V. T. Doroshenko

REVERBERATION MAPPING MEASUREMENTS OF BLACK HOLE MASSES IN SIX LOCAL SEYFERT GALAXIES

We present the final results from a high sampling rate, multi-month, spectrophotometric reverberation mapping campaign undertaken to obtain either new or improved Hβ reverberation lag measurements for several relatively low-luminosity active galactic nuclei (AGNs). We have reliably measured the time delay between variations in the continuum and Hβ emission line in six local Seyfert 1 galaxies. These measurements are used to calculate the mass of the supermassive black hole at the center of each of these AGNs. We place our results in context to the most current calibration of the broad-line region (BLR) RBLR–L relationship, where our results remove outliers and reduce the scatter at the low-luminosity end of this relationship. We also present velocity-resolved Hβ time-delay measurements for our complete sample, though the clearest velocity-resolved kinematic signatures have already been published.

Steps toward Determination of the Size and Structure of the Broad-Line Region in Active Galactic Nuclei. XVI. A 13 Year Study of Spectral Variability in NGC 5548

We present the final installment of an intensive 13 year study of variations of the optical continuum and broad Hemission line in the Seyfert 1 galaxy NGC 5548. The database consists of 1530 optical continuum measurements and 1248 Hmeasurements. The Hvariations follow the continuum variations closely, with a typical time delay of about 20 days. However, a year-by-year analysis shows that the magnitude of emission-line time delay is correlated with the mean continuum flux. We argue that the data are consistent with the simple model prediction between the size of the broad-line region and the ionizing luminosity, r / L 1=2 ion . Moreover, the apparently linear nature of the correlation between the Hresponse time and the nonstellar optical continuum Fopt arises as a consequence of the changing shape of the continuum as it varies, specifically Fopt / F 0:56 UV . Subject headings: galaxies: active — galaxies: individual (NGC 5548) — galaxies: nuclei — galaxies: Seyfert

Lag-Luminosity Relationship for Interband Lags between Variations in B, V, R, and I Bands in Active Galactic Nuclei

We determine interband lags between variations in the B band and variations in the V, R, and I bands for 14 active galactic nuclei observed at the Crimean Astrophysical Observatory. The computed lags range from tenths of a day to several days, and it is positive (that is, V, R, and I bands lag behind the B band) in most cases, except for a few cases for the V filter. In some cases, the lag is greater than zero, with more than 3 σ confidence. The lag is systematically less for the V filter than for the red filters, and the lag determined from the cross-correlation function (CCF) centroid is systematically greater than the lag determined from the CCF peak. We find that the lag scales with luminosity as Lb, where b ≈ 0.4-0.5. We attribute this lag to the light time travel effect, so it reflects the geometrical size of the region that emits optical continuum. We consider a model in which optical emission is mainly reprocessed emission that arises in the accretion disk heated by an X-ray source above the disk.

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.

A REVISED BROAD-LINE REGION RADIUS AND BLACK HOLE MASS FOR THE NARROW-LINE SEYFERT 1 NGC 4051

We present the first results from a high sampling rate, multimonth reverberation mapping campaign undertaken primarily at MDM Observatory with supporting observations from telescopes around the world. The primary goal of this campaign was to obtain either new or improved Hβ reverberation lag measurements for several relatively low luminosity active galactic nuclei (AGNs). We feature results for NGC 4051 here because, until now, this object has been a significant outlier from AGN scaling relationships, e.g., it was previously a ∼2–3σ outlier on the relationship between the broad-line region (BLR) radius and the optical continuum luminosity—the RBLR–L relationship. Our new measurements of the lag time between variations in the continuum and Hβ emission line made from spectroscopic monitoring of NGC 4051 lead to a measured BLR radius of RBLR = 1.87 +0.54 −0.50 light days and black hole mass of MBH = (1.73 +0.55 −0.52 ) × 10 6 M� . This radius is consistent with that expected from the RBLR–L relationship, based on the present luminosity of NGC 4051 and the most current calibration of the relation by Bentz et al.. We also present a preliminary look at velocity-resolved Hβ light curves and time delay measurements, although we are unable to reconstruct an unambiguous velocity-resolved reverberation signal.

DIVERSE KINEMATIC SIGNATURES FROM REVERBERATION MAPPING OF THE BROAD-LINE REGION IN AGNs

A detailed analysis of the data from a high sampling rate, multi-month reverberation mapping campaign, undertaken primarily at MDM Observatory with supporting observations from telescopes around the world, reveals that the Hbeta emission region within the broad line regions (BLRs) of several nearby AGNs exhibit a variety of kinematic behaviors. While the primary goal of this campaign was to obtain either new or improved Hbeta reverberation lag measurements for several relatively low luminosity AGNs (presented in a separate work), we were also able to unambiguously reconstruct velocity-resolved reverberation signals from a subset of our targets. Through high cadence spectroscopic monitoring of the optical continuum and broad Hbeta emission line variations observed in the nuclear regions of NGC 3227, NGC 3516, and NGC 5548, we clearly see evidence for outflowing, infalling, and virialized BLR gas motions, respectively.

