J/ApJ/968/59 LCs and time lag measurements of type 1 AGNs (Mandal+, 2024)
Revisiting the dust torus size-luminosity relation based on a uniform
reverberation-mapping analysis.
Mandal A.K., Woo J.-H., Wang S., Rakshit S., Cho H., Son D., Stalin C.S.
<Astrophys. J., 968, 59 (2024)>
=2024ApJ...968...59M 2024ApJ...968...59M
ADC_Keywords: Active gal. nuclei; Photometry, infrared; Optical; Redshifts;
Surveys
Keywords: Reverberation mapping ; Black holes ; Active galactic nuclei ; Quasars
Abstract:
We investigate the torus size-luminosity relation of Type 1 active
galactic nuclei (AGNs) based on the reverberation-mapping analysis
using the light curves of the optical continuum and the IR continuum
obtained with the W1 and W2 bands of the Wide-field Infrared Survey
Explorer survey. The final sample consists of 446 and 416 AGNs,
respectively, for W1- and W2-band light curves, covering a large
dynamic range of bolometric luminosity from 1043.4 to 1047.6erg/s,
which show reliable lag measurements based on our quality assessment
analysis. After correcting for the accretion disk contamination in the
observed IR flux, we constrain the torus size (Rdust) and AGN
bolometric luminosity (Lbol) relationship with the best-fit slope of
0.39 (0.33) for the W1 (W2) band, which is shallower than expected
from the dust radiation equilibrium model. By combining the previous
K-band lag measurements, we find that the measured torus size depends
on the observed wavelength of the dust radiation, as
Rdust,K:Rdust,W1:Rdust,W2=1.0:1.5:1.8
(Rdust∝λ0.80) at Lbol=1046erg/s, confirming a
stratified structure of the torus, where wavelength-dependent
emissions originate from distinct regions of the torus. By
investigating the deviation from the best-fit torus size-luminosity
relation, we find a moderate correlation between the offset from the
Rdust-Lbol relation and Eddington ratio. This suggests a possible
influence of the Eddington ratio on the observed flattening of the
Rdust-Lbol relationship.
Description:
We selected targets from two distinct categories based on their
redshifts and luminosities.
Sample 1: To explore the low-luminosity end of the Rdust-LAGN
relationship, we selected targets from the catalog of
Liu+ (2019, J/ApJS/243/21). This catalog comprises a uniformly defined
sample of 14,584 Type 1 AGNs compiled from SDSS DR7 at z<0.35 and
covering a range of AGN bolometric luminosities between 1041.5 and
1046.6erg/s.
See Section 2.1.
Sample 2: To cover a moderate- to high-luminosity range in the
Rdust-LAGN relationship, we used the SDSS S82 region
(MacLeod+ 2012, J/ApJ/753/106), where a total of approximately 9258
spectroscopically confirmed broad-line AGNs are available.
See Section 2.2.
For Sample 1, we compiled the available optical photometric data from
different ground-based transient surveys. Initially, we conducted a
search for data from the ASAS-SN survey, as it overlaps with the major
part of the IR light curves from WISE and Near-Earth Object Wide-field
Infrared Survey Explorer (NEOWISE). Since 2012, ASAS-SN monitored
nearly the entire visible sky to a V-band depth of 17 mag with a
cadence of 2-3 days using 20 telescopes, each of 14cm diameter.
We also collected V-band photometric light-curve data for the
142 targets having ASAS-SN data from the CRTS. This survey uses the
0.7m Catalina Schmidt Telescope in Tucson, AZ, the 1.5m telescope on
Mt. Lemmon, AZ, and the 0.5m Siding Springs Survey telescope in
Australia to search for optical transients with timescales of minutes
to years in the northern sky.
In addition, we obtained photometric light-curve data from the PTF
Data Release (DR) 3 when available. This survey used the 48 inch
Samuel Oschin Telescope at the Palomar Observatory in northern San
Diego County, CA.
Finally, we gathered light-curve data from the ZTF DR14. ZTF is a
wide-field time-domain survey, which uses the 1.2m Schmidt telescope
at the Palomar Observatory with 47deg2 field of view. It provides
photometric light-curve data with a cadence of 3-4 days in the gri
bands since 2018 March (MJD∼58194).
In summary, we collected optical photometric light-curve data for
142 Type 1 AGNs in Sample 1 with a baseline from 2005 to 2021.
We utilized the publicly available light-curve data in the optical
band from Yang+ (2020, J/ApJ/900/58) for 587 Type 1 AGNs in Sample 2
for our own analysis.
WISE surveys the full sky at wavelengths centered at 3.4 (W1),
4.6 (W2), 12 (W3), and 22um (W4) using a 40cm diameter infrared
telescope since 2010. We collected profile-fit photometric light-curve
data of our targets in the W1 and W2 bands from the Near-Earth Object
Wide-field Infrared Survey Explorer Reactivation Database, WISE
All-Sky, and WISE Post-Cryo Database from the NASA/IPAC Infrared
Science Archive. The retrieved WISE data cover a time period from
2010 to 2020.
