Dors+, 2020)
Chemical abundances of Seyfert 2 AGNs - I.
Comparing oxygen abundances from distinct methods using SDSS.
Dors O.L., Freitas-Lemes P., Amores E.B., Perez-Montero E., Cardaci M.V.,
Hagele G.F., Armah M., Krabbe A.C., Faundez-Abans M.
<Mon. Not. R. Astron. Soc., 492, 468-479 (2020)>
=2020MNRAS.492..468D 2020MNRAS.492..468D (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Abundances, peculiar ; Galaxies, Seyfert ;
Redshifts ; Spectra, optical
Keywords: galaxies: abundances - galaxies: active - ISM: abundances -
galaxies: nuclei - galaxies: seyfert
Abstract:
We compare the oxygen abundance (O/H) of the narrow-line regions
(NLRs) of Seyfert 2 AGNs obtained through strong-line methods and from
direct measurements of the electron temperature (Te-method). The aim
of this study is to explore the effects of the use of distinct methods
on the range of metallicity and on the mass-metallicity relation of
active galactic nuclei (AGNs) at low redshifts (z~<0.4). We used the
Sloan Digital Sky Survey (SDSS) and NASA/IPAC Extragalactic Database
(NED) to selected optical (3000<λ(Å)<7000) emission line
intensities of 463 confirmed Seyfert 2 AGNs. The oxygen abundances of
the NLRs were estimated using the theoretical Storchi-Bergmann et al.
calibrations, the semi-empirical N2O2 calibration, the Bayesian
HII-CHI-MISTRY code and the Te-method. We found that the oxygen
abundance estimations via the strong-line methods differ from each
other up to ∼0.8dex, with the largest discrepancies in the
low-metallicity regime (12+log(O/H)~<8.5). We confirmed that the
Te-method underestimates the oxygen abundance in NLRs, producing
unreal subsolar values. We did not find any correlation between the
stellar mass of the host galaxies and the metallicity of their AGNs.
This result is independent of the method used to estimate Z.
Description:
In order to produce a sample of type-2 AGNs with observational
intensities of narrow optical emission lines, we used the measurements
of the Sloan Digital Sky Survey (SDSS; York et al.
2000AJ....120.1579Y 2000AJ....120.1579Y) DR7 data made available by MPA/JHU group. The
procedure of measuring the emission-line intensities is described in
details by Tremonti et al. (2004ApJ...613..898T 2004ApJ...613..898T). The data produced by
MPA/JHU are corrected for foreground (galactic) reddening using the
methodology presented by O'Donnell (1994ApJ...422..158O 1994ApJ...422..158O).
In order to classify objects as AGN like and as HII like, we used the
standard Baldwin-Phillips-Terlevich (BPT) diagrams (Baldwin, Phillips
& Terlevich 1981PASP...93....5B 1981PASP...93....5B; Veilleux & Osterbrock
1987ApJS...63..295V 1987ApJS...63..295V). And we used the criteria proposed by Kewley et
al. (2001ApJ...556..121K 2001ApJ...556..121K) and Perez-Montero et al.
(2013A&A...549A..25P 2013A&A...549A..25P).
Next, we compiled from the NED/IPAC (NASA/IPAC Extragalactic Database)
two catalogues containing basic information (classification) about
Seyfert 1 and Seyfert 2 galaxies. We use the SDSS objID provided by
both the NED/IPAC and the Garching data bases to match the data. In
this way, we found 112 Seyfert 1s and 463 Seyfert 2s.
For the resulting Seyfert 2 AGNs sample, reddening corrected
intensities (in relation to Hβ=1.0) of the
[OII]λ3726+3729, [NeIII]λ3869, [OIII]λ4363,
[OIII]λ5007, HeIλ5876, [OI]λ6300,
[NII]λ6584, [SII]λ6716, [SII]λ6731, and
[ArIII]λ7135 emission-lines, redshifts (z~<0.4), reddening
correction C(Hβ), the electron density are listed in the table.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 164 463 Emission-line intensities (relative to
Hβ=1) and properties of Seyfert 2 AGNs
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- ID [1/463] Internall object identifier
5- 23 A19 --- Name SDSS AGN name (JHHMMSS.ss+DDMMSS.s)
25- 31 F7.4 --- OII/Hb Line ratio
[OII]λ3726+3729/Hβ (1)
33- 38 F6.4 --- NeIII/Hb ?=0 [NeIII]λ3869/Hβ line
ratio (1)
40- 45 F6.4 --- OIII1/Hb ?=0 Line ratio [OIII]4363/Hβ (1)
47- 53 F7.4 --- OIII2/Hb Line ratio [OIII]5007/Hβ (1)
55- 60 F6.4 --- HeII/Hb ?=0 HeIIλ5876/Hβ line
ratio(1)
62- 67 F6.4 --- OI/Hb Line ratio [OI]λ6300/Hβ (1)
69- 74 F6.4 --- Ha/Hb Line ratio Hα/Hβ (1)
76- 81 F6.4 --- NII/Hb Line ratio [NII]λ6584/Hβ
(1)
83- 88 F6.4 --- SII1/Hb Line ratio [SII]λ6716/Hβ
(1)
90- 95 F6.4 --- SII2/Hb Line ratio [SII]λ6731/Hβ
(1)
97-103 F7.4 --- AIII/Hb ?=0 [AIII]λ7135/Hβ line
ratio (1)
105-109 F5.2 10+7Msun Mass AGN mass
111-117 F7.5 --- z Redshift
119-125 F7.5 --- e_z Error on z
127-133 F7.4 --- C(Hb) Reddening correction
135-139 I5 cm-3 ne Electron density (2)
141-144 F4.2 --- log(O/H)N2O2 12+log(O/H) obtained from N2O2
calibration proposed by
Castro et al. (2017MNRAS.467.1507C 2017MNRAS.467.1507C)
146-149 F4.2 --- log(O/H)Sb981 12+log(O/H) obtained from Sb98,1
calibration proposed by
Storchi-Bergmann (1998AJ....115..909S 1998AJ....115..909S)
151-154 F4.2 --- log(O/H)Sb982 12+log(O/H) obtained from Sb98,2
calibration proposed by
Storchi-Bergmann (1998AJ....115..909S 1998AJ....115..909S)
156-159 F4.2 --- log(O/H)Te 12+log(O/H) obtained from Te-method
161-164 F4.2 --- log(O/H)HII 12+log(O/H) obtained from the
HII-CHI-MINISTRY code (Perez-Montero
et al. 2019MNRAS.489.2652P 2019MNRAS.489.2652P)
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Note (1): Line ratio intensities are in relation to Hβ=1 and reddening
corrected. We take as zero the emission-line intensities that in the
SDSS data base have values lower than zero.
Note (2): Objects for which was not possible to derive the electron density
have been assigned the mean value of 650cm-3
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History:
From electronic version of the journal
(End) Ana Fiallos [CDS] 01-Mar-2023