2020A&A...636A..79C


Query : 2020A&A...636A..79C

2020A&A...636A..79C - Astronomy and Astrophysics, volume 636A, 79-79 (2020/4-1)

180° rotations in the polarization angle for blazars.

COHEN M.H. and SAVOLAINEN T.

Abstract (from CDS):

Rotations of the electric vector position angle (EVPA) in blazars are often close to an integral multiple of 180°. There are many examples of this in the literature, and we strengthen the evidence by showing that, in the RoboPol monitoring program, nπ rotations occur more frequently than otherwise expected by chance. We explain this using a model consisting of two polarized emission components: a "jet" that is constant in time and a "burst" that is variable. The EVPA of the combination is EVPAjet at both the beginning and the end of the burst, so the net rotation across the burst must be nπ. Several examples of this model are analyzed on the Stokes plane, where the winding number for the Stokes vector of the combination gives the value of n. The main conclusion is that the EVPA rotation can be much larger than the physical rotation of the emission region around the axis of the jet, but this requires the EVPAs of the jet and the burst to be nearly orthogonal. Shock-in-jet calculations can provide a physical model for our toy model and in addition they automatically give the required orthogonality. The model is illustrated with data from the literature on OJ 287. We suggest that the large rapid EVPA rotation seen in OJ 287 might be a phase effect and not representative of a physical rotation.

Abstract Copyright: © ESO 2020

Journal keyword(s): polarization - galaxies: jets - galaxies: active - BL Lacertae objects: individual: OJ 287

Simbad objects: 23

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Number of rows : 23
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 2FGL J0045.3+2127 BLL 00 45 19.2978209676 +21 27 39.998419481 17.37 17.33 17.01 17.3   ~ 61 1
2 QSO B0133+476 Bla 01 36 58.59480585 +47 51 29.1000445     18.0 19.25 15.21 ~ 464 1
3 8C 0716+714 BLL 07 21 53.4484901266 +71 20 36.362058601   15.5 14.17 14.27   ~ 1177 1
4 QSO J0730-116 QSO 07 30 19.11247420 -11 41 12.6005110     20.30 20.3   ~ 277 1
5 QSO J0854+2006 BLL 08 54 48.8749311881 +20 06 30.642936668   15.91 15.43 15.56   ~ 2111 1
6 6C 095456+654857 BLL 09 58 47.2452838930 +65 33 54.821524491     17.0 15.75   ~ 640 1
7 6C 101157+494057 BLL 10 15 04.1393763275 +49 26 00.708524180   16.56 16.15 14.58   ~ 322 2
8 3C 279 Bla 12 56 11.1664521013 -05 47 21.531840471   18.01 17.75 15.87   ~ 2817 2
9 QSO B1502+1041 Bla 15 04 24.97978142 +10 29 39.1986151   18.97 18.56 18.94   ~ 495 1
10 QSO J1512-0906 Bla 15 12 50.53292491 -09 05 59.8295878   16.74 16.54     ~ 1201 1
11 QSO B1553+113 BLL 15 55 43.0439413597 +11 11 24.365587666 14.91 14.72 14.57 13.99   ~ 452 1
12 7C 1557+5633 BLL 15 58 48.2888061057 +56 25 14.120355021   18.08 17.54 17.2   ~ 75 1
13 4C 38.41 QSO 16 35 15.492970280 +38 08 04.50062279   18.14 17.97 17.25   ~ 782 1
14 7C 1749+7006 BLL 17 48 32.8399653579 +70 05 50.768853537   17.46 17.01 15.48   ~ 396 1
15 4C 09.57 BLL 17 51 32.81857318 +09 39 00.7284829   17.46 16.78 15.57   ~ 853 1
16 8C 1803+784 BLL 18 00 45.6831135718 +78 28 04.017792333   16.4 16.4 15.46   ~ 682 1
17 3C 371 BLL 18 06 50.6803567107 +69 49 28.108152993   14.77 14.22 11.39   ~ 813 2
18 2MASS J18362123+3136268 BLL 18 36 21.2402542219 +31 36 26.726597152           ~ 37 1
19 6C 192647+611105 BLL 19 27 30.4437056728 +61 17 32.874367712   17.5 17.5 16.99   ~ 102 1
20 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 2083 1
21 4C 11.69 QSO 22 32 36.40890517 +11 43 50.9040717   17.75 17.33     ~ 1018 2
22 87GB 224130.7+200514 BLL 22 43 54.7434952027 +20 21 03.773522952     16.00 16.1   ~ 80 0
23 3C 454.3 Bla 22 53 57.74798 +16 08 53.5611   16.57 16.10 15.22   ~ 2609 2

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2021.10.27-11:16:58

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