J/ApJ/827/118 A new reverberation mapping campaign on NGC 5548 (Lu+, 2016) ================================================================================ Reverberation mapping of the broad-line region in NGC 5548: evidence for radiation pressure? Lu K.-X., Du P., Hu C., Li Y.-R., Zhang Z.-X., Wang K., Huang Y.-K., Bi S.-L., Bai J.-M., Ho L.C., Wang J.-M. =2016ApJ...827..118L (SIMBAD/NED BibCode) ================================================================================ ADC_Keywords: Active gal. nuclei ; Spectroscopy ; Velocity dispersion ; Photometry Keywords: galaxies: active; galaxies: individual: NGC 5548; galaxies: nuclei Abstract: NGC 5548 is the best-observed reverberation-mapped active galactic nucleus with long-term, intensive monitoring. Here we report results from a new observational campaign between 2015 January and July. We measure the centroid time lag of the broad H{beta} emission line with respect to the 5100{AA} continuum and obtain {tau}_cent_=7.20_-0.35_^+1.33^days in the rest frame. This yields a black hole mass of M.=8.71_-2.61_^+3.21^x10^7^M_{sun}_ using a broad H{beta} line dispersion of 3124+/-302km/s and a virial factor of f_BLR_=6.3+/-1.5 for the broad-line region (BLR), consistent with the mass measurements from previous H{beta} campaigns. The high-quality data allow us to construct a velocity-binned delay map for the broad H{beta} line, which shows a symmetric response pattern around the line center, a plausible kinematic signature of virialized motion of the BLR. Combining all the available measurements of H{beta} time lags and the associated mean 5100{AA} luminosities over 18 campaigns between 1989 and 2015, we find that the H{beta} BLR size varies with the mean optical luminosity, but, interestingly, with a possible delay of 2.35_-1.25_^+3.47^ years. This delay coincides with the typical BLR dynamical timescale of NGC 5548, indicating that the BLR undergoes dynamical changes, possibly driven by radiation pressure. Description: The spectroscopic and photometric observations of NGC 5548 were made using the Yunnan Faint Object Spectrograph and Camera (YFOSC), mounted on the Lijiang 2.4m telescope at Yunnan Observatory, Chinese Academy of Sciences. Our observations started on 2015 January 7, and ended on 2015 July 11. We used Grism 14, which provides a resolution of 92{AA}/mm (1.8{AA}/pixel) and covers the wavelength range 3800-7200{AA}. To verify the calibration of the spectroscopic data, we also made photometric observations using a Johnson V filter. We took three consecutive exposures of 90s each. In total, we obtained 62 spectroscopic observations and 61 photometric observations, spanning a time period of 180 days. Objects: ------------------------------------------------- RA (ICRS) DE Designation(s) ------------------------------------------------- 14 17 59.51 +25 08 12.5 NGC 5548 = UGC 9149 ------------------------------------------------- File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file table1.dat 45 62 Continuum and H{beta} fluxes for NGC 5548 table4.dat 138 18 All the RM measurements of NGC 5548 -------------------------------------------------------------------------------- See also: J/ApJS/225/29 : NGC 5548 43 year-long monitoring in H{beta} (Bon+, 2016) J/ApJ/825/126 : SEAMBHs. V. The third year (Du+, 2016) J/ApJ/821/56 : Space telescope RM project III. NGC 5548 LC (Fausnaugh+, 2016) J/ApJ/806/129 : Space telescope RM project II. Swift data (Edelson+, 2015) J/ApJ/806/128 : Space telescope RM project I. NGC5548 (De Rosa+, 2015) J/ApJ/806/22 : SEAMBHs IV. H{beta} time lags (Du+, 2015) J/ApJ/782/45 : SEAMBHs. I. Mrk 142, Mrk 335, and IRAS F12397+3333 (Du+, 2014) J/ApJ/779/109 : Long-term monitoring of NGC 5548 (Peterson+, 2013) J/ApJ/702/1353 : H{beta} and V-band light curves of NGC 4051 (Denney+, 2009) J/ApJ/613/682 : AGN central masses & broad-line region sizes (Peterson+, 2004) J/A+A/422/925 : Profile variability in lines of NGC 5548 (Shapovalova+ 2004) J/A+A/371/79 : NGC 5548 UBVRI phot. & Halpha, Hbeta fluxes (Dietrich+, 2001) J/ApJ/510/659 : Size and Structure of AGN in NGC 5548 (Peterson+, 1999) J/A+A/314/43 : NGC 5548 Profile variability (Kollatschny+ 1996) Byte-by-byte Description of file: table1.