arXiv subjects

L. C. Popović

Publications and source records attributed to L. C. Popović.

3 recordsLinked to original sources

arXiv2021

Polarization in broad emission lines of Active Galactic Nuclei

We discuss the polarization of broad emission lines in the type 1 active galactic nuclei (AGNs). The polarization depends on the geometry of the broad line region (BLR), and also on the polarization mechanism, or distribution of the scattering material. Therefore the polarization measurements can indicate the geometry of the BLR and the mechanism of polarization (equatorial or polar scattering). In addition, the polarization angle (PA) shape across the line profile can be used to measure the supermassive black hole (SMBH) mass, and constrain the BLR characteristics. We give an overview of ours and other recent investigations of the polarization in broad lines from both aspects: theoretical and observational.

astro-ph.GA↗

arXiv2018

Active Galaxy Science in the LSST Deep-Drilling Fields: Footprints, Cadence Requirements, and Total-Depth Requirements

This white paper specifies the footprints, cadence requirements, and total-depth requirements needed to allow the most-successful AGN studies in the four currently selected LSST Deep-Drilling Fields (DDFs): ELAIS-S1, XMM-LSS, CDF-S, and COSMOS. The information provided on cadence and total-depth requirements will also likely be applicable to enabling effective AGN science in any additional DDFs that are chosen.

astro-ph.IM↗

arXiv2017

Long-term optical spectral monitoring of NGC 7469

We present the results of the long-term (20-year period, from 1996 to 2015) optical spectral monitoring of the Seyfert 1 galaxy NGC 7469. The variation in the light-curves of the broad He II λ4686A Hβ and Hα lines, and the continuum at 5100A and 6300A have been explored. The maximum of activity was in 1998, and the variability in the continuum and lines seems to have two periods of around 1200 and 2600 days, however these periodicities should be taken with caution because of the red-noise. Beside these periods, there are several short-term (1-5 days) flare-like events in the light-curves. There are good correlations between the continuum fluxes and Hα and Hβ line fluxes, but significantly smaller correlation between the He II and continuum. We found that the time-lags between the continuum and broad lines are different for Hβ (~20 l.d.) and Hα (~3 l.d.), and that He II also has a smaller lag (~2-3 l.d.). The Hα and Hβ line profiles show a slight red asymmetry, and the broad line profiles did not changed in the 20-year period. Using the lags and widths of Hα and Hβ we estimated the central black hole mass and found that it is ~(1-6)x$10^7 M_{\odot}$, which is in agreement with previous reverberation estimates.

astro-ph.GA↗