J/ApJ/887/15 Xinglong spectra of two changing-look SDSS AGNs (Wang+, 2019)
Two new "turn-off" changing-look active galactic nuclei and implication on
"partially obscured" AGNs.
Wang J., Xu D.W., Wang Y., Zhang J.B., Zheng J., Wei J.Y.
<Astrophys. J., 887, 15 (2019)>
=2019ApJ...887...15W 2019ApJ...887...15W
ADC_Keywords: Active gal. nuclei; Spectra, optical; QSOs
Keywords: Active galactic nuclei ; Quasars ; Astrophysical masers
Abstract:
We report a spectroscopic identification of two new changing-look
active galactic nuclei (CL-AGNs): SDSSJ104705.16+544405.8 and
SDSSJ120447.91+170256.8, both with a "turn-off" type transition from
type-1 to type-1.8/1.9. The identification is arrived at through a
follow-up spectroscopic observation of the five CL-AGNs candidates
that are extracted from the sample recently released in
MacLeod+ (2019, J/ApJ/874/8). The candidates are extracted by the
authors from the Sloan Digit Sky Survey Data Release 7, and are
spectroscopically confirmed quasars with large amplitude variability.
By compiling a sample of 26 previously identified CL-AGNs, we confirm
the claim by MacLeod+ that CL-AGNs tend to be biased against a low
Eddington ratio, and identify an overlap between the CL-AGNs at their
dim state and the so-called intermediate-type AGNs. The overlap
implies that there two populations of the intermediate-type AGNs with
different origins. One is due to the torus orientation effect, and the
other to the intrinsic change of the accretion rate of the central
supermassive black holes.
Description:
Our spectroscopic observations were carried out using the 2.16m
telescope at Xinglong Observatory of National Astronomical
Observatories, Chinese Academy of Sciences (NAOC) in several runs.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 48 12 Log of spectroscopic observation for
five candidates selected
in MacLeod et al. 2019, J/ApJ/874/8
zd1047.dat 30 1558 Xinglong spectrum of SDSS J104705.16+544405.8
(Data behind Figure 1)
zd1204.dat 30 1753 Xinglong spectrum of SDSS J120447.91+170256.8
(Data behind Figure 1)
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See also:
III/116 : Spectrophotometric Standards (Massey+ 1988)
VI/64 : Recombination line intensities for hydrogenic ions (Storey+ 1995)
V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
J/A+A/417/515 : I Zw 1 unusual emission line spectrum (Veron-Cetty+, 2004)
J/ApJS/166/128 : Narrow line Seyfert 1 galaxies from SDSS-DR3 (Zhou+, 2006)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 2014)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJ/793/108 : SEAMBHs. II. Continuum and Hbeta LCs (Wang+, 2014)
J/ApJ/806/22 : SEAMBHs IV. Hβ time lags (Du+, 2015)
J/ApJS/234/16 : Halpha & Hbeta spectral regions of low-z QSOs (Chen+, 2018)
J/ApJ/854/160 : SDSS & DES long-term variability QSOs (Rumbaugh+, 2018)
J/ApJ/874/8 : Follow-up spec. of SDSS changing-look QSOs (Macleod+, 2019)
J/ApJ/883/94 : Opt. and UV follow-up of 1ES 1927+654 (Trakhtenbrot+, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- SDSS SDSS name (JHHMMSS.ss+DDMMSS.s)
21- 25 F5.3 --- z [0.21/0.61] Redshift
27- 31 F5.2 mag gmag [16.19/18.07] SDSS g-band (AB) magnitude
33- 43 A11 "Y/M/D" Date Date of observation (UT)
45- 48 I4 s Exp [2400/7200] Total exposure time
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Byte-by-byte Description of file: zd1047.dat zd1204.dat
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Bytes Format Units Label Explanations
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1- 16 F16.11 0.1nm lambda [2963.8/7180.3] Spectrum wavelength
in Angstrom units
18- 30 E13.8 cW/m2/nm Flux [-4e-17/8.4e-16] Flux
in erg/s/cm2/Å units
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-May-2021