A. M. Mosquera

The structure of the broad-line region in active galactic nuclei. I. Reconstructed velocity-delay maps

We present velocity-resolved reverberation results for five active galactic nuclei. We recovered velocity-delay maps using the maximum entropy method for four objects: Mrk 335, Mrk 1501, 3C?120, and PG?2130+099. For the fifth, Mrk 6, we were only able to measure mean time delays in different velocity bins of the H? emission line. The four velocity-delay maps show unique dynamical signatures for each object. For 3C?120, the Balmer lines show kinematic signatures consistent with both an inclined disk and infalling gas, but the He II??4686 emission line is suggestive only of inflow. The Balmer lines in Mrk 335, Mrk 1501, and PG?2130+099 show signs of infalling gas, but the He II emission in Mrk 335 is consistent with an inclined disk. We also see tentative evidence of combined virial motion and infalling gas from the velocity-binned analysis of Mrk 6. The maps for 3C?120 and Mrk 335 are two of the most clearly defined velocity-delay maps to date. These maps constitute a large increase in the number of objects for which we have resolved velocity-delay maps and provide evidence supporting the reliability of reverberation-based black hole mass measurements.

The Structure of the X-Ray and Optical Emitting Regions of the Lensed Quasar Q 2237+0305

We use gravitational microlensing to determine the size of the X-ray and optical emission regions of the quadruple lens system Q 2237+0305. The optical half-light radius, log(R 1/2, V /cm) = 16.41 ? 0.18 (at ?rest = 2018??), is significantly larger than the observed soft, (1.1-3.5 keV in the rest frame), and hard, (3.5-21.5 keV in the rest frame), band X-ray emission. There is weak evidence that the hard component is more compact than the soft, with . This wavelength-dependent structure agrees with recent results found in other lens systems using microlensing techniques, and favors geometries in which the corona is concentrated near the inner edge of the accretion disk. While the available measurements are limited, the size of the X-ray emission region appears to be roughly proportional to the mass of the central black hole.

COSMOGRAIL: the COSmological MOnitoring of GRAvItational Lenses - XIII. Time delays and 9-yr optical monitoring of the lensed quasar RX J1131−1231

We present the results from nine years of optically monitoring the gravitationally lensed z(QSO) = 0.658 quasar RX J1131-1231. The R-band light curves of the four individual images of the quasar were obtained using deconvolution photometry for a total of 707 epochs. Several sharp quasar variability features strongly constrain the time delays between the quasar images. Using three different numerical techniques, we measured these delays for all possible pairs of quasar images while always processing the four light curves simultaneously. For all three methods, the delays between the three close images A, B, and C are compatible with being 0, while we measured the delay of image D to be 91 days, with a fractional uncertainty of 1.5% (1 sigma), including systematic errors. Our analysis of random and systematic errors accounts in a realistic way for the observed quasar variability, fluctuating microlensing magnification over a broad range of temporal scales, noise properties, and seasonal gaps. Finally, we find that our time-delay measurement methods yield compatible results when applied to subsets of the data.

The Microlensing Properties of a Sample of 87 Lensed Quasars

Gravitational microlensing is a powerful tool for probing the physical properties of quasar accretion disks and properties of the lens galaxy such as its dark matter fraction and mean stellar mass. Unfortunately, the number of lensed quasars (~90) exceeds our monitoring capabilities. Thus, estimating their microlensing properties is important for identifying good microlensing candidates as well as for the expectations of future surveys. In this work, we estimate the microlensing properties of a sample of 87 lensed quasars. While the median Einstein radius crossing timescale is 20.6 years, the median source crossing timescale is 7.3 months. Broadly speaking, this means that on ~10 year timescales roughly half the lenses will be quiescent, with the source in a broad demagnified valley, and roughly half will be active with the source lying in the caustic ridges. We also found that the location of the lens system relative to the cosmic microwave background dipole has a modest effect on microlensing timescales, and in theory microlensing could be used to confirm the kinematic origin of the dipole. As a corollary of our study we analyzed the accretion rate parameters in a sub-sample of 32 lensed quasars. At fixed black hole mass, it is possible to sample a broad range of luminosities (i.e., Eddington factors) if it becomes feasible to monitor fainter lenses.

Further Evidence That Quasar X-Ray Emitting Regions Are Compact: X-Ray And Optical Microlensing In The Lensed Quasar Q J0158-4325

We present four new seasons of optical monitoring data and six epochs of X-ray photometry for the doubly imaged lensed quasar Q J0158-4325. The high-amplitude, short-period microlensing variability for which this system is known has historically precluded a time delay measurement by conventional methods. We attempt to circumvent this limitation by the application of a Monte Carlo microlensing analysis technique, but we are only able to prove that the delay must have the expected sign (image A leads image B). Despite our failure to robustly measure the time delay, we successfully model the microlensing at optical and X-ray wavelengths to find a half-light radius for soft X-ray emission log(r(1/2), (X), (soft)/cm) = 14.3(-0.5)(+0.4), an upper limit on the half-light radius for hard X-ray emission log(r(1/2), (X), (hard)/cm) <= 14.6, and a refined estimate of the inclination-corrected scale radius of the optical R-band (rest frame 3100 angstrom) continuum emission region of log(r(s)/cm) = 15.6 +/- 0.3.

