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J/ApJ/836/186   Continuum-band lags in SDSS QSOs from PS1 obs.   (Jiang+, 2017)

Detection of time lags between quasar continuum emission bands based on Pan-STARRS light curves. Jiang Y.-F., Green P.J., Greene J.E., Morganson E., Shen Y., Pancoast A., Macleod C.L., Anderson S.F., Brandt W.N., Grier C.J., Rix H.-W., Ruan J.J., Protopapas P., Scott C., Burgett W.S., Hodapp K.W., Huber M.E., Kaiser N., Kudritzki R.P., Magnier E.A., Metcalfe N., Tonry J.T., Wainscoat R.J., Waters C. <Astrophys. J., 836, 186-186 (2017)> =2017ApJ...836..186J (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Photometry, ugriz ; Redshifts ; Surveys Keywords: accretion, accretion disks; galaxies: active; galaxies: nuclei; quasars: general Abstract: We study the time lags between the continuum emission of quasars at different wavelengths, based on more than four years of multi-band (g, r, i, z) light curves in the Pan-STARRS Medium Deep Fields. As photons from different bands emerge from different radial ranges in the accretion disk, the lags constrain the sizes of the accretion disks. We select 240 quasars with redshifts of z∼1 or z∼0.3 that are relatively emission-line free. The light curves are sampled from day to month timescales, which makes it possible to detect lags on the scale of the light crossing time of the accretion disks. With the code JAVELIN, we detect typical lags of several days in the rest frame between the g band and the riz bands. The detected lags are ∼2-3 times larger than the light crossing time estimated from the standard thin disk model, consistent with the recently measured lag in NGC 5548 and microlensing measurements of quasars. The lags in our sample are found to increase with increasing luminosity. Furthermore, the increase in lags going from g-r to g-i and then to g-z is slower than predicted in the thin disk model, particularly for high-luminosity quasars. The radial temperature profile in the disk must be different from what is assumed. We also find evidence that the lags decrease with increasing line ratios between ultraviolet Fe II lines and Mg II, which may point to changes in the accretion disk structure at higher metallicity. Description: We have chosen to study quasars in the Medium Deep Fields of the Pan-STARRS1 (PS1) survey. The PS1 survey used a wide-field f/4.4 optical telescope system designed for survey mode operation at the Haleakala Observatory on the island of Maui in Hawaii. The PS1 photometric system is described in Tonry+ (2012, J/ApJ/750/99), and passband shapes are detailed in Stubbs+ (2010ApJS..191..376S). File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 107 240 Sample summary table3.dat 51 39 Rest frame lags for the subsample cLD (quasars with significant detections; see section 4.1)
See also: V/147 : The SDSS Photometric Catalogue, Release 12 (Alam+, 2015) VII/279 : SDSS quasar catalog: twelfth data release (Paris+, 2017) J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004) J/ApJ/622/129 : Lag-luminosity relationship in AGN (Sergeev+, 2005) J/ApJ/633/638 : Variable quasar sample from SDSS (Wilhite+, 2005) J/ApJ/698/895 : Variations in QSOs optical flux (Kelly+, 2009) J/ApJS/194/45 : QSO properties from SDSS-DR7 (Shen+, 2011) J/A+A/536/A84 : X-ray variability of AGN (Vagnetti+, 2011) J/A+A/542/A83 : CAIXA. II. AGNs from excess variance analysis (Ponti+, 2012) J/ApJ/750/99 : The Pan-STARRS1 photometric system (Tonry+, 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/806/129 : Space telescope RM project. II. Swift data (Edelson+, 2015) J/ApJS/216/4 : SDSS-RM project: technical overview (Shen+, 2015) J/ApJ/821/56 : Space telescope RM project. III. (Fausnaugh+, 2016) J/ApJ/818/30 : Lag measurements for z<0.8 QSOs from the SDSS-RM (Shen+, 2016) Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 19 A19 --- SDSS SDSS identifier 21- 28 F8.4 deg RAdeg Right Ascension in decimal degrees (J2000) 30- 36 F7.4 deg DEdeg Declination in decimal degrees (J2000) 38- 41 F4.2 --- z [0.1/1.1] Spectroscopic redshift 43- 47 F5.2 mag gmag [15.6/24.1] Pan-STARRS1 apparent g band magnitude 49- 52 F4.2 mag e_gmag [0/0.5] Uncertainty in gmag 54- 58 F5.2 mag rmag [15.4/22.2] Pan-STARRS1 apparent r band magnitude 60- 63 F4.2 mag e_rmag [0/0.2] Uncertainty in rmag 65- 69 F5.2 mag imag [15.4/22.1] Pan-STARRS1 apparent i band magnitude 71- 74 F4.2 mag e_imag [0/0.2] Uncertainty in imag 76- 80 F5.2 mag zmag [15.2/23.4] Pan-STARRS1 apparent z band magnitude 82- 85 F4.2 mag e_zmag [0.01/0.8] Uncertainty in zmag 87- 91 F5.2 [10-7W] logL [0/47] Log luminosity; erg/s 93- 97 F5.2 [solMass] logMBH [0/10] Log blackhole mass 99-107 A9 --- sigma2 Normalized g band excess variance
Byte-by-byte Description of file: table3.dat
Bytes Format Units Label Explanations
1- 19 A19 --- SDSS SDSS identifier ( 21- 25 F5.2 d dt(g-r) [-1.5/5.6] Rest frame lag Δtg-r 27- 30 F4.2 d e_dt(g-r) [0.2/5.3] dt(g-r) uncertainty 32- 35 F4.2 d dt(g-i) [0.8/9.3] Rest frame lag Δtg-i 37- 40 F4.2 d e_dt(g-i) [0.2/6.3] dt(g-i) uncertainty 42- 46 F5.2 d dt(g-z) [1.7/14.4] Rest frame lag Δtg-z 48- 51 F4.2 d e_dt(g-z) [0.2/3.8] dt(g-z) uncertainty
History: From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 06-Oct-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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