J/ApJ/880/126 SDSS RM project: continuum lags (Homayouni+, 2019)
The Sloan Digital Sky Survey Reverberation Mapping project: accretion disk sizes
from continuum lags.
Homayouni Y., Trump J.R., Grier C.J., Shen Y., Starkey D.A., Brandt W.N.,
Fonseca Alvarez G., Hall P.B., Horne K., Kinemuchi K., Li J.I.-H.,
McGreer I.D., Sun M., Ho L.C., Schneider D.P.
<Astrophys. J., 880, 126 (2019)>
=2019ApJ...880..126H 2019ApJ...880..126H
ADC_Keywords: QSOs; Redshifts; Surveys; Optical
Keywords: accretion, accretion disks ; galaxies: active ; galaxies: nuclei ;
quasars: general
Abstract:
We present accretion disk structure measurements from continuum lags
in the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM)
project. Lags are measured using the JAVELIN software from the
first-year SDSS-RM g and i photometry, resulting in well-defined lags
for 95 quasars, 33 of which have lag S/N>2σ. We also estimate
lags using the ICCF software and find consistent results, though with
larger uncertainties. Accretion disk structure is fit using a Markov
chain Monte Carlo approach, parameterizing the measured continuum lags
as a function of disk size normalization, wavelength, black hole mass,
and luminosity. In contrast with previous observations, our best-fit
disk sizes and color profiles are consistent (within 1.5σ) with
the Shakura & Sunyaev (1973A&A....24..337S 1973A&A....24..337S) analytic solution. We also
find that more massive quasars have larger accretion disks, similarly
consistent with the analytic accretion disk model. The data are
inconclusive on a correlation between disk size and continuum
luminosity, with results that are consistent with both no correlation
and the Shakura & Sunyaev expectation. The continuum lag fits have a
large excess dispersion, indicating that our measured lag errors are
underestimated and/or our best-fit model may be missing the effects of
orientation, spin, and/or radiative efficiency. We demonstrate that
fitting disk parameters using only the highest-S/N lag measurements
biases best-fit disk sizes to be larger than the disk sizes recovered
using a Bayesian approach on the full sample of well-defined lags.
Description:
The Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) project
is a pioneering multi-object RM campaign (Shen+ 2015, J/ApJS/216/4)
that has been simultaneously monitoring a sample of 849 quasars in a
single 7deg2 field since 2014. See Section 2.1.
We use the Baryon Oscillation Spectroscopic Survey spectrograph (BOSS)
covering wavelengths of 3650-10400Å with a spectral resolution of
R∼2000 with the spectrograph mounted on the 2.5m SDSS telescope. Our
study uses the first year of SDSS-RM spectroscopic observations,
obtained during seven dark/gray observing windows in 2014 January-July.
See Section 2.2.
The SDSS-RM program is supported by ground-based photometry from
multiple facilities, including the 3.6m Canada-France-Hawaii Telescope
(CFHT) and the 2.5m Steward Observatory Bok telescope.
See Section 2.3.
The combined monitoring from the SDSS, Bok, and CFHT telescopes
provides a total of 88 epochs of g-band photometry and 78 epochs of
i-band photometry.
