J/ApJS/282/56 Supermassive BH with high accretion rates. XV. MgII (Bai+, 2026)
Supermassive black holes with high accretion rates in active galactic nuclei.
XV. Reverberation mapping of MgII emission lines.
Bai H.-R., Du Pu, Hu C., Chen Y.-J., Yao Z.-H., Li Y.-R., Fu Y.-X.,
Wang Y.-L., Zhao Yu, Zhang H., Liu J.-R., Yang S., Peng Y.-C., Fang F.-N.,
Songsheng Y.-Y., Xiao M., Zhai S., Li S.-S., Lu K.-X., Zhang Z.-X.,
Bao D.-W., Guo W.-J., Feng J.-Q., Zhao Y.-P., Aceituno J., Bai J.-M.,
Ho L.C., Wang J.-M., SEAMBH Collaboration
<Astrophys. J. Suppl. Ser., 282, 56 (2026)>
=2026ApJS..282...56B 2026ApJS..282...56B
ADC_Keywords: Active gal. nuclei; Black holes; Spectra, optical; Photometry;
Redshifts
Keywords: Active galactic nuclei ; Quasars ; Supermassive black holes ;
Reverberation mapping
Abstract:
As the 15th paper in a series reporting on a large reverberation
mapping (RM) campaign of super-Eddington accreting massive black holes
(SEAMBHs) in active galactic nuclei (AGNs), we present the results of
measurements of the MgII lines in 18 SEAMBHs monitored
spectroscopically from 2017 to 2024. Among these, the time lags of
MgII have been successfully determined for eight of the 18 objects,
thereby expanding the current Mg ii RM sample, particularly at higher
accretion rates. By incorporating measurements of the line widths, we
determine the masses of their central supermassive black holes. Based
on these new measurements, we update the relation between the MgII
radius and the monochromatic luminosity at 3000Å (RMgII-L3000
relation), yielding a slope of 0.24±0.03, which is slightly
shallower than, yet still consistent with, previously reported values.
Similar to the Hβ lines, the Mg ii time lags in SEAMBHs are
shorter than those of AGNs with normal accretion rates at comparable
luminosities. The deviation of AGNs from the best-fit RMgII-L3000
relation shows a strong correlation with the accretion rate, while no
significant correlation is found between the deviation and the flux
ratio of UV iron to MgII.
Description:
The MgII campaign started from the fall of 2017. Spectroscopic and
photometric observations of 12 targets were conducted using the
Lijiang 2.4m telescope at the Yunnan Observatories of the Chinese
Academy of Sciences.
Additionally, observations of six other targets were carried out at
the 2.2m telescope of the Calar Alto Astronomical Observatory, part of
the Centro Astronomico Hispano en Andalucia (CAHA) in Spain.
Data were collected using the Yunnan Faint Object Spectrograph and
Camera (YFOSC) mounted on the Lijiang 2.4m telescope, and the Calar
Alto Faint Object Spectrograph (CAFOS) on the CAHA 2.2m telescope.
We used Grism 3 at Lijiang, which provided a wavelength coverage of
3400-9100Å and a dispersion of 2.9Å/pixel, and Grism G-200 at
CAHA, which covered a wavelength range of 4000-8500Å with a
dispersion of 4.47Å/pixel. The typical exposure time for each
observation was 1800s.
As a double check on the accuracy of the flux calibration for the
spectroscopic observations and to ensure that the comparison stars did
not exhibit significant variability during the campaign, we also
conducted photometric observations of the targets and comparison
stars. We obtained three broadband photometric images of the targets
just prior to the spectral exposures each night, with typical exposure
times of 80s for each image. The filters used at Lijiang and CAHA are
provided in Table 1.
To supplement and extend the coverage of the continuum light curves,
we utilized archival time-domain photometric data from the Zwicky
Transient Facility (ZTF g, r, i).
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 98 18 Objects and observations
table2.dat 93 1317 Light curves
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See also:
J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004)
J/ApJS/152/251 : Indo-US library of coude feed stellar spectra (Valdes+, 2004)
J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)
J/ApJ/687/78 : FeII emission in quasars (Hu+, 2008)
J/ApJ/680/169 : SDSS DR5 virial black hole masses (Shen+, 2008)
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/755/60 : Reverberation mapping for 5 Seyfert 1 galaxies (Grier+, 2012)
J/ApJ/753/125 : NIR spectroscopy follow-up of 60 SDSS-DR7 QSOs (Shen+, 2012)
J/ApJ/782/45 : SEAMBHs. I. Mrk 142, Mrk 335, and IRAS F12397+3333 (Du+, 2014)
J/A+A/562/A34 : UV FeII template from LBQS 2113-4538 (Hryniewicz+, 2014)
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/806/22 : SEAMBHs IV. Hβ time lags (Du+, 2015)
