J/ApJ/806/129 Space telescope RM project. II. Swift data (Edelson+, 2015)
Space telescope and optical reverberation mapping project.
II. Swift and HST reverberation mapping of the accretion disk of NGC 5548.
Edelson R., Gelbord J.M., Horne K., McHardy I.M., Peterson B.M.,
Arevalo P., Breeveld A.A., De Rosa G., Evans P.A., Goad M.R., Kriss G.A.,
Brandt W.N., Gehrels N., Grupe D., Kennea J.A., Kochanek C.S., Nousek J.A.,
Papadakis I., Siegel M., Starkey D., Uttley P., Vaughan S., Young S.,
Barth A.J., Bentz M.C., Brewer B.J., Crenshaw D.M., Dalla Bonta E.,
De Lorenzo-Caceres A., Denney K.D., Dietrich M., Ely J., Fausnaugh M.M.,
Grier C.J., Hall P.B., Kaastra J., Kelly B.C., Korista K.T., Lira P.,
Mathur S., Netzer H., Pancoast A., Pei L., Pogge R.W., Schimoia J.S.,
Treu T., Vestergaard M., Villforth C., Yan H., Zu Y.
<Astrophys. J., 806, 129 (2015)>
=2015ApJ...806..129E 2015ApJ...806..129E (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Photometry, UBV ; Ultraviolet ; X-ray sources
Keywords: galaxies: active; galaxies: individual: NGC 5548;
galaxies: nuclei; galaxies: Seyfert
Abstract:
Recent intensive Swift monitoring of the Seyfert 1 galaxy NGC 5548
yielded 282 usable epochs over 125 days across six UV/optical bands
and the X-rays. This is the densest extended active galactic nucleus
(AGN) UV/optical continuum sampling ever obtained, with a mean
sampling rate <0.5 day. Approximately daily Hubble Space Telescope UV
sampling was also obtained. The UV/optical light curves show strong
correlations (rmax=0.57-0.90) and the clearest measurement to date
of interband lags. These lags are well-fit by a
τ∝λ4/3 wavelength dependence, with a normalization
that indicates an unexpectedly large disk radius of ∼0.35±0.05lt-day
at 1367Å, assuming a simple face-on model. The U band shows a
marginally larger lag than expected from the fit and surrounding
bands, which could be due to Balmer continuum emission from the
broad-line region as suggested by Korista and Goad. The UV/X-ray
correlation is weaker (rmax<0.45) and less consistent over time.
This indicates that while Swift is beginning to measure UV/optical
lags in general agreement with accretion disk theory (although the
derived size is larger than predicted), the relationship with X-ray
variability is less well understood. Combining this accretion disk
size estimate with those from quasar microlensing studies suggests
that AGN disk sizes scale approximately linearly with central black
hole mass over a wide range of masses.
Description:
In 2014 February-June, Swift executed a monitoring campaign on NGC5548
that was ground-breaking in two respects: 1) it was comprised of 360
separate visits over a ∼4 month period, of which 282 successful visits
were obtained, for a sampling rate (after removing bad data) better
than one visit every ∼0.5day, and 2) it utilized all six UVOT filters
in each visit, with 239 (84%) providing usable measurements in all six
filters.
The Swift XRT data were gathered in photon counting mode (see table 3).
In addition, a parallel HST emission-line reverberation mapping (RM)
campaign yielded daily UV spectroscopic monitoring of NGC 5548 over a
slightly longer period (see Paper I, De Rosa+, 2015, J/ApJ/806/128).
Objects:
---------------------------------------------------
RA (ICRS) DE Designation(s)
---------------------------------------------------
14 17 59.51 +25 08 12.5 NGC 5548 = LEDA 51074
---------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table2.dat 28 2606 Swift/UVOT data
table3.dat 35 725 Swift/XRT data
--------------------------------------------------------------------------------
See also:
J/ApJ/806/128 : Space telescope RM project. I. NGC5548 (De Rosa+, 2015)
J/ApJ/798/95 : HE1104-1805 BVRIJ light curves (Blackburne+, 2015)
J/ApJ/779/109 : Long-term monitoring of NGC 5548 (Peterson+, 2013)
J/MNRAS/433/1709 : PKS 0558-504 UVOT and XRT monitoring (Gliozzi+, 2013)
J/ApJ/753/104 : AGN identifications from AKARI and Swift (Matsuta+, 2012)
J/MNRAS/397/1177 : Swift-XRT observations of GRBs (Evans+, 2009)
J/ApJ/622/129 : Lag-luminosity relationship in AGN (Sergeev+, 2005)
J/ApJ/613/682 : AGN central masses & broad-line reg. sizes (Peterson+, 2004)
Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 d HJD Heliocentric Julian Date (1)
13- 16 A4 --- Filt Swift/UVOT filter used (UBV, UVM2, UVW1,
or UVW2) (1)
18- 22 F5.3 10-14cW/m2/nm Flux [0.5/4.4] Measured flux;
in 1e-14erg/s/cm2/Å unit
24- 28 F5.3 10-14cW/m2/nm e_Flux [0.01/0.2] Measured 1σ error in Flux
--------------------------------------------------------------------------------
Note (1): Note that this table includes all usable Swift observations of
NGC 5548, not just those from the intensive monitoring period.
The data are sorted first by filter, then by HJD.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 F11.3 D HJD Heliocentric Julian Date (1)
13- 17 F5.3 ct/s HX [0.1/2.2] Measured Swift 0.8-10keV X-ray count
rate
19- 23 F5.3 ct/s e_HX [0.01/0.3] Measured 1σ error in HX
25- 29 F5.3 ct/s SX [0.006/0.5] Measured Swift 0.3-0.8keV
X-ray count rate
31- 35 F5.3 ct/s e_SX [0.003/0.2] Measured 1σ error in SX
--------------------------------------------------------------------------------
Note (1): Note that this table includes all usable Swift observations of
NGC 5548, not just those from the intensive monitoring period,
sorted by HJD.
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
De Rosa et al. Paper I. 2015ApJ...806..128D 2015ApJ...806..128D Cat. J/ApJ/806/128
Edelson et al. Paper II. 2015ApJ...806..129E 2015ApJ...806..129E This Catalog
Fausnaugh et al. Paper III. 2016ApJ...821...56F 2016ApJ...821...56F Cat. J/ApJ/821/56
Goad et al. Paper IV. 2016ApJ...824...11G 2016ApJ...824...11G
Pei et al. Paper V. 2017ApJ...837..131P 2017ApJ...837..131P Cat. J/ApJ/837/131
Starkey et al. Paper VI. 2017ApJ...835...65S 2017ApJ...835...65S
Mathur et al. Paper VII. 2017ApJ...846...55M 2017ApJ...846...55M
Kriss et al. Paper VIII. 2019ApJ...881..153K 2019ApJ...881..153K Cat. J/ApJ/881/153
Dehghanian et al. Paper X. 2019ApJ...877..119D 2019ApJ...877..119D
Dehghanian et al. Paper XI. 2020ApJ...898..141D 2020ApJ...898..141D
Williams et al. Paper XII. 2020ApJ...902...74W 2020ApJ...902...74W
Dehghanian et al. Paper XIII. 2021ApJ...906...14D 2021ApJ...906...14D
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 16-Oct-2015