J/ApJ/808/162 VLBA 15 and 43GHz obs. of 3C 120 (Casadio+, 2015)
The connection between the radio jet and the gamma-ray emission in
the radio galaxy 3C 120.
Casadio C., Gomez J.L., Grandi P., Jorstad S.G., Marscher A.P.,
Lister M.L., Kovalev YU.Y., Savolainen T., Pushkarev A.B.
<Astrophys. J., 808, 162 (2015)>
=2015ApJ...808..162C 2015ApJ...808..162C (SIMBAD/NED BibCode)
ADC_Keywords: Galaxies, radio ; Active gal. nuclei ; Radio continuum ;
Gamma rays
Keywords: galaxies: active; galaxies: individual: 3C120;
galaxies: jets; radio continuum: galaxies
Abstract:
We present the analysis of the radio jet evolution of the radio galaxy
3C 120 during a period of prolonged γ-ray activity detected by
the Fermi satellite between 2012 December and 2014 October. We find a
clear connection between the γ-ray and radio emission, such that
every period of γ-ray activity is accompanied by the flaring of
the millimeter very long baseline interferometry (VLBI) core and
subsequent ejection of a new superluminal component. However, not all
ejections of components are associated with γ-ray events
detectable by Fermi. Clear γ-ray detections are obtained only
when components are moving in a direction closer to our line of sight.
This suggests that the observed γ-ray emission depends not only
on the interaction of moving components with the millimeter VLBI core,
but also on their orientation with respect to the observer. Timing of
the γ-ray detections and ejection of superluminal components
locate the γ-ray production to within ∼0.13pc from the
millimeter VLBI core, which was previously estimated to lie about
0.24pc from the central black hole. This corresponds to about twice
the estimated extension of the broad line region, limiting the
external photon field and therefore suggesting synchrotron self
Compton as the most probable mechanism for the production of the
γ-ray emission. Alternatively, the interaction of components
with the jet sheath can provide the necessary photon field to produced
the observed γ-rays by Compton scattering.
Description:
To study the structure of the radio jet in 3C 120 we have collected
data from two of the most extended Very Long Baseline Array (VLBA)
monitoring programs: the MOJAVE and the VLBA-BU-BLAZAR programs.
This radio data set consists of 46 epochs of VLBA data at 15GHz taken
from the MOJAVE survey, covering the observing period from 2008 June
to 2013 August, and 21 epochs of VLBA data at 43GHz from the
VLBA-BU-BLAZAR program, covering the period from 2012 January to 2014
May.
The Fermi-LAT data was collected during 72 months of operation (from
2008 August 4 to 2014 August 4).
Objects:
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RA (ICRS) DE Designation(s)
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04 33 11.10 +05 21 15.6 3C 120 = QSO J0433+0521
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 70 366 VLBA 15GHz model-fit components' parameters
table2.dat 69 99 VLBA 43GHz model-fit components' parameters
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See also:
J/ApJ/798/134 : MOJAVE. XII. Acceleration of blazar jets (Homan+, 2015)
J/AJ/146/120 : MOJAVE. X. Parsec-scale kinematics of AGNs (Lister+, 2013)
J/MNRAS/430/60 : Suzaku view of highly ionized outflows in AGN (Gofford+, 2013)
J/A+A/544/A18 : Radio galaxies of the local universe (van Velzen+, 2012)
J/ApJ/754/23 : Blazar submm + γ-ray luminosities (Leon-Tavares+, 2012)
J/ApJS/199/31 : Fermi LAT second source catalog (2FGL) (Nolan+, 2012)
J/ApJS/194/29 : Observations of blazars at 15GHz (Richards+, 2011)
J/ApJ/743/171 : The 2LAC catalog (Ackermann+, 2011)
J/ApJ/742/27 : 15GHz and jet properties of MOJAVE blazars (Lister+, 2011)
J/ApJ/734/43 : X-ray, optical & radio monitoring of 3C111 (Chatterjee+, 2011)
J/ApJ/706/1253 : MOJAVE VII. Blazar jet acceleration (Homan+, 2009)
J/AJ/138/1874 : MOJAVE. VI. Kinematic analysis of blazar jets (Lister+, 2009)
J/AJ/137/3718 : 15GHz monitoring of AGN jets with VLBA (Lister+, 2009)
J/PAZh/35/403 : Optical Variabilities in 3C 120 (Doroshenko+, 2009)
J/other/ChJAA/8.385 : Superluminal motion in AGN (Zhang+, 2008)
J/AJ/134/799 : Multiwaveband polarimetry of 15 AGN (Jorstad+, 2007)
J/AJ/130/1418 : AGN jet kinematics (Jorstad+, 2005)
J/A+AS/122/271 : mm-monitoring of radio sources IV. (Reuter+ 1997)
J/ApJS/51/67 : 5 GHz Observations of Arecibo 611 MHz Sources (Lawrence+ 1983)
http://www.physics.purdue.edu/MOJAVE : MOJAVE home page
http://www.bu.edu/blazars/research.html : BU blazar group home page
Byte-by-byte Description of file: table[12].dat
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Bytes Format Units Label Explanations
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1- 7 F7.2 yr Obs.Y Decimal year of the observation
9- 16 F8.2 d MJD Modified Julian Date of the observation
18- 21 A4 --- Name Component identifier
23- 29 F7.2 mJy Flux [0.08/1489] Observed flux density
31- 32 I2 mJy e_Flux [1/74] Uncertainty in Flux
34- 38 F5.2 mas D [0.07/17]? Distance from the C0 component
40- 43 F4.2 mas e_D [0.01/2]? Uncertainty in D
45- 51 F7.2 deg PA [-131/-95]? Position angle
53- 56 F4.1 deg e_PA [0.6/29]? Uncertainty in PA
58- 58 A1 --- l_FWHM Limit flag on FWHM
60- 64 F5.2 mas FWHM [0.03/4] Component Full-Width at Half-Maximum
66- 70 F5.3 mas e_FWHM [0.01/4]? Uncertainty in FWHM
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 01-Dec-2015