Polarimetric Reverberation Mapping in Medium-Band Filters

TL;DR

This paper introduces a new medium-band filter approach for polarimetric reverberation mapping of active galactic nuclei, enabling more efficient and accessible observations of their central structures.

Contribution

It adapts the polarimetric reverberation mapping method to medium-band filters, reducing telescope time and resource requirements compared to spectropolarimetric techniques.

Findings

Successful initial monitoring of AGNs Mrk 335, Mrk 509, and Mrk 817.

Progress in implementing the medium-band filter method.

Discussion of future observational campaigns and potential improvements.

Abstract

Earlier, we suggested the "reload" concept of the polarimetric reverberation mapping of active galactic nuclei (AGN), proposed for the first time more than 10 years ago. We have successfully tested this approach of reverberation mapping of the broad emission line on the galaxy Mrk 6. It was shown that such an idea allows one to look at the AGN central parsec structure literally in a new light. However, the method originally assumed the use of spectropolarimetric observations, expensive in terms of telescope time, and implemented on rare large telescopes. Currently, we propose an adaptation of the polarimetric reverberation mapping of broad lines in medium-band filters following the idea of the photometric reverberation mapping, when filters are selected so that their bandwidth is oriented to the broad line and the surrounding continuum near. In this paper, we present the progress status of such monitoring conducted jointly at the Special astrophysical observatory and Asiago Cima Ekar observatory (OAPd/INAF) with support from Rozhen National Astronomical Observatory (NAO), some first results for the most frequently observed AGNs Mrk 335, Mrk 509, and Mrk 817, and the discussion of the future perspectives of the campaign.