J/MNRAS/431/836 Type 1 AGN at low z. III. (Stern+, 2013)
Type 1 AGN at low z. III. The optical narrow-line ratios.
Stern J., Laor A.
<Mon. Not. R. Astron. Soc., 431, 836-857 (2013)>
=2013MNRAS.431..836S 2013MNRAS.431..836S
ADC_Keywords: Active gal. nuclei ; Galaxies, Seyfert ; Spectroscopy
Keywords: galaxies: Seyfert
Abstract:
We present the optical narrow-line ratios in a Sloan Digital Sky
Survey (SDSS) based sample of 3175 broad Hα selected type 1
active galactic nuclei (AGN), and explore their positions in the BPT
diagrams as a function of the AGN and the host properties. We find the
following: (1) the luminosities of all measured narrow lines
(Hα, Hβ, [OIII], [NII], [SII], [OI]) show a Baldwin
relation relative to the broad Hα luminosity LbHα, with
slopes in the range of 0.53-0.72. (2) About 20 percent of the type 1
AGN reside within the "Composite" and "star-forming" (SF) regions of
the Baldwin, Phillips & Terlevich (BPT) diagrams. These objects also
show excess narrow Hα and ultraviolet (UV) luminosities, for
their LbHα, consistent with contribution from star formation
which dominates the narrow-lines emission, as expected from their
positions in the BPT diagrams. (3) The type 1 which reside within the
AGN region in the BPT diagrams, are offset to lower [SII]/Hα and
[NII]/Hα luminosity ratios, compared to type 2 AGN. This offset
is a selection effect, related to the lower AGN/host luminosity
selection of the type 2 AGN selected from the SDSS galaxy sample. (4)
The [NII]/Hα and [NII]/[SII] ratios in type 1 AGN increase with
the host mass, as expected if the mass-metallicity relation of
quiescent galaxies holds for the AGN narrow-line region (NLR). (5) The
broad lines optical Fe ii is higher for a higher [NII]/Hα, at a
fixed Lbol and Eddington ratio L/LEdd. This suggests that the broad
line region metallicity is also related to the host mass. (6) The
fraction of AGN which are low-ionization nuclear emission-line regions
(LINERs) increases sharply with decreasing L/LEdd. This fraction is
the same for type 1 and type 2 AGN. (7) The BPT position is unaffected
by the amount of dust extinction of the optical-UV continuum, which
suggests that the extincting dust resides on scales larger than the
narrow-line region (NLR).
Description:
The T1 sample of type-1 AGNs is selected from the SDSS-DR7 (II/294).
SDSS spectra with S/N>10 were used
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 49 3175 The AGN and host characteristics of the T1 sample
objects
table2.dat 89 3175 The narrow-line measurements of the T1 sample
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See also:
J/MNRAS/423/600 : Type-1 low-z AGN emission properties (Stern+, 2012)
J/MNRAS/426/2703 : Type 1 AGN at low z. II. (Stern+, 2012)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Object name (JHHMMSS.ss+DDMMSS.s)
21- 24 F4.1 [10-7W] logLbHa ?=-1 Broad Hα luminosity (erg/s)
26- 30 I5 km/s Dv FWHM of the fit (Δv)
32 A1 --- l_logM* Limit flag on logM*
33- 36 F4.1 [Msun] logM* ?=-1 Stellar mass
38 A1 --- l_logLUV Limit flag on logLUV
39- 42 F4.1 [10-7W] logLUV ?=-1 UV luminosity (erg/s)
44 A1 --- l_alpha Limit flag on alpha
45- 49 F5.2 --- alpha ?=-1 Spectra index αox, optical/x-ray
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- Name Object name (JHHMMSS.ss+DDMMSS.s)
21 A1 --- l_logLHb Limit flag on LHb
22- 25 F4.1 [10-7W] logLHb Luminosity of Hβ (erg/s)
27 A1 --- l_logL[OIII] Limit flag on L[OIII]
28- 31 F4.1 [10-7W] logL[OIII] Luminosity of [OIII] (erg/s)
33 A1 --- l_logLHa Limit flag on LHa
34- 37 F4.1 [10-7W] logLHa Luminosity of Hα (erg/s)
39 A1 --- l_logL[NII] Limit flag on L[NII]
40- 43 F4.1 [10-7W] logL[NII] Luminosity of [NII] (erg/s)
45 A1 --- l_logL[SII] Limit flag on L[SII]
46- 49 F4.1 [10-7W] logL[SII] ?=-1 Luminosity of [SII] (erg/s)
(-1 for "bad pixel")
51 A1 --- l_logL[OI] Limit flag on L[OI]
52- 55 F4.1 [10-7W] logL[OI] ?=-1 Luminosity of [OI] (erg/s)
(-1 for "bad pixel")
57 A1 --- fs [+x] non-robust spectrum flag (1)
59 A1 --- fa [+x] Stellar absorption flag (1)
61- 69 A9 --- BPT-[NII] Classification from [NII] BPT panel (2)
71- 78 A8 --- BPT-[SII] Classification from [SII] BPT panel (2)
80- 89 A10 --- BPT-[OI] Classification from [OI] BPT panel (2)
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Note (1): Flags as follows:
+ = robust result
x = Hα, Hβ or [NII] narrow-line measurements are not robust
(Section 2.2.3), or the Balmer lines are affected by strong stellar
absorption features (Section 2.2.4)
Note (2): Baldwin-Phillips-Terlevich classification (1981PASP...93....5B 1981PASP...93....5B) are:
AGN = pure AGN type
LINER = Low-Ionization Nuclear Emission-line Region
SF = star-forming galaxy
Seyfert = Active galaxy
Transition = Seyfert/LINER
Composite = composite region of the BPT diagram
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History:
* 25-Jun-2014: From electronic version of the journal
* 04-Nov-2014: Complete table1 restored
(the table was only 1854 rows before that date)
References:
Stern and Laor, Paper I 2012MNRAS.423..600S 2012MNRAS.423..600S, Cat. J/MNRAS/423/600
Stern and Laor, Paper II 2012MNRAS.426.2703S 2012MNRAS.426.2703S, Cat. J/MNRAS/426/2703
(End) Patricia Vannier [CDS] 09-May-2014