Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Spatially resolved origin of millimeter-wave linear polarization in the nuclear region of 3C 84. / Kim, J. -Y.; Krichbaum, T. P.; Marscher, A. P.; Jorstad, S. G.; Agudo, I.; Thum, C.; Hodgson, J. A.; MacDonald, N. R.; Ros, E.; Lu, R. -S.; Bremer, M.; de Vicente, P.; Lindqvist, M.; Trippe, S.; Zensus, J. A.
в: ASTRONOMY & ASTROPHYSICS, Том 622, A196, 01.02.2019.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Spatially resolved origin of millimeter-wave linear polarization in the nuclear region of 3C 84
AU - Kim, J. -Y.
AU - Krichbaum, T. P.
AU - Marscher, A. P.
AU - Jorstad, S. G.
AU - Agudo, I.
AU - Thum, C.
AU - Hodgson, J. A.
AU - MacDonald, N. R.
AU - Ros, E.
AU - Lu, R. -S.
AU - Bremer, M.
AU - de Vicente, P.
AU - Lindqvist, M.
AU - Trippe, S.
AU - Zensus, J. A.
PY - 2019/2/1
Y1 - 2019/2/1
N2 - We report results from a deep polarization imaging of the nearby radio galaxy 3C 84 (NGC 1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86 GHz at an ultrahigh angular resolution of 50 μas (corresponding to ∼200Rs). We also add complementary multiwavelength data from the Very Long Baseline Array (VLBA; 15 and 43 GHz) and from the Atacama Large Millimeter/submillimeter Array (ALMA; 97.5, 233.0 and 343.5 GHz). At 86 GHz, we measured a fractional linear polarization of ∼2% in the VLBI core region. The polarization morphology suggests that the emission is associated with an underlying limb-brightened jet. The fractional linear polarization is lower at 43 and 15 GHz (∼0.3-0.7% and <0.1%, respectively). This suggests an increasing linear polarization degree toward shorter wavelengths on VLBI scales. We also obtain a large rotation measure (RM) of ∼10 5-6 rad m 2 in the core at 43 GHz. Moreover, the VLBA 43 GHz observations show a variable RM in the VLBI core region during a small flare in 2015. Faraday depolarization and Faraday conversion in an inhomogeneous and mildly relativistic plasma could explain the observed linear polarization characteristics and the previously measured frequency dependence of the circular polarization. Our Faraday depolarization modeling suggests that the RM most likely originates from an external screen with a highly uniform RM distribution. To explain the large RM value, the uniform RM distribution and the RM variability, we suggest that the Faraday rotation is caused by a boundary layer in a transversely stratified jet. Based on the RM and the synchrotron spectrum of the core, we provide an estimate for the magnetic field strength and the electron density of the jet plasma.
AB - We report results from a deep polarization imaging of the nearby radio galaxy 3C 84 (NGC 1275). The source was observed with the Global Millimeter VLBI Array (GMVA) at 86 GHz at an ultrahigh angular resolution of 50 μas (corresponding to ∼200Rs). We also add complementary multiwavelength data from the Very Long Baseline Array (VLBA; 15 and 43 GHz) and from the Atacama Large Millimeter/submillimeter Array (ALMA; 97.5, 233.0 and 343.5 GHz). At 86 GHz, we measured a fractional linear polarization of ∼2% in the VLBI core region. The polarization morphology suggests that the emission is associated with an underlying limb-brightened jet. The fractional linear polarization is lower at 43 and 15 GHz (∼0.3-0.7% and <0.1%, respectively). This suggests an increasing linear polarization degree toward shorter wavelengths on VLBI scales. We also obtain a large rotation measure (RM) of ∼10 5-6 rad m 2 in the core at 43 GHz. Moreover, the VLBA 43 GHz observations show a variable RM in the VLBI core region during a small flare in 2015. Faraday depolarization and Faraday conversion in an inhomogeneous and mildly relativistic plasma could explain the observed linear polarization characteristics and the previously measured frequency dependence of the circular polarization. Our Faraday depolarization modeling suggests that the RM most likely originates from an external screen with a highly uniform RM distribution. To explain the large RM value, the uniform RM distribution and the RM variability, we suggest that the Faraday rotation is caused by a boundary layer in a transversely stratified jet. Based on the RM and the synchrotron spectrum of the core, we provide an estimate for the magnetic field strength and the electron density of the jet plasma.
KW - galaxies: active
KW - galaxies: jets
KW - galaxies: individual: NGC 1275
KW - galaxies: individual: 3C 84
KW - techniques: interferometric
KW - techniques: polarimetric
KW - ACTIVE GALACTIC NUCLEI
KW - MAGNETIC-FIELD STRUCTURE
KW - SAGITTARIUS-A-ASTERISK
KW - GAMMA-RAY EMISSION
KW - FARADAY-ROTATION
KW - CIRCULAR-POLARIZATION
KW - RADIO-SOURCES
KW - POLARIMETRIC OBSERVATIONS
KW - HIGH-FREQUENCIES
KW - ACCRETION FLOWS
KW - Techniques: interferometric
KW - Techniques: polarimetric
KW - Galaxies: individual: NGC 1275
KW - Galaxies: active
KW - Galaxies: individual: 3C 84
KW - Galaxies: jets
UR - http://www.scopus.com/inward/record.url?scp=85062028257&partnerID=8YFLogxK
UR - http://www.mendeley.com/research/spatially-resolved-origin-millimeterwave-linear-polarization-nuclear-region-3c-84
U2 - 10.1051/0004-6361/201832920
DO - 10.1051/0004-6361/201832920
M3 - статья
VL - 622
JO - ASTRONOMY & ASTROPHYSICS
JF - ASTRONOMY & ASTROPHYSICS
SN - 0004-6361
M1 - A196
ER -
ID: 40876251