2018A&A...609A..68M


Query : 2018A&A...609A..68M

2018A&A...609A..68M - Astronomy and Astrophysics, volume 609A, 68-68 (2018/1-1)

Full-Stokes polarimetry with circularly polarized feeds. Sources with stable linear and circular polarization in the GHz regime.

MYSERLIS I., ANGELAKIS E., KRAUS A., LIONTAS C.A., MARCHILI N., ALLER M.F., ALLER H.D., KARAMANAVIS V., FUHRMANN L., KRICHBAUM T.P. and ZENSUS J.A.

Abstract (from CDS):

We present an analysis pipeline that enables the recovery of reliable information for all four Stokes parameters with high accuracy. Its novelty relies on the effective treatment of the instrumental effects even before the computation of the Stokes parameters, contrary to conventionally used methods such as that based on the Muller matrix. For instance, instrumental linear polarization is corrected across the whole telescope beam and significant Stokes Q and U can be recovered even when the recorded signals are severely corrupted by instrumental effects. The accuracy we reach in terms of polarization degree is of the order of 0.1-0.2%. The polarization angles are determined with an accuracy of almost 1°. The presented methodology was applied to recover the linear and circular polarization of around 150 active galactic nuclei, which were monitored between July 2010 and April 2016 with the Effelsberg 100-m telescope at 4.85GHz and 8.35GHz with a median cadence of 1.2 months. The polarized emission of the Moon was used to calibrate the polarization angle measurements. Our analysis showed a small system-induced rotation of about 1° at both observing frequencies. Over the examined period, five sources have significant and stable linear polarization; three sources remain constantly linearly unpolarized; and a total of 11 sources have stable circular polarization degree mc, four of them with non-zero mc. We also identify eight sources that maintain a stable polarization angle. All this is provided to the community for future polarization observations reference. We finally show that our analysis method is conceptually different from those traditionally used and performs better than the Muller matrix method. Although it has been developed for a system equipped with circularly polarized feeds, it can easily be generalized to systems with linearly polarized feeds as well.

Abstract Copyright: © ESO, 2018

Journal keyword(s): polarization - techniques: polarimetric - galaxies: active - radio continuum: galaxies - methods: data analysis - galaxies: jets

VizieR on-line data: <Available at CDS (J/A+A/609/A68): sources.dat figc1.dat>

Simbad objects: 25

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Number of rows : 25
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
#notes
1 3C 48 QSO 01 37 41.2996631208 +33 09 35.080388820   16.62 16.20     ~ 2708 2
2 QSO B0218+357 QSO 02 21 05.4920852208 +35 56 13.848581904   20.0 20.0 19.60   ~ 532 3
3 4C 28.07 QSO 02 37 52.40567519 +28 48 08.9899986     18.5 16.99   ~ 565 1
4 QSO B0235+1624 BLL 02 38 38.93010450 +16 36 59.2745528   16.46 15.50 15.92   ~ 1468 2
5 NGC 1052 GiP 02 41 04.79849989 -08 15 20.7519527 11.84 11.41 10.47 10.71   ~ 1249 2
6 3C 84 Sy2 03 19 48.1599902040 +41 30 42.108850836   13.10 12.48 11.09   ~ 3837 3
7 4C 50.11 QSO 03 59 29.74727351 +50 57 50.1618607           ~ 421 1
8 QSO J0530+13 Bla 05 30 56.41674741 +13 31 55.1494688     20.0 19.35   ~ 921 1
9 2C 553 QSO 06 27 10.1 -05 53 06           ~ 153 1
10 4C 71.07 QSO 08 41 24.36528508 +70 53 42.1730435     16.5 16.8   ~ 737 1
11 QSO J0854+2006 BLL 08 54 48.8749846272 +20 06 30.639583620   15.91 15.43 15.56   ~ 2211 1
12 QSO J1130-1449 QSO 11 30 07.0523452128 -14 49 27.388021944   17.17 16.90 16 16.97 ~ 672 1
13 3C 273 BLL 12 29 06.6998257176 +02 03 08.597629980   13.05 14.830 14.11   ~ 5620 1
14 3C 279 Bla 12 56 11.16657958 -05 47 21.5251510   18.01 17.75 15.87   ~ 2911 2
15 3C 286 Sy1 13 31 08.2883506368 +30 30 32.960091564   17.51 17.25     ~ 4150 2
16 3C 295 Sy2 14 11 20.467 +52 12 09.52   22.34 20.80 18.54   ~ 949 5
17 QSO J1512-0906 Bla 15 12 50.53293048 -09 05 59.8297908   16.74 16.54     ~ 1251 1
18 4C 38.41 QSO 16 35 15.49297809 +38 08 04.5005995   18.14 17.97 17.25   ~ 816 1
19 3C 345 QSO 16 42 58.80997043 +39 48 36.9939552   16.81 16.59 16.84   ~ 1650 2
20 4C 39.49 BLL 16 53 52.21668403 +39 45 36.6088754 14.09 14.15 13.29 8.26   ~ 2053 2
21 QSO B1730-130 QSO 17 33 02.70578907 -13 04 49.5482119   18 18.5 18.78 17.39 ~ 1083 1
22 NGC 7027 PN 21 07 01.571952 +42 14 10.47120   10.358 8.831 10.157   ~ 2413 1
23 NAME BL Lac BLL 22 02 43.2913536816 +42 16 39.979416792   15.66 14.72     ~ 2163 1
24 4C 11.69 QSO 22 32 36.40890093 +11 43 50.9040592   17.75 17.33     ~ 1062 2
25 3C 454.3 Bla 22 53 57.7480438728 +16 08 53.561508864   16.57 16.10 15.22   ~ 2719 2

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2022.12.09-07:08:05

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