We present the results of long-term photometric monitoring of two active galactic nuclei, 2MASX J08535955+7700543 (z ∼ 0.106) and VII Zw 244 (z ∼ 0.131), being investigated by the reverberation mapping method in medium-band filters. To estimate the size of the broad line region, we have analyzed the light curves with the JAVELIN code. The emission line widths have been measured using the spectroscopic data obtained at the 6-m BTA telescope of SAO RAS. We give our estimates of the supermassive black hole masses lg(M/M ), 7.398 +0.153 −0.171 , and 7.049 +0.068 −0.075 , respectively.

Due to the first results on astrophysical X-ray polarization provided by IXPE observatory, the interest in wavelength-dependent synchrotron polarization of BL Lac type objects increases. This paper presents the results of multi-band optical observations of the well-known blazar named BL Lac (z = 0.069) in polarized light. It was shown that the object’s emission, regardless of its phase of activity, is characterized by the intraday variability of brightness and polarization with changes occurring on a time-scale of up to 1.5 hours without any stable oscillation period. Polarimetric observations in the different optical bands show that the degree and angle of polarization of the blazar depend on the wavelength, and the maximum chromatism, as well as the maximum observed polarization degree, was detected during the minimum brightness state; during the flare state, the polarization chromatism changed along with the flux gradient on the time-scale of an hour. Qualitatively, such behaviour can be described by the shock-in-jet model, yet the chromatism amplitude and its rapid changes differ significantly from the model predictions and challenge the numerical calculations.

No abstract

The improvement of the calibration relation for determining the size of the broad-line region from the observed optical luminosity of active galactic nuclei (AGN) is a necessary task to study fundamental parameters of distant AGNs such as mass of the central supermassive black hole. The most popular method of the BLR size estimation is the reverberation mapping based on measuring the time delay between the continuum flux and the flux in the emission lines. In our work, we apply the method of photometric reverberation mapping in medium-band filters, adapted for observations at the Zeiss-1000 telescope of the SAO RAS, for the study of AGN with broad lines in the range of redshifts 0.1 < z < 0.8. This paper describes the technique of observations and data processing, provides a sample of objects and demonstrates the stability of the used method. As a preliminary result for 2MASX J08535955+7700543 at z = 0.1 we have obtained time delay estimates of τ (ICCF ) = 32.2 ±10.6 days and τ (JAVELIN) = 39.5 +23.0 −15.8 days that are consistent with each other and also within the accuracy of the existing calibration relations.

This paper is devoted to the memory of Dr. Victor Afanasiev and his immense legacy. The report highlights the capabilities of two new instruments tested at the 1-meter Zeiss-1000 telescope of SAO RAS: the Stokes Polarimeter (StoP) and the MAGIC focal reducer. Optimized for the study of active galactic nuclei (AGN), methodically, these instruments are suitable for a wide range of small telescope tasks. The fields of view of StoP and MAGIC are 6' and 13' for direct images, respectively. The StoP device allows one to conduct photometric observations and polarimetric ones with a double Wollaston prism; the spectral mode was added to MAGIC. For a starlike target up to 14 mag in medium-band filters with a seeing of 1' ' for 20 minutes of total exposure, the photometry accuracy is better than 0.01 mag and the polarization accuracy is better than 0.6%. The available spectral range obtained with the volume phase holographic grating in MAGIC is 4000-7200AA with a dispersion of 2A/px. StoP and MAGIC received the first light in 2020 and are used in test mode at the Zeiss-1000. The report discusses the first results obtained by the authors with new instruments, as well as further prospects.