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 7 F7.2 d JD1 Spectroscopic (F5100, H{beta}) observation date; JD-2450000 9- 12 F4.2 10-17W/m2/nm F5100 [2.7/6.5] 5100A continuum spectroscopic flux; 10^-15erg/s/cm^2^/Angstrom 14- 17 F4.2 10-17W/m2/nm e_F5100 [0.2/0.5] Uncertainty in F5100 19- 22 F4.2 10-16W/m2 FHb [5.6/8.7] H{beta} spectroscopic flux; 10^-13erg/s/cm^2^ 24- 27 F4.2 10-16W/m2 e_FHb [0.2/0.4] Uncertainty in FHb 29- 35 F7.2 d JD2 ? Photometric (V-band) observation date; JD-2450000 37- 40 F4.2 mag Vmag [1.3/1.7]? Johnson V-band; instrumental magnitude, arbitrary zeropoint 42- 45 F4.2 mag e_Vmag [0.01/0.08]? Uncertainty in Vmag -------------------------------------------------------------------------------- Byte-by-byte Description of file: table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 4 A4 --- --- [Year] 6- 7 I2 --- Yr Data set year number 9- 16 A8 "Y/M" Date1 UT date of starting observations 17 A1 --- --- [-] 18- 25 A8 "Y/M" Date2 UT date of ending observations 27- 33 F7.2 yr T Observation time in decimal years 35- 39 F5.3 --- Fvar [0.1/0.5]? Variability amplitude (1) 41- 45 F5.2 [10-7W] logL5100 [42.5/43.6] Log of 5100{AA} luminosity 47- 50 F4.2 [10-7W] e_logL5100 [0.08/0.2] logL5100 uncertainty 52- 56 F5.2 [10-7W] logLHb [41/42]? Log of H{beta} luminosity 58- 61 F4.2 [10-7W] e_logLHb [0.03/0.1]? logLHb uncertainty 63- 67 F5.2 d Hblag [4/27] H{beta} lag 69- 72 F4.2 d e_Hblag [0.3/7.3] Negative uncertainty on Hblag 74- 77 F4.2 d E_Hblag [0.6/6] Positive uncertainty on Hblag 79- 83 I5 km/s FWHM [4674/12771]? Full width half maximum of H{beta} line from mean spectra 85- 87 I3 km/s e_FWHM [36/574]? FWHM uncertainty 89- 92 I4 km/s Sig [1934/4266]? Dispersion velocity of H{beta} line from mean spectra 94- 96 I3 km/s e_Sig [5/642]? Sig uncertainty 98-102 I5 km/s FWHM2 [4044/11177]? Full width half maximum of H{beta} line from rms spectra 104-107 I4 km/s e_FWHM2 [112/2266]? FWHM2 uncertainty 109-112 I4 km/s Sig2 [1687/4270]? Dispersion velocity of H{beta} line from rms spectra 114-116 I3 km/s e_Sig2 [30/768]? Sig2 uncertainty 118-121 F4.2 [Msun] logM [7.4/8.2]? BH mass (logM_{dot}_) (2) 123-126 F4.2 [Msun] e_logM [0.1/0.3]? Negative uncertainty on logM 128-131 F4.2 [Msun] E_logM [0.1/0.4]? Positive uncertainty on logM 133-137 A5 --- Ref Reference(s) (3) 138 A1 --- f_Ref Flag on Ref (4) -------------------------------------------------------------------------------- Note (1): Following standard practice (e.g., Rodriguez-Pascual+ 1997ApJS..110....9R), we calculate the variability amplitude of the light curves of the 5100{AA} continuum and H{beta} emission line using Equation (1): F_var_=({sigma}^2^-{Delta}^2^)^0.5^/ where =N^-1^{Sigma}_i=1_^N^F_i_ is the average flux, F_i_ is the flux of the ith observation of the light curve, N is the total number of observations, {sigma}^2^={Sigma}_i=1_^N^(F_i_-)^2^/(N-1), {Delta}^2^={Sigma}_i=1_^N^{Delta}_i_^2^/N, and {Delta}_i_ is the uncertainty of F_i_. See section 3.1 for further explanations. Note (2): M_{dot}_ is calculated from the line dispersion of the rms spectrum with a virial factor of f_BLR_=6.3+/-1.5 (Ho & Kim 2014ApJ...789...17H). These campaigns yield a mean BH mass of =8.39+/-0.72x10^7^M_{sun}_. Note (3): References as follows: 1 = Kilerci Eser et al. (2015ApJ...801....8K), 2 = Collin et al. (2006A&A...456...75C), 3 = Peterson et al. (2004, J/ApJ/613/682), 4 = Bentz et al. (2007ApJ...662..205B), 5 = Denney et al. (2010ApJ...721..715D), 6 = Bentz et al. (2010ApJ...720L..46B), 7 = Fausnaugh et al. (2016, J/ApJ/821/56), 8 = This work. Note (4): Flag as follows: a = "Year 12" is compiled from the 12th RM observation in the AGN Watch project (Peterson+ 2002ApJ...581..197P). The cross-correlation analysis is very ambiguous (see Figure 2 of Peterson+ 2002ApJ...581..197P), and we excluded this data set in our analysis. b = Pancoast+ (2014MNRAS.445.3073P) modeled the data and provided the model-dependent H{beta} lag of 3.22_-0.54_^+0.66^days, which is consistent (within the uncertainties) with 4.17_-1.33_^+0.90^days determined by the cross correlation analysis in Bentz+ (2010ApJ...720L..46B). We use the H{beta} lag of Bentz+ (2010ApJ...720L..46B) for consistency. -------------------------------------------------------------------------------- History: From electronic version of the journal ================================================================================ (End) Prepared by [AAS], Emmanuelle Perret [CDS] 28-Nov-2016