VizieR Online Data Catalog: High cadence polarization monitoring of OJ287 (Myserlis+, 2018)
Abstract
We used the recently developed, high-precision data analysis methodology presented in Myserlis et al. (2018A&A...609A..68M, Cat. J/A+A/609/A68) to recover all four Stokes parameters. The methodology is aimed on the effective treatment of the instrumental linear and circular polarization to reach a precision of 0.001-0.002 in fractional polarization and 1° in polarization angle. We recovered the total flux density of OJ287 at nine bands from 2.64GHz to 43GHz, the linear polarization parameters at four bands between 2.64GHz and 10.45GHz, and the circular polarization at two bands, 4.85GHz and 8.35GHz. The data were obtained between December 2015 and January 2017 (MJD 57370-57785) with mean cadence of ten days. The corresponding light curves are plotted in Fig. 1 of the paper.
In order to constrain the region around the jet core where the long EVPA rotation happens, we examined concurrent interferometric datasets obtained by the Very Long Baseline Array (VLBA). We analyzed six data sets at 15 GHz obtained by the MOJAVE monitoring program (Lister et al., 2018ApJS..234...12L, Cat. J/ApJS/234/12) from July 20, 2015 to January 28, 2017 (MJD 57223-57781) and 17 data sets at 43 GHz obtained by the Boston University VLBA blazar monitoring program from July 2, 2015 to January 14, 2017 (MJD 57205-57767). We first created the Stokes I, Q and U maps using the corresponding visibility data that we retrieved from the online archives. In Fig. 5 of the paper we show a sample polarized map at each frequency. All images are included in the current dataset. Then, we transformed the data from Jy/beam to Jy. Finally, we calculated the integrated Stokes I, Q and U within predefined circular areas around the core position (i.e. the location of the peak flux) with radii between 0.05 and 2mas in 0.05mas steps. The results were used to estimate the integrated polarized flux, polarization degree and EVPA within each circular area. Here we report the integrated values for the area with the minimum radius which shows the long EVPA rotation, namely 0.10mas for the 15GHz data and 0.15mas for the 43GHz data. For the 43GHz data we report also the integrated values over the largest circular area of 2mas radius which encircles the whole extend of the source at that frequency. The corresponding light curves are plotted in Fig. 6 of the paper. All EVPA measurements are corrected for the n-pi ambiguity effect by minimizing the variations between consecutive data points after accounting for their uncertainties. (9 data files).- Publication:
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VizieR Online Data Catalog
- Pub Date:
- October 2018
- DOI:
- 10.26093/cds/vizier.36190088
- Bibcode:
- 2018yCat..36190088M
- Keywords:
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- Active gal. nuclei;
- BL Lac objects;
- Polarization;
- Radio continuum;
- VLBI;
- Radio sources;
- Millimetric/submm sources