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Strong-lensing time delays enable the measurement of the Hubble constant ( H 0 ) independently of other traditional methods. The main limitation to the precision of time-delay cosmography is mass-sheet degeneracy (MSD). Some of the previous TDCOSMO analyses broke the MSD by making standard assumptions about the mass density profile of the lens galaxy, reaching 2% precision from seven lenses. However, this approach could potentially bias the H 0 measurement or underestimate the errors. For this work, we broke the MSD for the first time using spatially resolved kinematics of the lens galaxy in RXJ1131−1231 obtained from the Keck Cosmic Web Imager spectroscopy, in combination with previously published time delay and lens models derived from Hubble Space Telescope imaging. This approach allowed us to robustly estimate H 0 , effectively implementing a maximally flexible mass model. Following a blind analysis, we estimated the angular diameter distance to the lens galaxy D d  = 865 −81 +85 Mpc and the time-delay distance D Δt  = 2180 −271 +472 Mpc, giving H 0  = 77.1 −7.1 +7.3 km s −1 Mpc −1 – for a flat Λ cold dark matter cosmology. The error budget accounts for all uncertainties, including the MSD inherent to the lens mass profile and line-of-sight effects, and those related to the mass–anisotropy degeneracy and projection effects. Our new measurement is in excellent agreement with those obtained in the past using standard simply parametrized mass profiles for this single system ( H 0  = 78.3 −3.3 +3.4 km s −1 Mpc −1 ) and for seven lenses ( H 0  = 74.2 −1.6 +1.6 km s −1 Mpc −1 ), or for seven lenses using single-aperture kinematics and the same maximally flexible models used by us ( H 0  = 73.3 −5.8 +5.8 km s −1 Mpc −1 ). This agreement corroborates the methodology of time-delay cosmography. 

Fast empirical models of the broad emission line region (BLR) are a powerful tool to interpret velocity-resolved reverberation mapping (RM) data, estimate the mass of the supermassive black holes, and gain insight into its geometry and kinematics. Much of the effort so far has been devoted to describing the emissivity of one emission line at a time. We present here an alternative approach aimed at describing the underlying BLR gas distribution, by exploiting simple numerical recipes to connect it with emissivity. This approach is a step toward describing multiple emission lines originating from the same gas and allows us to clarify some issues related to the interpretation of RM data. We illustrate this approach—implemented in the codeCARAMEL-gas—using three data sets covering the Hβemission line (Mrk 50, Mrk 1511, Arp 151) that have been modeled using the emissivity-based version of the code. As expected, we find differences in the parameters describing the BLR gas and emissivity distribution, but the emissivity-weighted lag measurements and all other model parameters including black hole mass and overall BLR morphology and kinematics are consistent with the previous measurements. We also model the Hαemission line for Arp 151 using both the gas- and emissivity-based BLR models. We find ionization stratification in the BLR with Hαarising at larger radii than Hβ, while all other model parameters are consistent within the uncertainties.

 

We present a reanalysis of reverberation mapping data from 2005 for the Seyfert galaxy NGC 4151, supplemented with additional data from the literature to constrain the continuum variations over a significantly longer baseline than the original monitoring program. Modeling of the continuum light curve and the velocity-resolved variations across the Hβemission line constrains the geometry and kinematics of the broad line region (BLR). The BLR is well described by a very thick disk with similar opening angle (θ_o≈ 57°) and inclination angle (θ_i≈ 58°), suggesting that our sight line toward the innermost central engine skims just above the surface of the BLR. The inclination is consistent with constraints from geometric modeling of the narrow-line region, and the similarity between the inclination and opening angles is intriguing given previous studies of NGC 4151 that suggest BLR gas has been observed temporarily eclipsing the X-ray source. The BLR kinematics are dominated by eccentric bound orbits, with ∼10% of the orbits preferring near-circular motions. With the BLR geometry and kinematics constrained, the models provide an independent and direct black hole mass measurement of$\log M_{\mathrm{BH}}/M_{\odot }={7.22}_{-0.10}^{+0.11}$or$M_{\mathrm{BH}}={1.66}_{-0.34}^{+0.48}\times {10}^7$M_⊙, which is in good agreement with mass measurements from stellar dynamical modeling and gas dynamical modeling. NGC 4151 is one of the few nearby broad-lined Seyferts where the black hole mass may be measured via multiple independent techniques, and it provides an important test case for investigating potential systematics that could affect the black hole mass scales used in the local universe and for high-redshift quasars.

 

The broad-line region (BLR) size–luminosity relation has paramount importance for estimating the mass of black holes in active galactic nuclei (AGNs). Traditionally, the size of the HβBLR is often estimated from the optical continuum luminosity at 5100 Å, while the size of the HαBLR and its correlation with the luminosity is much less constrained. As a part of the Seoul National University AGN Monitoring Project, which provides 6 yr photometric and spectroscopic monitoring data, we present our measurements of the Hαlags of high-luminosity AGNs. Combined with the measurements for 42 AGNs from the literature, we derive the size–luminosity relations of the HαBLR against the broad Hαand 5100 Å continuum luminosities. We find the slope of the relations to be 0.61 ± 0.04 and 0.59 ± 0.04, respectively, which are consistent with the Hβsize–luminosity relation. Moreover, we find a linear relation between the 5100 Å continuum luminosity and the broad Hαluminosity across 7 orders of magnitude. Using these results, we propose a new virial mass estimator based on the Hαbroad emission line, finding that the previous mass estimates based on scaling relations in the literature are overestimated by up to 0.7 dex at masses lower than 10⁷M_⊙.

