J/ApJS/276/51 Long-term spectroscopic monitoring of Mrk 1018 (Lu+, 2025)
A short-lived rejuvenation during the decades-long changing-look transition in
the nucleus of Mrk 1018.
Lu K.-X., Li Y.-R., Wu Q., Ho L.C., Zhang Z.-X., Feng H.-C., Li S.-S.,
Chen Y.-J., Sun M., Shu X., Guo W.-J., Cheng C., Wang J.-G., Kim D.,
Wang J.-M., Bai J.-M.
<Astrophys. J. Suppl. Ser., 276, 51 (2025)>
=2025ApJS..276...51L 2025ApJS..276...51L
ADC_Keywords: Active gal. nuclei; Spectra, optical
Keywords: Active galactic nuclei ; Supermassive black holes ; Accretion ;
Time domain astronomy ; Reverberation mapping
Abstract:
Changing-look active galactic nuclei (CL-AGNs), characterized by the
emergence or disappearance of broad lines accompanied by extreme
continuum flux variability, have drawn much attention for their
potential to reveal physical processes underlying AGN evolution. We
perform seven-season spectroscopic monitoring on Mrk1018, one of the
earliest identified CL-AGN. Around 2020, we detect a full-cycle
changing-look transition of Mrk 1018 within one year, associated with
a nucleus outburst, which likely arose from the disk instability in
the transition region between the outer standard rotation- dominated
disk and inner advection-dominated accretion flow. Over the past 45
years, the accretion rate of Mrk 1018 changed 1000 times and the
maximum Eddington ratio reached 0.02. By investigating the relation
between the broad- line properties and the Eddington ratio
(Lbol/LEdd), we find strong evidence that the full-cycle-type
transition is regulated by accretion. There exists a turnover point in
the Balmer decrement, which is observed for the first time. The broad
Balmer lines change from a single peak in Types 1.0-1.2 to double
peaks in Types 1.5-1.8, and the double-peak separation decreases with
increasing accretion rate. We also find that the FWHM of the broad
Balmer lines obeys FWHM∝(Lbol/LEdd)-0.27, as expected for a
virialized broad-line region (BLR). The velocity dispersion
σline follows a similar trend in Types 1.5-1.8 but displays a
sharp increase in Types 1.0-1.2, resulting in a dramatic drop in
FWHM/σline. These findings suggest that a virialized BLR
together with accretion-dependent turbulent motions might be
responsible for the diversity of BLR phenomena across the AGN
population.
Description:
Long-term spectroscopic observations of Mrk 1018 were conducted
utilizing the Yunnan Faint Object Spectrograph and Camera (YFOSC)
attached to the Lijiang 2.4m telescope (LJT).
For spectroscopy of Mrk 1018, Grism 14 was employed, which spans
wavelengths from approximately ∼3600Å to 7460Å and offers a
dispersion of 1.8Å/pixel.
The spectroscopic monitoring of Mrk 1018 started on 2017 November 5,
and to date, seven-season observations have been conducted from
2017 November to 2024 February (with Modified Julian Days ranging from
58063 to 60324).
To obtain the long-term variability of Mrk 1018, we compiled the
photometry data from the public archival database of Zwicky Transient
Facility (ZTF; Graham+ 2019PASP..131g8001G 2019PASP..131g8001G) and Asteroid
Terrestrial-impact Last Alert System (ATLAS; Tonry+ 2018PASP..130f4505T 2018PASP..130f4505T).
We use the ZTF g- and r-band data, along with the ATLAS c- and o-band
data, and combine them.
Mrk 1018 is also covered by the Wide-field Infrared Survey Explorer
(WISE; see II/328) survey.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
02 06 15.98 +00 17 29.2 Mrk 1018 = Z 387-34
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 37 105 Fluxes of broad Balmer lines
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See also:
II/294 : The SDSS Photometric Catalog, Release 7 (Adelman-McCarthy+, 2009)
VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009)
II/328 : AllWISE Data Release (Cutri+ 2013)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
J/AJ/126/1720 : ugriz and Hα of double-peaked AGN (Strateva+, 2003)
J/ApJ/613/682 : AGN masses & broad-line region sizes (Peterson+, 2004)
J/A+A/417/515 : I Zw 1 unusual emission line spectrum (Veron-Cetty+, 2004)
J/ApJ/716/993 : LAMP: reverberation mapping of H and He lines (Bentz+, 2010)
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/ApJ/739/57 : Ultra hard X-ray AGNs in the Swift/BAT survey (Koss+, 2011)
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)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJS/217/26 : Lick AGN monitoring 2011: light curves (Barth+, 2015)
J/ApJ/825/126 : SEAMBHs. V. The third year (Du+, 2016)
J/MNRAS/455/2918 : Phot. & line luminosities for ASASSN-14li (Holoien+, 2016)
J/ApJ/851/21 : SDSS RM project first year of observations (Grier+, 2017)
J/ApJ/856/6 : SEAMBHs IX. 10 new Hβ light curves (Du+, 2018)
J/ApJ/859/116 : BH masses and Eddington ratios of Type 2 QSOs (Kong+, 2018)
J/ApJ/887/135 : V-band, 5100Å & broad emission LCs of Mrk 79 (Lu+, 2019)
J/ApJ/883/94 : Optical & UV follow-up of 1ES 1927+654 (Trakhtenbrot+, 2019)
J/MNRAS/491/4925 : Changing-state quasars with CRTS (Graham+, 2020)
J/ApJ/905/75 : 3yrs spectroscopic light curves of PG0026+129 (Hu+, 2020)
J/ApJ/912/92 : Lijiang/YFOSC light curves of NGC 2617 (Feng+, 2021)
J/ApJ/918/50 : Reverberation mapping for Mrk 817 and NGC 7469 (Lu+, 2021)
J/ApJS/263/10 : 2015, 2018-2021 sp. monitoring of NGC 5548 (Lu+, 2022)
J/ApJS/258/38 : Iron template sp. from Mrk493 HST/STIS obs. (Park+, 2022)
J/ApJS/272/13 : Changing-look AGN. I. (Panda+, 2024)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1 I1 --- Set [1/2] Observation period;
1=previous observations or 2=seven-season
3- 11 F9.3 d JD [44097.5/60324] Observation date, JD-2400000
13- 18 F6.3 10-17W.m-2 FHb [0.001/20.6] Broad Hβ flux,
10-14erg/s/cm2
20- 24 F5.3 10-17W.m-2 e_FHb [0.05/0.2] Uncertainty in FHb
26- 31 F6.3 10-17W.m-2 FHa [0.01/41] Broad Hα flux,
10-14erg/s/cm2
33- 37 F5.3 10-17W.m-2 e_FHa [0.08/0.4] Uncertainty in FHa
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 22-Jan-2026