FRADO explains the Low Ionized Broad Emission Lines of AGNs

Broad emission lines (BELs) are the most characteristic features in the spectra of active galaxies. They mostly show either a single-peaked or double-peaked profiles; and originate from a complex dynamics of the likely discrete clouds moving in a spatially extended region so-called Broad Line Region (BLR). We follow a non-hydrodynamical single-cloud approach to the BLR dynamics based on the dust-driving model of Czerny & Hryniewicz. We previously showed in details that the 2.5D version of the model could provide us with the 3D geometry of the BLR. In this paper, we provide a large grid of results based on which we aim at testing the model with calculation of the spectral line generic profiles. We show that the shape of profiles not only depends on the accretion rate of the source, the black hole mass, and the viewing angle, but also it is most significantly affected by the adopted dust-to-gas mass ratio regulating the strength of the radiation pressure. We also show that the model can nicely/consistently explain the low ionized broad lines of the mean spectrum of quasars, such as MgII and Hbeta.Comment: 9 pages, 5 figures, Submitted to A&

The Wind Dynamics of Super-Eddington Sources in FRADO

We perform non-hydrodynamical 2.5D simulations to study the dynamics of material above accretion disk based on the disk radiation pressure acting on dust. We assume a super-accreting underlying disk with the accretion rate of 10 times the Eddington rate with central black hole mass ranging from $10^7$ up to $10^9 M_{\odot}$. Such high accretion rates are characteristic for extreme sources. We show that for high accretors radiatively dust-driving mechanism based on FRADO model always leads to a massive outflow from the disk surface, and the failed wind develops only at larger radii. The outflow rate strongly depends on the black hole mass, and in optically-thick energy-driven solution can exceed the accretion rate for masses larger than $10^ 8 M_{\odot}$ but momentum-driven outflow does not exceed the accretion rate even for super-Eddington accretion, therefore not violating the adopted stationarity of the disk. However, even in this case the outflow from the disk implies a strong mechanical feedback.Comment: 13 pages, 3 figures, Accepted for publication in the journal of Dynamics (MDPI

Dusty plasma in active galactic nuclei

Since many years we know that dust in the form of the dusty-molecular torus is responsible for the obscuration in active galactic nuclei (AGN) at large viewing angles and thus for the classification of AGN. Recently, we gained some observational and theoretical insight into geometry of the region and the role of the dust in the dynamics of the outflow and failed winds. We will briefly touch on all these aspects, including our dust-based model (FRADO - Failed Radiatively Accelerated Dusty Outflow) of the formation of the Balmer lines in AGN.Comment: Partially based on talk at 31st Symposium on the Physics of Ionized Gases in Belgrade, submitted to the European Physical Journal D Topical Issue: "Physics of Ionized Gases and Spectroscopy of Isolated Complex Systems: Fundamentals and Applications

Time-delay measurement of MgII broad line response for the highly-accreting quasar HE 0413-4031: Implications for the MgII-based radius-luminosity relation

We present the monitoring of the AGN continuum and MgII broad line emission for the quasar HE 0413-4031 ($z=1.38$) based on the six-year monitoring by the South African Large Telescope (SALT). We managed to estimate a time-delay of $302.6^{+28.7}_{-33.1}$ days in the rest frame of the source using seven different methods: interpolated cross-correlation function (ICCF), discrete correlation function (DCF), $z$-transformed DCF, JAVELIN, two estimators of data regularity (Von Neumann, Bartels), and $\chi^2$ method. This time-delay is below the value expected from the standard radius-luminosity relation. However, based on the monochromatic luminosity of the source and the SED modelling, we interpret this departure as the shortening of the time-delay due to the higher accretion rate of the source, with the inferred Eddington ratio of $\sim 0.4$. The MgII line luminosity of HE 0413-4031 responds to the continuum variability as $L_{\rm line}\propto L_{\rm cont}^{0.43\pm 0.10}$, which is consistent with the light-travel distance of the location of MgII emission at $R_{\rm out} \sim 10^{18}\,{\rm cm}$. Using the data of 10 other quasars, we confirm the radius-luminosity relation for broad MgII line, which was previously determined for broad H$\beta$ line for lower-redshift sources. In addition, we detect a general departure of higher-accreting quasars from this relation in analogy to H$\beta$ sample. After the accretion-rate correction of the light-travel distance, the MgII-based radius-luminosity relation has a small scatter of only $0.10$ dex.Comment: 39 pages (23 pages - Main text, 16 pages - Appendix), 21 figures, 14 tables; accepted for publication in the Astrophysical Journa

Time delay measurement of Mg II line in CTS C30.10 with SALT

We report 6 yr monitoring of a distant bright quasar CTS C30.10 (z = 0.90052) with the Southern African Large Telescope (SALT). We measured the rest-frame time-lag of $562\pm 2$ days between the continuum variations and the response of the Mg II emission line, using the Javelin approach. More conservative approach, based on five different methods, imply the time delay of $564^{+109}_{-71}$ days. This time delay, combined with other available measurements of Mg II line delay, mostly for lower redshift sources, shows that the Mg II line reverberation implies a radius-luminosity relation very similar to the one based on a more frequently studied H$\beta$ line.Comment: submitted to ApJ; comments welcom

Nonthermal Emission from Fall-back Clouds in the Broad-line Region of Active Galactic Nuclei

International audienceThe spectra of active galactic nuclei exhibit broad-emission lines that presumably originate in the broad-line region (BLR) with gaseous-dusty clouds in a predominantly Keplerian motion around the central black hole. Signatures of both inflow and outflow motion are frequently seen. The dynamical character of BLR is consistent with the scenario that has been branded as the failed radiatively accelerated dusty outflow. In this scheme, frequent high-velocity impacts of BLR clouds falling back onto the underlying accretion disk are predicted. The impact velocities depend mainly on the black hole mass, accretion rate, and metallicity, and they range from a few km s$^{−1}$ up to thousands of km s$^{−1}$. Formation of strong shocks due to the collisions can give rise to the production of relativistic particles and associated radiation signatures. In this work, the nonthermal radiation generated in this process is investigated, and the spectral energy distributions for different parameter sets are presented. We find that the nonthermal processes caused by the impacts of clouds can lead to emission in the X-ray and the gamma-ray bands, playing the cloud density and metallicity key roles