This work is complementary to that of D. A. Starkey et al. (2019, in
preparation), which uses a different methodology to similarly measure
continuum lags from SDSS-RM quasars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 91 95 "Well-defined" quasar sample information
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See also:
VII/286 : SDSS quasar catalog, fourteenth data release (Paris+, 2018)
J/ApJ/622/129 : Lag-luminosity relationship in AGN (Sergeev+, 2005)
J/ApJS/166/470 : SDSS-Spitzer type I QSOs IR photometry (Richards+, 2006)
J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009)
J/ApJ/733/60 : Accretion rate of AGNs from COSMOS surveys (Trump+, 2011)
J/ApJ/788/48 : X-ray through NIR photometry of NGC 2617 (Shappee+, 2014)
J/ApJ/806/22 : SEAMBHs IV. Hβ time lags (Du+, 2015)
J/ApJ/806/129 : Space telescope RM project. II. Swift data (Edelson+, 2015)
J/ApJ/805/122 : X-ray properties of PHL1811 analogs and WLQs (Luo+, 2015)
J/ApJ/811/91 : SDSS-RM project: z<1 QSO host galaxies (Matsuoka+, 2015)
J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015)
J/ApJ/821/56 : Space telescope RM project III. NGC5548 LCs (Fausnaugh+, 2016)
J/ApJ/824/130 : SDSS/BOSS/TDSS CIV BAL quasars (Grier+, 2016)
J/ApJ/831/7 : SDSS-RM project: peak velocities of QSOs (Shen+, 2016)
J/ApJ/818/30 : Lag measurements for 15 z<0.8 QSOs from SDSS-RM (Shen+, 2016)
J/ApJ/840/41 : X-ray/UV Swift monitoring of NGC 4151 (Edelson+, 2017)
J/ApJ/840/97 : Optical RM campaign of 5 AGNs (Fausnaugh+, 2017)
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/ApJS/228/9 : Physical param. of ∼300000 SDSS-DR12 QSOs (Kozlowski, 2017)
J/ApJ/854/107 : Light curves of 2 Seyfert 1 galaxies (Fausnaugh+, 2018)
J/ApJ/862/123 : griz light curves of 15 DES quasars (Mudd+, 2018)
J/ApJ/870/123 : Swift optical & UV flux of four AGNs (Edelson+, 2019)
J/ApJS/249/17 : SDSS QSO DR14 spectral properties (Rakshit+, 2020)
J/ApJS/250/10 : SDSS-RM AGNs CFHT & Bok photom. over 4yrs (Kinemuchi+, 2020)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- RMID [16/840] Object identifier
5- 12 F8.4 deg RAdeg [211.28/216.1] Right Ascension (J2000)
14- 20 F7.4 deg DEdeg [51.67/54.6] Declination (J2000)
22- 26 F5.3 --- z [0.116/1.128] Object Redshift
28- 31 F4.2 [Msun] logMBH [6.6/9.4] log of black hole mass
using RM method
32 A1 --- f_logMBH [*] Flag on logMBH (1)
34- 37 F4.2 [Msun] e_logMBH [0.16/0.4] Lower uncertainty in logMBH
39- 42 F4.2 [Msun] E_logMBH [0.16/0.6] Upper uncertainty in logMBH
44- 48 F5.2 [10-7W] logL3000 [42.8/45.8] Monochromatic luminosity
at 3000 angstroms, in erg/s
50- 55 F6.2 d tau-ICCF [-98.4/96] Observed frame lag
obtained from ICCF (2)
57- 61 F5.2 d e_tau-ICCF [0.29/21] Lower uncertainty in tau-ICCF
63- 67 F5.2 d E_tau-ICCF [0.94/28] Upper uncertainty in tau-ICCF
69- 73 F5.2 d tau-JAV [-7.5/13.2] Observed frame lag
obtained using JAVELIN (3)
75- 79 F5.2 d e_tau-JAV [0.26/16] Lower uncertainty in tau-JAV
81- 85 F5.2 d E_tau-JAV [0.19/13] Upper uncertainty in tau-JAV
87- 91 F5.2 --- SNRtJAV [-4.2/13] Lag signal-to-noise (4)
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Note (1):
* = Mass is obtained using single epoch measurement.
These uncertainties are set to 0.4 dex.
Note (2): Our first RM analysis methodology is the interpolated
cross-correlation function (ICCF; Gaskell & Sparke 1986ApJ...305..175G 1986ApJ...305..175G
Gaskell & Peterson 1987ApJS...65....1G 1987ApJS...65....1G ; White & Peterson 1994PASP..106..879W 1994PASP..106..879W
and Peterson 2004IAUS..222...15P 2004IAUS..222...15P). See Section 3.1.
Note (3): We also compute lags using the JAVELIN software
(Zu+ 2011ApJ...735...80Z 2011ApJ...735...80Z). JAVELIN assumes a DRW model to predict the
light curves at unmeasured times. See Section 3.2.
Note (4): SNR is calculated accounting for the JAVELIN lag sign, if
the JAVELIN lag is positive the SNR is positive, if the JAVELIN lag is
negative the SNR is negative.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 19-Jan-2021