A REVERBERATION LAG FOR THE HIGH-IONIZATION COMPONENT OF THE BROAD-LINE REGION IN THE NARROW-LINE SEYFERT 1 Mrk 335

We present the first results from a detailed analysis of photometric and spectrophotometric data on the narrow-line Seyfert 1 (NLS1) galaxy Mrk 335, collected over a 120 day span in the fall of 2010. From these data we measure the lag in the He II {lambda}4686 broad emission line relative to the optical continuum to be 2.7 {+-} 0.6 days and the lag in the H{beta}{lambda}4861 broad emission line to be 13.9 {+-} 0.9 days. Combined with the line width, the He II lag yields a black hole mass M{sub BH} = (2.6 {+-} 0.8) Multiplication-Sign 10{sup 7} M{sub Sun }. This measurement is consistent with measurements made using the H{beta}{lambda}4861 line, suggesting that the He II emission originates in the same structure as H{beta}, but at a much smaller radius. This constitutes the first robust lag measurement for a high-ionization line in an NLS1 galaxy and supports a scenario in which the He II emission originates from gas in virial motion rather than outflow.

A Study of Gravitational Lens Chromaticity Using Ground-based Narrowband Photometry

We present observations of wavelength-dependent flux ratios for four gravitational lens systems (SDSS J1650+4251, HE 0435–1223, FBQ 0951+2635, and Q 0142–100) obtained with the Nordic Optical Telescope. The use of narrowband photometry, as well as the excellent seeing conditions during the observations, allows us to study their chromatic behavior. For SDSS J1650+4251, we determine the extinction curve of the dust in the zL = 0.58 lens galaxy and find that the 2175 A feature is absent. In the case of HE 0435–1223, we clearly detect chromatic microlensing. This allows us to estimate the wavelength-dependent size of the accretion disk. We find an R-band disk size of rR s = 13 ± 5 light days for a linear prior on rR s and rR s = 7 ± 6 light days for a logarithmic prior. For a power-law size-wavelength scaling of rs λ p , we were able to constrain the value of the exponent to p = 1.3 ± 0.3 for both rR s priors, which is in agreement with the temperature profiles of simple thin disk models (p = 4/3).

THE STRUCTURE OF THE ACCRETION DISK IN THE LENSED QUASAR SBS 0909+532

We derive the size and temperature profile of the accretion disk of the lensed quasar SBS 0909+532 by measuring the wavelength dependence (chromaticity) of the microlensing magnification produced by the stars in the lens galaxy. After correcting for extinction using the flux ratios of 14 emission lines, we observe a marked change in the B-A flux ratio with wavelength, varying from –0.67 ± 0.05 mag at (rest frame) ~1460 A to –0.24 ± 0.07 mag at ~6560 A. For λ 7000 A both effects, extinction and microlensing, look minimal. Simulations indicate that image B rather than A is strongly microlensed. If we model the change in disk size from 1460 A to 6560 A using a Gaussian source (I ∝ exp(–R 2/2r 2 s )) with a disk size scaling with wavelength as rs ∝ λ p , we find rs = 7+5 –3 light-days at 1460 A and p = 0.9+0.6 –0.3 for uniform priors on rs and p, and rs = 4+3 –3 light-days and p = 1.0+0.6 –0.4 for a logarithmic prior on rs . The disk temperature profile T ∝ R –1/p is consistent with thin disk theory (T ∝ R –3/4), given the uncertainties. The estimates of rs are also in agreement with the size inferred from thin disk theory using the estimated black hole mass (M BH 2 × 109 M ☉) but not with the smaller size estimated from thin disk theory and the optical flux. We also use the flux ratios of the unmicrolensed emission lines to determine the extinction curve of the dust in the lens galaxy, finding that it is similar to that of the LMC2 Supershell.

THE AVERAGE SIZE AND TEMPERATURE PROFILE OF QUASAR ACCRETION DISKS

We use multi-wavelength microlensing measurements of a sample of 10 image pairs from 8 lensed quasars to study the structure of their accretion disks. By using spectroscopy or narrowband photometry, we have been able to remove contamination from the weakly microlensed broad emission lines, extinction, and any uncertainties in the large-scale macro magnification of the lens model. We determine a maximum likelihood estimate for the exponent of the size versus wavelength scaling (rs ∝λ p , corresponding to a disk temperature profile of T∝r –1/p ) of and a Bayesian estimate of p = 0.8 ± 0.2, which are significantly smaller than the prediction of the thin disk theory (p = 4/3). We have also obtained a maximum likelihood estimate for the average quasar accretion disk size of lt-day at a rest frame wavelength of λ = 1026 A for microlenses with a mean mass of M = 1 M ☉, in agreement with previous results, and larger than expected from thin disk theory.

A Consistent Picture Emerges: A Compact X-ray Continuum Emission Region in the Gravitationally Lensed Quasar SDSS J0924+0219

We analyze the optical, UV, and X-ray microlensing variability of the lensed quasar SDSS J0924+ 0219 using six epochs of Chandra data in two energy bands (spanning 0.4-8.0 keV, or 1-20 keV in the quasar rest frame), 10 epochs of F275W (rest-frame 1089 angstrom) Hubble Space Telescope data, and high-cadence R-band (rest-frame 2770 angstrom) monitoring spanning 11 years. Our joint analysis provides robust constraints on the extent of the X-ray continuum emission region and the projected area of the accretion disk. The best-fit half-light radius of the soft X-ray continuum emission region is between 5 x 10(13) and 10(15) cm, and we find an upper limit of 10(15) cm for the hard X-rays. The best-fit soft-band size is about 13 times smaller than the optical size, and roughly 7GM(BH)/c(2) for a 2.8 x 10(8) M-circle dot black hole, similar to the results for other systems. We find that the UV emitting region falls in between the optical and X-ray emitting regions at 10(14) cm < r(1/2,UV) <3x10(15) cm. Finally, the optical size is significantly larger, by 1.5 sigma, than the theoretical thin-disk estimate based on the observed, magnification-corrected I-band flux, suggesting a shallower temperature profile than expected for a standard disk.