Long-Term Monitoring of the Broad-Line Region Properties in a Selected Sample of AGN

Abstract

We present the results of the long-term optical monitoring campaign of active galactic nuclei (AGN) coordinated by the Special Astrophysical Observatory of the Russian Academy of Science. This campaign has produced a remarkable set of optical spectra, since we have monitored for several decades different types of broad-line (type 1) AGN, from a Seyfert 1, double-peaked line, radio loud and radio quiet AGN, to a supermassive binary black hole candidate. Our analysis of the properties of the broad line region (BLR) of these objects is based on the variability of the broad emission lines. We hereby give a comparative review of the variability properties of the broad emission lines and the BLR of seven different type 1 AGNs, emphasizing some important results, such as the variability rate, the BLR geometry, and the presence of the intrinsic Baldwin effect. We are discussing the difference and similarity in the continuum and emission line variability, focusing on what is the impact of our results to the supermassive black hole mass determination from the BLR properties.

Oscillatory patterns in the light curves of five long-term monitored type 1 active galactic nuclei

“…The correlation of oscillatory patterns in the continuum and emission lines of all objects (except Arp 102B), can be a consequence of a more general correlation trend between the continuum and emission lines fluxes of these objects (see discussion for correlation between continuum and Hβ emission lines of these objects in Ilić et al 2017). In addition, as time coverage of observations of NGC 4151 continuum is shorter then time coverage of observations of the Hα line, our study did not investigate how the weak (or even absent in some time periods) correlation between the continuum and emission line fluxes of this object (see details in Shapovalova et al 2008) would affect the detection of correlation of their oscillatory patterns.…”

“…One can think that small variations in the light curves of E1821+643 (e.g. for the Hβ line Fvar ∼ 7%, see Ilić et al 2017), can be a reason that oscillatory patterns are not distorted. Based on the above discussion, NGC 5548 and E1821+643 represent dynamical extremes, the most chaotic and stable in our sample, respectively.…”

Variability and the Size–Luminosity Relation of the Intermediate-mass AGN in NGC 4395

“…Note that recent reverberation studies showed that more luminous AGNs are scattered below the best-fit relation given by Bentz et al (2013); see §4.3 for more details. NGC 4395 Bentz et al 2013Du et al 2016Grier et al 2017Ilić et al 2017Park et al 2017Rakshit et al 2019 Figure 10. BLR radius vs. 5100Å AGN luminosity.…”

“…Best-fit relation by Bentz et al (2013, Clean+ExtCorr in Table 14) is shown as a black solid line, with the shaded region indicating the 1σ confidence interval of the fit and the dotted lines representing the 1σ prediction interval of AGNs considering intrinsic scatter. AGNs shown here are from Bentz et al (2013), as well as Du et al (2016Du et al ( , 2018, Grier et al (2017), Ilić et al (2017), Park et al (2017), and Rakshit et al (2019). NGC 4395 is shown as a blue circle with black error bar.…”

“…Given the measured luminosity and size of the BLR, the offset of NGC 4395 from the size-luminosity relation is not significantly large when compared to more re-cent reverberation-mapping results. For example, AGNs from the studies by Du et al (2016Du et al ( , 2018, Grier et al (2017), and Ilić et al (2017) exhibit large scatter, and some of them are more offset than NGC 4395. Note that the AGNs in Du et al (2016Du et al ( , 2018 have a high accretion rate (e.g., super-Eddington), which may be the reason for the offset from the relation.…”