J/ApJS/258/38 Iron template spectrum from Mrk493 HST/STIS obs. (Park+, 2022)
A new iron emission template for active galactic nuclei.
I. Optical template for the Hβ region.
Park D., Barth A.J., Ho L.C., Laor A.
<Astrophys. J. Suppl. Ser., 258, 38 (2022)>
=2022ApJS..258...38P 2022ApJS..258...38P
ADC_Keywords: Galaxies, Seyfert; Spectra, optical; Ultraviolet; QSOs; Redshifts
Keywords: Supermassive black holes ; Seyfert galaxies ; Quasars ;
Active galaxies ; Active galactic nuclei
Abstract:
We present a new empirical template for iron emission in active
galactic nuclei (AGNs) covering the 4000-5600Å range. The new
template is based on a spectrum of the narrow-line Seyfert 1 galaxy
Mrk 493 obtained with the Hubble Space Telescope. In comparison with
the canonical iron template object I Zw 1, Mrk 493 has narrower
broad-line widths, lower reddening, and a less extreme Eddington
ratio, making it a superior choice for template construction. We
carried out a multicomponent spectral decomposition to produce a
template incorporating all the permitted and forbidden lines of FeII
identified in the Mrk 493 spectrum over this wavelength range, as well
as lines from TiII, NiII, and CrII. We tested the template by fitting
it to AGN spectra spanning a broad range of iron emission properties,
and we present a detailed comparison with fits using other widely used
monolithic and multicomponent iron emission templates. The new
template generally provides the best fit (lowest χ2) compared to
other widely used monolithic empirical templates. In addition, the new
template yields more accurate spectral measurements including a
significantly better match of the derived Balmer line profiles
(Hβ, Hγ, Hδ), in contrast with results obtained using
the other templates. Our comparison tests show that the choice of iron
template can introduce a systematic bias in measurements of the
Hβ line width, which consequently impacts single-epoch black hole
mass estimates by ∼0.1dex on average and possibly up to ∼0.3-0.5dex
individually.
Description:
We obtained UV and optical STIS spectra of Mrk 493 in HST program
GO-14744 (PI: Park) during 2017 August 28 and 31.
We used the G140L, G230L, G430L, and G750L gratings to cover the full
available wavelength range from 1150 to 10270Å. The spectral
resolving power for the G140L grating data is R∼2400, while it is
∼1500 for the other three.
Objects:
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RA (ICRS) DE Designation(s)
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15 59 09.62 +35 01 47.6 Mrk 493 = SDSS J155909.62+350147.4
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 20 801 Iron template spectrum
table2.dat 61 41 Test sample from the SDSS DR7 quasar catalog
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See also:
I/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/ApJS/145/199 : Optical spectroscopic atlas of low-z AGN (Marziani+, 2003)
J/ApJS/152/251 : Indo-US library of coude feed stellar spectra (Valdes+, 2004)
J/A+A/417/515 : I Zw 1 unusual emission line spectrum (Veron-Cetty+, 2004)
J/ApJ/670/92 : New sample of low-mass black holes in AGN (Greene+, 2007)
J/MNRAS/383/581 : Broad-line Balmer decrements in blue AGN (Dong+, 2008)
J/ApJ/687/78 : FeII emission in quasars (Hu+, 2008)
J/ApJ/680/169 : SDSS DR5 virial black hole masses (Shen+, 2008)
J/ApJ/674/668 : SDSS J102839.11+450009.4 Fe II emission lines (Wang+, 2008)
J/ApJS/189/15 : FeII emission in a sample of AGN spectra (Kovacevic+, 2010)
J/ApJ/736/86 : FeII emission in SDSS type 1 AGNs (Dong+, 2011)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/ApJ/746/169 : Luminosity function of broad-line quasars (Shen+, 2012)
J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)
J/ApJ/764/45 : Luminosity function of broad-line quasars. II. (Kelly+, 2013)
J/ApJ/793/108 : SEAMBHs. II. Continuum and Hbeta LCs (Wang+, 2014)
J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)
J/ApJ/809/20 : MBH-σ relation for active galaxies (Bennert+, 2015)
J/ApJ/837/131 : Space telescope RM project. V. NGC5548 sp. (Pei+, 2017)
J/ApJS/239/22 : NIR obs. of AGNs in COSMOS, SXDS & E-CDF-S (Schulze+, 2018)
J/ApJ/876/102 : Reverberation mapping of the Seyfert Zw I 1 (Huang+, 2019)
J/ApJ/887/135 : V-band, 5100Å and broad emission LCs of Mrk 79 (Lu+, 2019)
J/ApJ/886/93 : SAMP. III. Opt. LCs and spectra of two AGNs (Rakshit+, 2019)
J/ApJS/249/17 : SDSS QSO DR14 spectral properties (Rakshit+, 2020)
J/ApJS/253/20 : SEAMBHs XII. Reberberation mapping for 15 PG QSOs (Hu+, 2021)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 4 I4 0.1nm lambda [4000/5600] Wavelength; Angstroms
6- 12 F7.5 10-13W/m2/nm Flux [3e-05/0.75] Flux density;
in 10-15erg/s/cm2/Angstroms
14- 20 F7.5 10-13W/m2/nm e_Flux [0.0005/0.1] Uncertainty in Flux
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 3 A3 --- ID Object identifier (1)
5- 8 A4 --- --- [SDSS]
10- 28 A19 --- SDSS SDSS DR7 identifier (JHHMMSS.ss+DDMMSS.s)
30- 33 I4 --- Plate [276/2783] SDSS Plate number
35- 39 I5 --- MJD [51884/54584] Modified Julian Date
of SDSS observation
41- 43 I3 --- Fiber [4/639] SDSS Fiber number
45- 50 F6.4 --- z [0.06/0.6] Derived spectroscopic redshift
52- 56 I5 km/s FWHM [1303/11098] Full-Width at Half-Maximum
of broad Hβ line
58- 61 F4.2 --- RFeII [0.13/2.73] Ratio of equivalent widths of Fe
within 4435-4685Å to broad Hβ
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Note (1): To select AGN for our comparison tests, we first picked the object
that has the highest-S/N SDSS spectrum from within each grid cell,
giving a total of 35 objects (one grid cell did not contain any AGN in
the DR7 quasar catalog).
The selected objects are designated as A00, ... , A55, where the
initial letter A denotes the highest-S/N object in the grid cell (the
object with the second-highest S/N is denoted by the label "B"), and
the two digits represent the horizontal (RFeII) and vertical
(FWHMHβ) grid locations. See Section 5.1.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 17-May-2022