Technique of polarimetric observations of faint objects at the 6-m BTA telescope

Monthly Notices of the Royal Astronomical Society

Shapovalova

Borisov

2015

Self Cite

Here we present the spectropolarimetric observations of the radio loud active galaxy 3C 390.3 in the period 2009-2014 (24 epochs). The galaxy has been observed with the 6-meter telescope of SAO RAS using the SCORPIO spectropolarimeter. We explore the variability and lags in the polarized light of the continuum and broad Hα line. We give the Stokes parameters Q, U , degree of linear polarization P and the position angle of the polarization plane, ϕ, for 24 epochs.We find a small lag (10-40 days) between the unpolarized and polarized continuum that is significantly smaller than the estimated lags for the unpolarized broad emission lines (lag(Hα)∼138-186 and lag(Hβ)∼60-79 days). This shows that the region of the variable polarized continuum is significantly smaller than the broad line region, indicating that a part of the polarized continuum is coming from the jet. The lag of the polarized light in the Hα line (89-156 days) indicates an additional component to the disc one that has an outflowing velocity of ∼-1200 km s −1 . This region seems to depolarize the polarized broad Hα line emitted from the disc and scattered in the inner part of the torus.

Section: Observationmentioning

confidence: 81%

Spectropolarimetric monitoring of active galaxy 3C 390.3 with 6-m telescope SAO RAS in the period 2009–2014

Monthly Notices of the Royal Astronomical Society

Shapovalova

Borisov

2015

Self Cite

“…In each epoch a series of the images was shot to take into account the variation of the atmosphere. The method of polarimetric observations with SCORPIO is described in Afanasiev & Amirkhanyan (2012). We obtained Mrk 6 spectra from 12 epochs in the 2010-2013 monitoring period.…”

Section: Observational Testmentioning

confidence: 99%

Measuring the AGN Sublimation Radius with a New Approach: Reverberation Mapping of Broad Line Polarization

Shablovinskaya

2020

ApJ

Here we give an observational method for measurements of the equatorial scattering region radius using variability in the polarized broad lines in Type 1 active galactic nuclei (AGNs). The polarization in broad lines of Type 1 AGNs is mostly caused by equatorial scattering, where specific features allow one to separate its contribution from the total polarized flux. We propose to monitor variability in the polarized line flux and find the time lag between the nonpolarized continuum and polarized broad line variability. The distance to the scattering screen can then be determined from the time delay.The method was, for the first time, applied to the observations of the Type 1 AGN Mrk 6, and we found that the size of the scattering region in this AGN is around 100 light days. That is significantly smaller than the dusty region size estimated by the infrared interferometric observations and also larger than known broad line region (BLR) size. This indicates that the scattering region lies between the BLR and the dusty region and could be used as a probe of the dust sublimation radius.

“…In this polarimetric mode of the instrument, an achromatic half-wave phase plate and a Wollaston prism are installed before a prism. The Wollaston prism, separating the beam into the ordinary o and extraordinary e rays by 5 deg (2 on the celestial sphere), is inserted in the parallel beam (Afanasiev et al, 2012). We use the mask (high 2 and diameter 4), which cuts non-overlapping area.…”

Section: Single Wollaston Prismmentioning

confidence: 99%

CCD polarimetry of distant comets C/2010 S1 (LINEAR) and C/2010 R1 (LINEAR) at the 6-m telescope of the SAO RAS

Ivanova

Dlugach

Planetary and Space Science

et al. 2015

We present first measurements of the degree of linear polarization of distant comets C/2010 S1 (LINEAR) and C/2010 R1 (LINEAR) at heliocentric distances r = 5.9 -7.0 AU. Observations were carried out with the SCORPIO-2 focal reducer at the 6-m telescope of the Special Astrophysical Observatory (Russia). Both comets showed considerable level of activity (significant dust comae and tails) beyond a zone where water ice sublimation is negligible (up to 5 AU). Significant spatial variations both in the intensity and polarization are found in both comets. The slope of radial profiles of intensity changes gradually with the distance from the photocenter: from  0.7 near the nucleus up to about  1.3 for larger distances (up to 100000 km). The variation in polarization profiles indicates the non uniformity in the polarization distribution over the coma. The polarization degree over the coma gradually increases (in absolute value) with increasing the photocentric distance from of about 1.9% up to 3% for comet C/2010 S1 (LINEAR), and from of about 2.5% up to 3.5% for comet C/2010 R1 (LINEAR). These polarization values are significantly higher than typical value of the whole coma polarization ( −1.5%) for comets at heliocentric distances less than 5 AU. The obtained photometric and polarimetric data are compared with those derived early for other comets at smaller heliocentric distances. Numerical modeling of light scattering characteristics was performed for media composed of particles with different refractive index, shape, and size. The computations were made by using the superposition T-matrix method. We obtained that for comet C/2010 S1 (LINEAR), the dust in the form of aggregates of overall radius R ~ 1.3 μm composed of N = 1000 spherical monomers with radius a = 0.1 μm, refractive index m = 1.65 + i 0.05, allows to obtain a satisfactory agreement between the results of polarimetric observations of comet C/2010 S1 and computations.