Polarimetric Reverberation Mapping in Medium-Band Filters

Shablovinskaya, Elena; Уклеин, Р. И.; Malygin, Eugene; Ilić, D.; Ciroi, S.; Oparin, D. V.; Crepaldi, Luca; Slavcheva-Mihova, L.; Mihov, B.; Nikolov, Y.

doi:10.3390/universe9010052

Cited by 3 publications

(1 citation statement)

References 65 publications

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“…Polarized emission lines are typically due to scattering by material through the abovementioned external mechanisms, where the number and location of the scattering regions determine the observed polarization properties. If equatorial scattering is the dominant mechanism, a couple of characteristic polarization signatures would be observed-mainly a dip in the polarization degree and an S-shaped PA swing along the emission line profiles (Shablovinskaya et al 2023). Of the two, we do see a dip in the percentage of polarization at each emission line core region, but there is no evidence for any swing of the PA across the line (Figure 3).…”

Section: Discussionmentioning

confidence: 81%

Optical Spectropolarimetric Variability Properties in Blazars PKS 0637–75 and PKS 1510–089

Podjed,

Hickox,

Isler

et al. 2024

ApJ

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Spectropolarimetry is a powerful tool to investigate the central regions of active galactic nuclei (AGNs) as polarization signatures are key to probing magnetic field structure, evolution, and the physics of particle acceleration in jets. Optical linear polarization of blazars is typically greater than a few percent, indicating the emission is dominated by nonthermal synchrotron radiation, while polarization less than a few percent is common for other type 1 AGNs. We present a spectropolarimetric study of PKS 0637–75 and PKS 1510–089 to determine how the head-on orientation of a jet and dominant emission processes influence polarimetric variations in the broad lines and continuum. Observations were obtained biweekly from the Robert Stobie Spectrograph on the Southern African Large Telescope. Variability in the continuum polarization is detected for both PKS 0637–75 and PKS 1510–089, with a total average level of 2.5% ± 0.1% and 7.5% ± 0.1%, respectively. There is no clear polarization in the broad Balmer emission lines and weak polarization in Mg ii as the average level across all observations is 0.2% ± 0.1% for Hβ, 0.2% ± 0.3% for Hγ, and 0.6% ± 0.2% for Mg ii. We find that polarization measurements confirm the conclusions drawn from spectral energy distribution modeling of the disk–jet contributions to the emission as optical polarization and time variability for PKS 0637–75 are shown to be dominated by accretion disk emission while those of PKS 1510–089 are due to both disk and jet emission, with greater jet contribution during flaring states.

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Section: Discussionmentioning

confidence: 81%

Optical Spectropolarimetric Variability Properties in Blazars PKS 0637–75 and PKS 1510–089

Podjed,

Hickox,

Isler

et al. 2024

ApJ

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The size-luminosity relation of local active galactic nuclei from interferometric observations of the broad-line region

Amorim,

Bourdarot,

Brandner

et al. 2024

A&A

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By using the GRAVITY instrument with the near-infrared (NIR) Very Large Telescope Interferometer (VLTI), the structure of the broad (emission-)line region (BLR) in active galactic nuclei (AGNs) can be spatially resolved, allowing the central black hole (BH) mass to be determined. This work reports new NIR VLTI/GRAVITY interferometric spectra for four type 1 AGNs (Mrk 509, PDS 456, Mrk 1239, and IC 4329A) with resolved broad-line emission. Dynamical modelling of interferometric data constrains the BLR radius and central BH mass measurements for our targets and reveals outflow-dominated BLRs for Mrk 509 and PDS 456. We present an updated radius-luminosity (R-L) relation independent of that derived with reverberation mapping (RM) measurements using all the GRAVITY-observed AGNs. We find our R-L relation to be largely consistent with that derived from RM measurements except at high luminosity, where BLR radii seem to be smaller than predicted. This is consistent with RM-based claims that high Eddington ratio AGNs show consistently smaller BLR sizes. The BH masses of our targets are also consistent with the standard $M_ BH relation. Model-independent photocentre fitting shows spatial offsets between the hot dust continuum and the BLR photocentres (ranging from sim 17 mu as to 140 mu as) that are generally perpendicular to the alignment of the red- and blueshifted BLR photocentres. These offsets are found to be related to the AGN luminosity and could be caused by asymmetric K-band emission of the hot dust, shifting the dust photocentre. We discuss various possible scenarios that can explain this phenomenon.

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Small telescopes being effective: MAGIC or not?

Afanasiev,

Malygin,

Shablovinskaya

et al. 2023

RAS Techniques and Instruments

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The paper describes the MAGIC multi-mode focal reducer (Monitoring of Active Galaxies by Investigation of their Cores), commissioned on the 1-m Zeiss-1000 telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences in September 2020. Three observational modes are currently realised: photometry, polarimetry, and long-slit spectroscopy. Reducing the focal length makes it possible to obtain a sufficiently large field of view for photometry and a large slit height for spectroscopy of ∼12′, as well as a large field of view for polarimetry with a quadrupole Wollaston prism of ∼6′.4. This feature makes the complex study of extended nebulae and galaxies efficient. The MAGIC capabilities are presented in examples of observations of various astronomical objects. The spectral mode in the range of 4000-7200 ÅÅ provides the spectral resolution R ∼ 1000; 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%. Especially for the new focal reducer, an offset guide and a position angle rotation system were implemented. The results of the modernization of the baffle system in the optical scheme of the telescope for the suppression of scattered light are also described.

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Polarimetric Reverberation Mapping in Medium-Band Filters

Cited by 3 publications

References 65 publications

Optical Spectropolarimetric Variability Properties in Blazars PKS 0637–75 and PKS 1510–089

Optical Spectropolarimetric Variability Properties in Blazars PKS 0637–75 and PKS 1510–089

The size-luminosity relation of local active galactic nuclei from interferometric observations of the broad-line region

Small telescopes being effective: MAGIC or not?

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