 

We combine our dynamical modeling black-hole mass measurements from the Lick AGN Monitoring Project 2016 sample with measured cross-correlation time lags and line widths to recover individual scale factors,f, used in traditional reverberation-mapping analyses. We extend our sample by including prior results from Code for AGN Reverberation and Modeling of Emission Lines (caramel) studies that have utilized our methods. Aiming to improve the precision of black-hole mass estimates, as well as uncover any regularities in the behavior of the broad-line region (BLR), we search for correlations betweenfand other AGN/BLR parameters. We find (i) evidence for a correlation between the virial coefficient${\log }_{10}(f_{\mathrm{mean},\sigma })$and black-hole mass, (ii) marginal evidence for a similar correlation between${\log }_{10}(f_{\mathrm{rms},\sigma })$and black-hole mass, (iii) marginal evidence for an anticorrelation of BLR disk thickness with${\log }_{10}(f_{\mathrm{mean},\mathrm{FWHM}})$and${\log }_{10}(f_{\mathrm{rms},\mathrm{FWHM}})$, and (iv) marginal evidence for an anticorrelation of inclination angle with${\log }_{10}(f_{\mathrm{mean},\mathrm{FWHM}})$,${\log }_{10}(f_{\mathrm{rms},\sigma })$, and${\log }_{10}(f_{\mathrm{mean},\sigma })$. Last, we find marginal evidence for a correlation between line-profile shape, when using the root-mean-square spectrum,${\log }_{10}{(\mathrm{FWHM}/\sigma )}_{\mathrm{rms}}$, and the virial coefficient,${\log }_{10}(f_{\mathrm{rms},\sigma })$, and investigate how BLR properties might be related to line-profile shape usingcaramelmodels.

 

ABSTRACT We report upon 3 years of follow-up and confirmation of doubly imaged quasar lenses through imaging campaigns from 2016 to 2018 with the Near-Infrared Camera2 (NIRC2) on the W. M. Keck Observatory. A sample of 57 quasar lens candidates are imaged in adaptive-optics-assisted or seeing-limited K′-band observations. Out of these 57 candidates, 15 are confirmed as lenses. We form a sample of 20 lenses adding in a number of previously known lenses that were imaged with NIRC2 in 2013–14 as part of a pilot study. By modelling these 20 lenses, we obtain K′-band relative photometry and astrometry of the quasar images and the lens galaxy. We also provide the lens properties and predicted time delays to aid planning of follow-up observations necessary for various astrophysical applications, e.g. spectroscopic follow-up to obtain the deflector redshifts for the newly confirmed systems. We compare the departure of the observed flux ratios from the smooth-model predictions between doubly and quadruply imaged quasar systems. We find that the departure is consistent between these two types of lenses if the modelling uncertainty is comparable. 

Abstract We present reverberation mapping measurements for the prominent ultraviolet broad emission lines of the active galactic nucleus Mrk 817 using 165 spectra obtained with the Cosmic Origins Spectrograph on the Hubble Space Telescope. Our ultraviolet observations are accompanied by X-ray, optical, and near-infrared observations as part of the AGN Space Telescope and Optical Reverberation Mapping Program 2 (AGN STORM 2). Using the cross-correlation lag analysis method, we find significant correlated variations in the continuum and emission-line light curves. We measure rest-frame delayed responses between the far-ultraviolet continuum at 1180 Å and Ly α λ 1215 Å ( 10.4 − 1.4 + 1.6 days), N v λ 1240 Å ( 15.5 − 4.8 + 1.0 days), Si iv + ]O iv λ 1397 Å ( 8.2 − 1.4 + 1.4 days), C iv λ 1549 Å ( 11.8 − 2.8 + 3.0 days), and He ii λ 1640 Å ( 9.0 − 1.9 + 4.5 days) using segments of the emission-line profile that are unaffected by absorption and blending, which results in sampling different velocity ranges for each line. However, we find that the emission-line responses to continuum variations are more complex than a simple smoothed, shifted, and scaled version of the continuum light curve. We also measure velocity-resolved lags for the Ly α and C iv emission lines. The lag profile in the blue wing of Ly α is consistent with virial motion, with longer lags dominating at lower velocities, and shorter lags at higher velocities. The C iv lag profile shows the signature of a thick rotating disk, with the shortest lags in the wings, local peaks at ±1500 km s −1 , and a local minimum at the line center. The other emission lines are dominated by broad absorption lines and blending with adjacent emission lines. These require detailed models, and will be presented in future work.