2018A&A...610A..32B


Query : 2018A&A...610A..32B

2018A&A...610A..32B - Astronomy and Astrophysics, volume 610A, 32-32 (2018/2-1)

VLBA polarimetric monitoring of 3C 111.

BEUCHERT T., KADLER M., PERUCHO M., GROSSBERGER C., SCHULZ R., AGUDO I., CASADIO C., GOMEZ J.L., GURWELL M., HOMAN D., KOVALEV Y.Y., LISTER M.L., MARKOFF S., MOLINA S.N., PUSHKAREV A.B., ROS E., SAVOLAINEN T., STEINBRING T., THUM C. and WILMS J.

Abstract (from CDS):

Context. While studies of large samples of jets of active galactic nuclei (AGN) are important in order to establish a global picture, dedicated single-source studies are an invaluable tool for probing crucial processes within jets on parsec scales. These processes involve in particular the formation and geometry of the jet magnetic field as well as the flow itself.
Aims. We aim to better understand the dynamics within relativistic magneto-hydrodynamical flows in the extreme environment and close vicinity of supermassive black holes.
Methods. We analyze the peculiar radio galaxy 3C 111, for which long-term polarimetric observations are available. We make use of the high spatial resolution of the VLBA network and the MOJAVE monitoring program, which provides high data quality also for single sources and allows us to study jet dynamics on parsec scales in full polarization with an evenly sampled time-domain. While electric vectors can probe the underlying magnetic field, other properties of the jet such as the variable (polarized) flux density, feature size, and brightness temperature, can give valuable insights into the flow itself. We complement the VLBA data with data from the IRAM 30-m Telescope as well as the SMA.
Results. We observe a complex evolution of the polarized jet. The electric vector position angles (EVPAs) of features traveling down the jet perform a large rotation of ≥180° across a distance of about 20pc. As opposed to this smooth swing, the EVPAs are strongly variable within the first parsecs of the jet. We find an overall tendency towards transverse EVPAs across the jet with a local anomaly of aligned vectors in between. The polarized flux density increases rapidly at that distance and eventually saturates towards the outermost observable regions. The transverse extent of the flow suddenly decreases simultaneously to a jump in brightness temperature around where we observe the EVPAs to turn into alignment with the jet flow. Also the gradient of the feature size and particle density with distance steepens significantly at that region.
Conclusions. We interpret the propagating polarized features as shocks and the observed local anomalies as the interaction of these shocks with a localized recollimation shock of the underlying flow. Together with a sheared magnetic field, this shock-shock interaction can explain the large rotation of the EVPA. The superimposed variability of the EVPAs close to the core is likely related to a clumpy Faraday screen, which also contributes significantly to the observed EVPA rotation in that region.

Abstract Copyright: © ESO 2018

Journal keyword(s): galaxies: active - galaxies: jets - galaxies: individual: 3C 111 - galaxies: magnetic fields - radio continuum: galaxies - polarization

Simbad objects: 10

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Number of rows : 10
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 NGC 1052 GiP 02 41 04.79851 -08 15 20.7517 11.84 11.41 10.47 10.71   ~ 1194 2
2 3C 111 Sy1 04 18 21.2773655604 +38 01 35.801523843   19.75 18.05     ~ 880 1
3 Mrk 1506 Sy1 04 33 11.0958197353 +05 21 15.617543663   15.72 15.05 10.08   ~ 1891 2
4 ICRF J103351.4+605107 Sy1 10 33 51.4290811577 +60 51 07.335485597   19.31 18.86 20.24   ~ 136 2
5 M 87 BiC 12 30 49.42338230 +12 23 28.0438581 10.16 9.59 8.63   7.49 ~ 6496 3
6 3C 279 Bla 12 56 11.1664521013 -05 47 21.531840471   18.01 17.75 15.87   ~ 2816 2
7 QSO J1512-0906 Bla 15 12 50.53292491 -09 05 59.8295878   16.74 16.54     ~ 1201 1
8 8C 1803+784 BLL 18 00 45.6831135718 +78 28 04.017792333   16.4 16.4 15.46   ~ 682 1
9 NAME BL Lac BLL 22 02 43.2913773726 +42 16 39.978417860   15.66 14.72     ~ 2083 1
10 4C 11.69 QSO 22 32 36.40890517 +11 43 50.9040717   17.75 17.33     ~ 1017 2

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2021.10.18-03:51:05

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