J/ApJ/964/167 Swift and LCO LCs of PG 1302-102 (Liu+, 2024)
Intensive Swift and LCO monitoring of PG 1302-102: active galactic nucleus disk
reverberation mapping of a supermassive black hole binary candidate.
Liu T., Edelson R., Hernandez Santisteban J.V., Kara E., Montano J.,
Gelbord J., Horne K., Barth A.J., Cackett E.M., Kaplan D.L.
<Astrophys. J., 964, 167 (2024)>
=2024ApJ...964..167L 2024ApJ...964..167L
ADC_Keywords: Active gal. nuclei; QSOs; Photometry, ultraviolet;
Photometry, UBV; Photometry, ugriz
Keywords: Active galactic nuclei ; Supermassive black holes ;
Reverberation mapping
Abstract:
We present an intensive multiwavelength monitoring campaign of the
quasar PG 1302-102 with Swift and the Las Cumbres Observatory network
telescopes. At z∼0.3, it tests the limits of the reverberation mapping
(RM) technique in probing the accretion disk around a supermassive
black hole (SMBH) and extends the parameter space to high masses and
high accretion rates. This is also the first time the RM technique has
been applied to test disk structures predicted in the SMBH binary
model that has been suggested for this source. PG 1302-102 was
observed at a ∼daily cadence for ∼9 months in 14 bands spanning from
X-ray to UV and optical wavelengths, and it shows moderate to
significant levels of variability correlated between wavelengths. We
measure the interband time lags, which are consistent with a
τ∝λ4/3 relation as expected from standard disk
reprocessing, albeit with large uncertainties. The disk size implied
by the lag spectrum is consistent with the expected disk size for its
black hole mass within uncertainties. While the source resembles other
reverberation-mapped active galactic nuclei in many respects, and we
do not find evidence supporting the prevalent hypothesis that it hosts
an SMBH binary, we demonstrate the feasibility of studying SMBH
binaries from this novel angle and suggest possibilities for the LSST
Deep Drilling Fields.
Description:
The Neil Gehrels Swift Observatory observed PG 1302 from 2021-Dec-03
to 2022-Aug-25 at a ∼half-day cadence for the first ∼100 days and a
∼daily cadence for the remainder of the campaign (Swift Cycle 17;
proposal number 1720044; PI: T. Liu). The X-ray Telescope (XRT)
observations were carried out in photon counting mode, and
Ultraviolet/Optical Telescope (UVOT) observations were made in
six-filter image mode in the W2, M2, W1, U, B, V filters.
See Section 2.1.
The Swift observations were coordinated with intensive ground-based
monitoring with the Las Cumbres Observatory Global Telescope (LCO)
network in seven optical bands: SDSS ugri, Pan-STARRS z, and Johnson
B, V. LCO observed PG 1302 from 2021 February 11 to 2021 August 20,
2021 December 13 to 2022 August 26, and again from 2022 December 2 to
2023 August 16 at a ∼daily to few-day cadence, and a total of 12 1m
robotic telescopes participated in the campaign (as part of the LCO
Key Project 2020B-006; PI: J. V. Hernandez Santisteban).
See Section 2.2.
Additionally, the 0.5m robotic telescope at the Dan Zowada Memorial
Observatory also observed the source from 2021-Feb-09 to 2022-Jun-06
in griz bands for ∼40 epochs in each band. However, due to their
larger measurement uncertainties, the Zowada data are not used in the
cross-correlation analysis.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
----------------------------------------------------------
13 05 33.01 -10 33 19.4 PG 1302-102 = QSO B1302-1017
----------------------------------------------------------
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 25 1307 Swift UV and optical light curves
table3.dat 23 1780 Inter-calibrated LCO light curves
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See also:
II/207 : Palomar-Green catalog UV-excess stellar objects (Green+ 1986)
III/157 : An Ultraviolet Atlas of Quasar and Blazar Spectra (Kinney+, 1991)
VIII/85 : SPECFIND V2.0 Catalog of radio continuum spectra (Vollmer+ 2009)
VIII/104 : SPECFIND V3.0 Catalog of radio continuum spectra (Stein+, 2021)
I/358 : Gaia DR3 Part 4. Variability (Gaia Collaboration, 2022)
I/361 : Gaia Focused Product Release (Gaia FPR) (Gaia Collaboration, 2023)
J/ApJ/676/262 : PKS1302-102 intergalactic absorption system (Cooksey+, 2008)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/MNRAS/438/3058 : 15GHz variability of γ-ray blazars (Richards+, 2014)
J/MNRAS/453/1562 : CRTS close supermassive black hole binaries (Graham+, 2015)
J/ApJ/806/129 : Space telescope RM project. II. Swift data (Edelson+, 2015)
J/AJ/152/25 : The UV-bright Quasar Survey (UVQS) DR1 (Monroe+, 2016)
J/ApJ/821/56 : Space telescope RM project. III. LCs (Fausnaugh+, 2016)
J/ApJ/840/41 : X-ray/UV Swift monitoring of NGC 4151 (Edelson+, 2017)
J/ApJS/233/17 : Swift/BAT AGN sp. survey. V. X-ray data (Ricci+, 2017)
J/ApJ/870/123 : Swift optical & UV flux of four AGNs (Edelson+, 2019)
J/ApJ/896/1 : SEAMBHs. XI. Mrk 142 X-ray to optical LCs (Cackett+, 2020)
J/ApJS/261/2 : BASS. XXII. Swift/BAT AGN Sp. Survey DR2 cat. (Koss+, 2022)
J/ApJ/947/62 : griz light curves of Mrk 335 (Kara+, 2023)
Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 A2 --- Band Swift/UVOT filter identifier
4- 12 F9.3 d MJD [59551/59816.1] Modified Julian Date
14- 19 F6.3 10-17W/m2/nm Flux [3.16/21.02] Observed flux in Band;
10-15erg/s/cm2/Å
21- 25 F5.3 10-17W/m2/nm e_Flux [0.08/0.8] Uncertainty in Flux
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 1 A1 --- Band [BVugriz] LCO filter identifier
3- 11 F9.3 d MJD [59256.3/60172.5] Modified Julian Date
13- 17 F5.3 mJy Flux [2.53/5.34] Observed flux in Band
19- 23 F5.3 mJy e_Flux [0.009/0.2] Uncertainty in Flux
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History:
From electronic version of the journal
License: CC-BY-4.0
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 08-Jul-2026