The radio delay of the exceptional 3C 454.3 outburst. Follow-up WEBT observations in 2005-2006

Context. In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from the near-IR to the hard X-ray frequencies. A mm outburst peaked in June-July 2005, and it was followed by a flux increase at high radio frequencies. Aims. In this paper we report on multifrequency monitoring by the WEBT aimed at following the further evolution of the outburst in detail. In particular, we investigate the expected correlation and time delays between the optical and radio emissions in order to derive information on the variability mechanisms and jet structure. Methods. A comparison among the light curves at different frequencies is performed by means of visual inspection and discrete correlation function, and the results are interpreted with a simple model taking into account Doppler factor variations of geometric origin. Results. The high-frequency radio light curves show a huge outburst starting during the dimming phase of the optical one and lasting more than 1 year. The first phase is characterized by a slow flux increase, while in early 2006 a major flare is observed. The lower-frequency radio light curves show a progressively delayed and fainter event, which disappears below 8 GHz. We suggest that the radio major peak is not physically connected with the spring 2005 optical one, but it is actually correlated with a minor optical flare observed in October-November 2005. This interpretation | involves both an intrinsic and a geometric mechanism. The former is represented by disturbances travelling down the emitting jet, the latter being due to the curved-jet motion, with the consequent differential changes of viewing angles of the different emitting regions.

Intermediate resolution Hβ spectroscopy and photometric monitoring of 3C 390.3 I. Further evidence of a nuclear accretion disk

We have monitored the AGN 3C 390.3 between 1995 and 2000. A historical B-band light curve dating back to 1966 shows a large increase in brightness during 1970{1971, followed by a gradual decrease down to a minimum in 1982. During the 1995{2000 lapse the broad H emission and the continuum flux varied by a factor of 3. Two large amplitude outbursts, of dierent duration, in continuum and H light were observed i.e.: in October 1994 a brighter flare that lasted1000 days and in July 1997 another one that lasted700 days were detected. The response time lag of the emission lines relative to flux changes of the continuum has been found to vary with time i.e. during 1995{1997 a lag of about 100 days is evident, while during 1998{1999 a double valued lag of100 days and35 days is present in our data. The flux in the H wings and line core vary simultaneously, a behavior indicative of predominantly circular motions in the BLR. Important changes of the H emission proles were detected: at times, we found proles with prominent asymmetric wings, like those normaly seen in Sy1s, while at other times, we observe proles with weak, almost symmetrical wings, similar to those of Sy1.8s. We further dismiss the hypothesis that the double peaked H proles in this object originate in a massive binary BH. Instead, we found that the radial velocity dierence between the red and blue bumps is anticorrelated with the light curves of H and continuum radiation. This implies that the zone that contributes most of the energy to the emitted line changes in radius within the disk. The velocity dierence increases, corresponding to smaller radii, as the continuum flux decreases. When the continuum flux increases the hump velocity dierence decreases. These transient phenomena are expected to result from the variable accretion rate close to the central source. The optical continuum and the H flux variations might be related to changes in X-ray emission modulated by a variable accretion rate, changing the surface temperature of the disk, as a result of a variable X-ray irradiation (Ulrich 2000). Theoretical H proles were computed for an accretion disk, the observed proles are best reproduced by an inclined disk (25) whose region of maximum emission is located roughly at 200 Rg .T he mass of the black hole in 3C 390.3, estimated from the reverberation analysis is Mrev 2:1 10 9 M, 5 times larger than previous

Thirty years of continuum and emission-line variability in NGC 5548

We analyze a total of 827 optical spectra of NGC 5548 obtained over the 30 year period 1972-2001 for the purpose of studying the long-term behavior of the broad Hβ line profile. The variability characteristics, such as mean continuum and emission-line fluxes, rms variability amplitude, autocorrelation functions, and cross-correlation results, are found to be similar for CCD spectra obtained during the period 1989-2001 and for archival pre-CCD spectra from 1972 to 1988. The only significant difference between these two sets of data is that the mean Hβ flux is higher for 1972-1988. While the Hβ profile can vary dramatically on timescales of months to years, the mean profiles for these two periods are similar, but not identical. We searched for correlations among Hβ profile parameters (such as line width, line centroid, blue-to-red ratio of the line wing fluxes) and investigated their relationship to the continuum flux. Only trivial correlations were found, specifically the correlation between continuum and line fluxes and the anticorrelation between line width and line flux, the latter following from the former and from the inverse correlation between line time lag and line width expected for gravitationally dominated motion.

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.