See Section 2.3.2.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table3a.dat 43 99343 Optical light curves
table3b.dat 42 14472 Observed IR light curves in W1 and W2 bands
table3c.dat 42 14472 Accretion disk (AD) contamination corrected
IR light curves in W1 and W2 bands
table4.dat 162 478 Results of the time lag measurements for the
finally selected sample
--------------------------------------------------------------------------------
See also:
II/313 : Palomar Transient Factory (PTF) photometric catalog 1.0 (Ofek+, 2012)
II/311 : WISE All-Sky Data Release (Cutri+ 2012)
II/357 : The Dark Energy Survey (DES): Data Release 1 (Abbott+, 2018)
V/154 : Sloan Digital Sky Surveys (SDSS), Release 16 (DR16) (Ahumada+, 2020)
VII/289 : SDSS quasar catalog, sixteenth data release (DR16Q) (Lyke+, 2020)
II/371 : The Dark Energy Survey (DES): Data Release 2 (Abbott+, 2021)
II/389 : The Pan-STARRS release 1 (PS1) Survey - DR2 (Magnier+, 2025)
J/ApJS/95/1 : Atlas of Quasar Energy Distributions (Elvis+ 1994)
J/A+A/333/231 : O-M stars model atmospheres (Bessell+ 1998)
J/ApJ/613/682 : AGN central masses, broad-line region sizes (Peterson+, 2004)
J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)
J/ApJ/696/870 : Catalina Real-time Transient Survey (CRTS) (Drake+, 2009)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011)
J/ApJ/753/106 : QSO variability with SDSS and POSS imaging (MacLeod+, 2012)
J/A+A/558/A149 : VLTI/MIDI AGN Large Program observations (Burtscher+, 2013)
J/ApJ/782/45 : SEAMBHs. I. Mrk 142, Mrk 335 & IRAS F12397+3333 (Du+, 2014)
J/MNRAS/439/690 : Optical/γ-ray variability in blazars (Hovatta+, 2014)
J/ApJ/788/159 : 17 Seyfert 1 galaxies light curves (Koshida+, 2014)
J/ApJ/792/30 : NEOWISE magnitudes for near-Earth objects (Mainzer+, 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/ApJ/804/L15 : SDSS-DR7 broad-line QSOs (Sun+, 2015)
J/ApJ/801/127 : 3.6um, 4.5um, B & V light curves of NGC 6418 (Vazquez+, 2015)
J/ApJ/851/21 : SDSS RM project first year of observations (Grier+, 2017)
J/ApJ/836/186 : Continuum-band lags in SDSS QSOs from PS1 obs. (Jiang+, 2017)
J/ApJ/856/6 : SEAMBHs IX. 10 new Hβ light curves (Du+, 2018)
J/ApJ/862/123 : griz light curves of 15 DES quasars (Mudd+, 2018)
J/ApJ/886/42 : Reverberation mapping & opt. spectra data of AGNs (Du+, 2019)
J/A+A/632/A61 : NGC1068 CO and HCO images (Garcia-Burillo+, 2019)
J/ApJ/887/38 : SDSS RM Project: CIV lags & LCs from 4yrs obs. (Grier+, 2019)
J/ApJS/243/21 : Broad-line AGN from SDSS-DR7 (Liu+, 2019)
J/ApJ/886/33 : MIR RM analysis of 87 z<0.5 PG AGNs (Lyu+, 2019)
J/ApJ/886/150 : VRI and K-band light curves of type 1 AGNs (Minezaki+, 2019)
J/ApJ/901/55 : SDSS-RM project: MgII lags from 4yrs obs. (Homayouni+, 2020)
J/ApJS/249/17 : SDSS QSO DR14 spectral properties (Rakshit+, 2020)
J/AJ/159/259 : Opt-NIR LCs of the QSO 3C 273 (Sobrino Figaredo+, 2020)
J/ApJ/900/58 : Opt-IR LC compilation of DES Stripe 82 quasars (Yang+, 2020)
J/ApJS/253/20 : SEAMBHs XII. Reberberation mapping for 15 PG QSOs (Hu+, 2021)
J/ApJ/920/9 : YFOSC light curves of PG 0923+201 and PG 1001+291 (Li+, 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/ApJ/925/52 : LAMP 2016: velocity-resolved Hb lags in Seyfert (U+, 2022)
http://asas-sn.osu.edu/photometry : ASAS-SN photometry homepage
Byte-by-byte Description of file: table3a.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Object ID number
9- 20 F12.6 d MJD [51075.2/59550.5] Modified Julian Date
22- 28 F7.4 mJy Flux [-0.06/9.71] Flux
30- 35 F6.4 mJy e_Flux [0.0001/1.7] Uncertainty in Flux
37- 43 A7 --- Survey Name of the imaging survey ("ASAS-SN", "CRTS",
