Variability in spectropolarimetric properties of Sy 1.5 galaxy Mrk 6

Abstract

Here we present an analysis of spectro-polarimetric observations of type 1.5\nAGN Mrk 6, performed with 6m telescope SAO RAN in 12 epochs (2010 -- 2013).\nAdditionally, the inter-stellar mater (ISM) polarization has been observed and\nits contribution to the AGN spectral polarization is taken into account.\n We measured Stokes parameters and determined the polarization parameters in\n12 spectra with and without correction for the ISM polarization. We estimated\nthe time lag between the unpolarized and polarized continuum flux variation of\nabout ~2 days, that indicates a compact scattering region which contributes to\nthe polarized continuum variability. The polarization in H{\\alpha} is complex,\nshowing three prominent components in the BLR, one redshifted around +3000 km/s\nthat corresponds to the red shoulder in H{\\alpha}, and two blue-shifted around\n-2000 km/s and -6000 km/s.\n We found that the ISM polarization has a very significant influence on the\nmeasured AGN polarization parameters. After correcting the observations for the\nISM polarization we were able to detect the Keplerian motion in the BLR.\n We give a new method for the black hole mass estimation using\nspectro-polarimetric observation in the line profile, finding the black hole\nmass in Mrk 6 of $M_{BH} \\sim 1.53 \\cdot 10^8 M_{\\odot}$, that is in a good\nagreement with reverberation estimates.\n