J/ApJ/966/5 Halpha, g- and r- ZTF light curves of AGNs (Ma+, 2024)
Hα time delays of active galactic nuclei from the Zwicky Transient
Facility broadband photometry.
Ma Q., Wen Y., Wu X.-B., Gu H., Fu Y.
<Astrophys. J., 966, 5 (2024)>
=2024ApJ...966....5M 2024ApJ...966....5M
ADC_Keywords: Active gal. nuclei; Photometry; Optical
Keywords: Active galactic nuclei ; Reverberation mapping ;
Supermassive black holes
Abstract:
In our previous work on broadband photometric reverberation mapping
(PRM), we proposed the interpolated cross-correlation function
(ICCF)-Cut process to obtain the time lags of the Hα emission
line from two broadband lightcurves via subtracting the continuum
emission from the line band. Extending the work, we enlarge our sample
to the Zwicky Transient Facility (ZTF) database. We adopt two criteria
to select 123 type 1 active galactic nuclei (AGNs) with sufficient
variability and smooth light curves from 3537 AGNs at z<0.09 with more
than 100 epoch observations in the g and r bands from the ZTF
database. We calculate the Hα time lags for 23 of them that have
previous spectroscopic reverberation mapping (SRM) results using the
ICCF-Cut, Just Another Vehicle for Estimating Lags In Nuclei
(JAVELIN), and χ2 methods. Our obtained Hα time lags are
slightly larger than the Hβ time lags, which is consistent with
the previous SRM results and the theoretical model of the AGN
broad-line region. The comparisons between the SRM and PRM lag
distributions and between the subtracted emission line light curves
indicate that after selecting AGNs with the two criteria, combining
the ICCF-Cut, JAVELIN, and χ2 methods provides an efficient way to
get the reliable Hα lags from the broadband PRM. Such techniques
can be used to estimate the black hole masses of a large sample of
AGNs in large multiepoch photometric sky surveys such as the Legacy
Survey of Space and Time and the survey from the Wide Field Survey
Telescope in the near future.
Description:
In this work, we use the data of the Zwicky Transient Facility (ZTF)
DR16 between 2018 March and 2023 January.
ZTF is a time-domain survey that had its first light at Palomar
Observatory in 2017. By scanning more than 3750 square degrees of the
sky per hour to a depth of 20.5 mag, ZTF can produce a photometric
variability catalog with nearly 300 observational epochs each year.
Same as Paper I (Ma+ 2023ApJ...949...22M 2023ApJ...949...22M), we use three methods,
namely, the interpolated cross-correlation function (ICCF)-Cut
(https://github.com/PhotoRM/ICCF-Cut), Just Another Vehicle for
Estimating Lags In Nuclei (JAVELIN, Zu+ 2016ApJ...819..122Z 2016ApJ...819..122Z), and x2
methods, to calculate the time lags to ensure the reliabilities of the
time lags.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 44 69 List of 23 selected AGNs
lcs/* . 81 *Host-subtracted continuum band g and r lightcurves
and extracted Halpha light curves for each AGN
(in MRT format; data behind Figures 4-13, B1-B8,
C1-C10)
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Note on lcs/* : These files can be read in python using the astropy package:
from astropy.table import Table
data = Table.read("example.mrt", format="ascii.cds")
or with the most recent version of TOPCAT (> Version 4.8)
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See also:
V/162 : LAMOST DR11 catalogs (Luo+, 2026)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJ/716/993 : LAMP: reverberation mapping of H and He lines (Bentz+, 2010)
J/ApJ/756/73 : gri LCs of the low-luminosity AGN NGC 4395 (Edri+, 2012)
J/ApJ/755/60 : Reverberation mapping for 5 Seyfert 1 galaxies (Grier+, 2012)
J/ApJ/851/21 : SDSS RM project first year of observations (Grier+, 2017)
J/ApJ/850/74 : Swift/BAT AGN Spectroscopic Survey. I. (Koss+, 2017)
J/ApJ/869/142 : Monitoring AGNs with Hβ Asymmetry (MAHA). I. (Du+, 2018)
J/A+A/620/A137 : CCD B,V,R,I,Ha photometry of 3C120 (Ramolla+, 2018)
J/ApJ/886/42 : Reverberation mapping & opt. spectra data of AGNs (Du+, 2019)
J/ApJS/253/20 : SEAMBHs XII. Reberberation mapping for 15 PG QSOs (Hu+, 2021)
J/ApJ/918/50 : Reverberation mapping for Mrk 817 and NGC 7469 (Lu+, 2021)
J/ApJS/262/14 : AGNs with Hβ asymmetry. III. 15 PG quasars (Bao+, 2022)
J/ApJ/940/20 : z<0.8 AGNs from MQC with robust lags from ZTF (Guo+, 2022)
J/ApJS/263/10 : 2015, 2018-2021 sp. monitoring of NGC 5548 (Lu+, 2022)
J/ApJ/925/52 : LAMP 2016: velocity-resolved Hb lags in Seyfert (U+, 2022)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 14 A14 --- Name AGN name
16- 20 F5.3 --- z [0.016/0.09] Redshift
22- 25 F4.2 --- J [1.16/4.7] J index
27- 31 F5.2 10+5s-2 s [3.5/73.4] Smoothness of the light curve
33- 37 I5 --- J/s [4822/50126] Ratio of J to s
39- 44 A6 --- File Filter indication for the light curve file;
column added by CDS
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 03-Aug-2026