J/ApJ/825/126 : SEAMBHs. V. The third year (Du+, 2016)
J/ApJ/818/L14 : RM AGNs accretion rates and BH masses (Du+, 2016)
J/ApJ/821/56 : Space telescope RM project. III. NGC5548 (Fausnaugh+, 2016)
J/ApJ/818/30 : Lag measurements for z<0.8 QSOs from the SDSS-RM (Shen+, 2016)
J/ApJ/843/30 : MgII line vs 3000Å cont. analysis in 68 QSOs (Zhu+, 2017)
J/ApJ/866/133 : Continuum-Hβ light curves of 5 Seyfert 1 (De Rosa+, 2018)
J/ApJ/869/142 : Monitoring AGNs with Hβ Asymmetry (MAHA). I. (Du+, 2018)
J/ApJ/856/6 : SEAMBHs IX. 10 new Hβ light curves (Du+, 2018)
J/ApJ/865/56 : Emission line & R-band continuum LCs of 17 QSOs (Lira+, 2018)
J/ApJ/880/46 : Spectroscopy & V-band monitoring of CTS C30.10 (Czerny+, 2019)
J/ApJ/886/42 : Reverberation mapping & opt. spectra data of AGNs (Du+, 2019)
J/ApJS/241/34 : The SDSS Reverberation Mapping (SDSS-RM) project (Shen+, 2019)
J/ApJ/901/55 : SDSS-RM project: MgII lags from 4yrs obs. (Homayouni+, 2020)
J/ApJ/903/86 : 68 active galactic nuclei properties (Martinez-Aldama+, 2020)
J/ApJS/253/20 : SEAMBHs XII. Reberberation mapping for 15 PG QSOs (Hu+, 2021)
J/ApJ/925/52 : LAMP 2016: velocity-resolved Hb lags in Sy galaxies (U+, 2022)
J/ApJS/278/61 : Supermassive BH with accretion rates in AGN. XIV. (Hu+, 2025)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS Object SDSS name (JHHMMSS.ss+DDMMSS.s)
26- 29 F4.2 --- z [0.7/0.9] Redshift
31- 37 A7 --- Obs Name of observatory (Lijiang or CAHA)
39- 45 A7 --- Filt Filter used for the photometric observations
47- 53 A7 "Y/M" Start Start date of monitoring at Lijiang and CAHA
54 A1 --- --- [-]
55- 61 A7 "Y/M" End End date of monitoring at Lijiang and CAHA
63- 65 I3 --- Nsp [36/107] Number of spectroscopic epochs
67- 68 I2 d Tmed [14/21] Median sampling cadence
70- 73 I4 d Dur [1467/2408] Total duration of the entire
spectroscopic monitoring period
75- 76 I2 h RACh Comparison star hour of right ascension (J2000)
(1)
78- 79 I2 min RACm Comparison star minute of right ascension (J2000)
81- 85 F5.2 s RACs Comparison star second of right ascension (J2000)
87 A1 --- DEC- Comparison star sign of declination (J2000) (1)
88- 89 I2 deg DECd Comparison star degree of declination (J2000) (1)
91- 92 I2 arcmin DECm Comparison star arcminute of declination (J2000)
94- 98 F5.2 arcsec DECs Comparison star arcsecond of declination (J2000)
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Note (1): Coordinates of the comparison star used in the spectroscopic
observations.
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 A4 --- --- [SDSS]
6- 24 A19 --- SDSS Object SDSS name (JHHMMSS.ss+DDMMSS.s)
26- 32 A7 --- SName Short name used in this work (JHHMMSS)
34- 44 F11.3 d JDphot ? Julian date of photometric
observation
46- 50 F5.3 10-16cW/m2/nm Fphot [2/8.9]? Flux, photometric continuum,
10-16erg/s/cm2/Å
52- 56 F5.3 10-16cW/m2/nm e_Fphot [0.014/0.9]? Uncertainty in Fphot
58- 68 F11.3 d JDspec ? Julian date of spectroscopic
observation
70- 74 F5.3 10-16cW/m2/nm F3000 [2.16/8.7]? Flux, spectroscopic
continuum, 10-16erg/s/cm2/Å
76- 80 F5.3 10-16cW/m2/nm e_F3000 [0.05/0.4]? Uncertainty in F3000
82- 87 F6.3 10-15mW/m2 FMgII [4/18.7]? Flux, MgII line,
10-15erg/s/cm2
89- 93 F5.3 10-15mW/m2 e_FMgII [0.05/1.1]? Uncertainty in FMgII
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History:
From electronic version of the journal
License: CC-BY-4.0
References:
Du et al. Paper I. 2014ApJ...782...45D 2014ApJ...782...45D Cat. J/ApJ/782/45
Wang et al. Paper II. 2014ApJ...793..108W 2014ApJ...793..108W Cat. J/ApJ/793/108
Hu et al. Paper III. 2015ApJ...804..138H 2015ApJ...804..138H
Du et al. Paper IV. 2015ApJ...806...22D 2015ApJ...806...22D Cat. J/ApJ/806/22
Du et al. Paper V. 2016ApJ...825..126D 2016ApJ...825..126D Cat. J/ApJ/825/126
Du et al. Paper VI. 2016ApJ...820...27D 2016ApJ...820...27D
Xiao et al. Paper VII. 2018ApJ...864..109X 2018ApJ...864..109X
Li et al. Paper VIII. 2018ApJ...869..137L 2018ApJ...869..137L
Du et al. Paper IX. 2018ApJ...856....6D 2018ApJ...856....6D Cat. J/ApJ/856/6
Lu et al. Paper X. 2019ApJ...877...23L 2019ApJ...877...23L Cat. J/ApJ/877/23
Cackett et al. Paper XI. 2020ApJ...896....1C 2020ApJ...896....1C Cat. J/ApJ/896/1
Hu et al. Paper XII. 2021ApJS..253...20H 2021ApJS..253...20H Cat. J/ApJS/253/20
Khatu et al. Paper XIII. 2023ApJ...958..127K 2023ApJ...958..127K Cat. J/ApJ/958/127
Hu et al. Paper XIV. 2025ApJS..278...61H 2025ApJS..278...61H Cat. J/ApJS/278/61
Bai et al. Paper XV. 2026ApJS..282...56B 2026ApJS..282...56B This catalog
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 24-Jul-2026