J/ApJ/736/86 FeII emission in SDSS type 1 AGNs (Dong+, 2011)
What controls the Fe II strength in active galactic nuclei?
Dong X.-B., Wang J.-G., Ho L.C., Wang T.-G., Fan X., Wang H., Zhou H.,
Yuan W.
<Astrophys. J., 736, 86 (2011)>
=2011ApJ...736...86D 2011ApJ...736...86D
ADC_Keywords: Active gal. nuclei ; Equivalent widths ; Spectra, ultraviolet ;
Galaxies, optical
Keywords: accretion, accretion disks - galaxies: active - line: formation -
quasars: emission lines - quasars: general
Abstract:
We used a large, homogeneous sample of 4178 z≤0.8 Seyfert 1 galaxies
and QSOs selected from the Sloan Digital Sky Survey to investigate the
strength of FeII emission and its correlation with other emission
lines and physical parameters of active galactic nuclei. We find that
the strongest correlations of almost all the emission-line intensity
ratios and equivalent widths (EWs) are with the Eddington ratio
(L/LEdd), rather than with the continuum luminosity at 5100Å
(L5100) or black hole mass (MBH); the only exception is the EW of
ultraviolet FeII emission, which does not correlate at all with
broad-line width, L5100, MBH, or L/LEdd. By contrast, the
intensity ratios of both the ultraviolet and optical FeII emission to
MgIIλ2800 correlate quite strongly with L/LEdd.
Interestingly, among all the emission lines in the near-UV and optical
studied in this paper (including MgIIλ2800, Hβ, and
[OIII]λ5007), the EW of narrow optical FeII emission has the
strongest correlation with L/LEdd. We hypothesize that the variation
of the emission-line strength in active galaxies is regulated by
L/LEdd because it governs the global distribution of the hydrogen
column density of the clouds gravitationally bound in the
line-emitting region, as well as its overall gas supply. The
systematic dependence on L/LEdd must be corrected when using the
FeII/MgII intensity ratio as a measure of the Fe/Mg abundance ratio to
study the history of chemical evolution in QSO environments.
Description:
We first construct a homogenous sample of Seyfert 1s and QSOs (namely
type 1 AGNs) from the spectral data set of the SDSS Fourth Data
Release (Adelman-McCarthy et al. 2006, Cat. II/267, superseded by Cat.
II/294). Our final sample consists of 4178 type 1 AGNs (hereinafter
the full type 1 sample). Of these, 2092 have redshifts z≳0.45 and
median S/N≳10/pixel in the UV FeII region (2200-3090Å): the UV
subsample.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 108 4178 Optical continuum and emission-line parameters
of the full sample
table2.dat 66 2092 Near-UV continuum and emission-line parameters
of the UV subsample
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
J/other/RMxAA/47.361 : AGN activity in isolated SDSS galaxies (Coziol+, 2011)
J/ApJ/692/758 : BAL QSOs in SDSS-DR5 (Gibson+, 2009)
J/MNRAS/354/L25 : MgII absorbers in SDSS QSOs (Bouche+, 2004)
J/AJ/124/3042 : Seyfert 1 galaxies from SDSS EDR (Williams+, 2002)
J/ApJS/143/257 : AGN emission line properties (Kuraszkiewicz+, 2002)
http://www.sdss.org/ : SDSS home page
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
21- 26 F6.4 --- z [0.02/0.8] SDSS redshift
28- 32 F5.2 [10-7W] logL510 [42.83/46.09] Log luminosity at 5100Å (1)
34- 38 F5.2 --- beta [-2.5/0.88] Local continuum slope β (2)
40- 44 I5 km/s FWHM(Hb) [999/19251] FWHM of broad Hβ (3)
46 A1 --- l_logFeIIn Limit flag on logFeIIn
47- 52 F6.2 [mW/m2] logFeIIn Log of narrow FeII 4570Å line flux (4)
54 A1 --- l_W(FeIIn) Limit flag on W(FeIIn)
55- 58 F4.1 0.1nm W(FeIIn) Rest-frame narrow FeII 4570Å equivalent
width (5)
60 A1 --- l_logFeIIb Limit flag on logFeIIb
61- 66 F6.2 [mW/m2] logFeIIb Log of broad FeII 4570Å line flux (4)
68 A1 --- l_W(FeIIb) Limit flag on W(FeIIb)
69- 73 F5.1 0.1nm W(FeIIb) Rest-frame broad FeII 4570Å equivalent
width (5)
75- 80 F6.2 [mW/m2] logHb.n ? Log of narrow Hβ line flux (6)
82- 87 F6.2 [mW/m2] logHb.b Log of broad Hβ line flux (6)
89- 93 F5.1 0.1nm W(Hb.b) Rest-frame broad Hβ equivalent width (5)
95 A1 --- l_logOIII Limit flag on logOIII
96-101 F6.2 [mW/m2] logOIII Log of [OIII] 5007Å line flux (6)
103 A1 --- l_W(OIII) Limit flag on W(OIII)
104-108 F5.1 0.1nm W(OIII) Rest-frame [OIII] 5007Å EW (5)
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Note (1): Of the power-law continuum in erg/s.
Note (2): Fitted in the rest-frame wavelength range of 4000-5600 Angstroms
(fλ=λβ).
Note (3): Corrected for instrumental broadening.
Note (4): Integrated in the range of 4434-4684 Angstroms from
the best-fit model. In units of erg/s/cm2.
Note (5): In units of Angstroms.
Note (6): In units of erg/s/cm2.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.2 [10-7W] logL300 [44.3/46.41] Log luminosity at 3000Å (1)
27- 31 I5 km/s FWHM(Mg) [891/14316] FWHM of broad MgII 2800Å (2)
33 A1 --- l_logFeII Limit flag on logFeII
34- 39 F6.2 [mW/m2] logFeII [-14.34/-12.3] Log of UV FeII emission (3)
41 A1 --- l_W(FeII) Limit flag on W(FeII)
42- 46 F5.1 0.1nm W(FeII) Rest-frame UV FeII equivalent width (4)
48- 53 F6.2 [mW/m2] logMgIIn Log of narrow MgII 2800Å line flux (5)
55- 60 F6.2 [mW/m2] logMgIIb Log of broad MgII 2800Å line flux (5)
62- 66 F5.1 0.1nm W(MgIIb) Rest-frame MgII 2800Å equivalent width (4)
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Note (1): Of the power-law continuum in erg/s.
Note (2): Corrected for instrumental broadening.
Note (3): Integrated in the range of 2200-3090 Angstroms from
the best-fit model. In units of erg/s/cm2.
Note (4): In units of Angstroms.
Note (5): In units of erg/s/cm2.
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 12-Dec-2012