DES, PS1, PTF, SDSS or ZTF) and filter
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3b.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Object ID number
9- 20 F12.6 d MJD [55203.2/59213.5] Modified Julian Date
22- 28 F7.4 mJy Flux [0.08/38.6] Flux
30- 35 F6.4 mJy e_Flux [0.0048/0.3] Uncertainty in Flux
37- 42 A6 --- Survey Light curves ("W1_obs" or "W2_obs")
--------------------------------------------------------------------------------
Byte-by-byte Description of file:table3c.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Object ID number
9- 20 F12.6 d MJD [55203.2/59213.5] Modified Julian Date
22- 28 F7.4 mJy Flux [0.067/35.2] Flux
30- 35 F6.4 mJy e_Flux [0.004/0.51] Uncertainty in Flux
37- 42 A6 --- Survey Light curves ("W1_adc" or "W2_adc")
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 7 A7 --- ID Object ID number
9- 27 A19 --- SDSSo SDSS name (1)
29- 33 F5.3 --- z [0.02/3.34] Spectroscopic redshift
35- 39 F5.2 [10-7W] logLbol [43.4/47.64] Log of AGN bolometric
luminosity; erg/s
41- 44 F4.2 [10-7W] e_logLbol [0/0.15] Uncertainty in logLbol
46- 50 F5.2 --- logEdd [-2.8/0.51]? Log of Eddington ratio
obtained from this work
52- 55 F4.2 --- e_logEdd [0.14/1.4]? Uncertainty in logEdd
57- 60 F4.2 --- rmaxW1 [0.6/1]? Peak correlation coefficient
from ICCF between optical and W1-band
light curve
62- 68 F7.5 --- pvalW1 [0/0.2]? P(rmax)tau>0 value obtained
between optical and W1-band light curve
70- 73 I4 d tauW1 [28/4397]? Observed-frame W1-band time
lag from ICCF
75- 78 I4 d e_tauW1 [17/1170]? Lower 1-sigma uncertainty in
tauW1
80- 82 I3 d E_tauW1 [12/709]? Upper 1-sigma uncertainty in
tauW1
84- 87 I4 d tauW1ADC [29/4432]? Observed-frame W1-band time
lag corrected for AD contamination from
ICCF
89- 91 I3 d e_tauW1ADC [19/942]? Lower 1-sigma uncertainty in
tauW1ADC
93- 96 I4 d E_tauW1ADC [13/1102]? Upper 1-sigma uncertainty in
tauW1ADC
98- 101 I4 d tauW1ADCJAV [40/4337]? Observed-frame W1-band time
lag corrected for AD contamination from
JAVELIN
103- 105 I3 d e_tauW1ADCJAV [3/853]? Lower 1-sigma uncertainty in
tauW1ADCJAV
107- 109 I3 d E_tauW1ADCJAV [3/716]? Upper 1-sigma uncertainty in
tauW1ADCJAV
111- 114 F4.2 --- rmaxW2 [0.54/0.97]? Peak correlation
coefficient from ICCF between optical
and W2-band light curve
116- 121 F6.4 --- pvalW2 [0/0.33]? P(rmax)tau>0 value obtained
between optical and W2-band light curve
123- 126 I4 d tauW2 [34/4068]? Observed-frame W2-band time
lag from ICCF
128- 130 I3 d e_tauW2 [12/650]? Lower 1-sigma uncertainty in
tauW2
132- 134 I3 d E_tauW2 [14/923]? Upper 1-sigma uncertainty in
tauW2
136- 139 I4 d tauW2ADC [36/4134]? Observed-frame W2-band time
lag corrected for AD contamination from
ICCF
141- 143 I3 d e_tauW2ADC [12/679]? Lower 1-sigma uncertainty in
tauW2ADC
145- 147 I3 d E_tauW2ADC [15/924]? Upper 1-sigma uncertainty in
tauW2ADC
149- 152 I4 d tauW2ADCJAV [38/3681]? Observed-frame W2-band time
lag corrected for AD contamination from
JAVELIN
154- 157 I4 d e_tauW2ADCJAV [4/1058]? Lower 1-sigma uncertainty in
tauW2ADCJAV
159- 162 I4 d E_tauW2ADCJAV [3/1255]? Upper 1-sigma uncertainty in
tauW2ADCJAV
--------------------------------------------------------------------------------
Note (1): Position-based name but some zeros are sometimes missing;
see the SimbadName column in VizieR for the corrected name. Note added by CDS.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
Acknowledgements:
Jong-Hak Woo [jhwoo _ at _ snu.ac.kr] and Amit Kumar Mandal
for the coordinates of sample 1.
License: CC-BY-4.0
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Aug-2026