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J/MNRAS/469/4034    Broadband polarisation of radio AGN      (O'Sullivan+, 2017)

Broadband, radio spectro-polarimetric study of 100 radiative-mode and jet-mode AGN. O'Sullivan S.P., Purcell C.R., Anderson C.S., Farnes J.S., Sun X.H., Gaensler B.M. <Mon. Not. R. Astron. Soc. 469, 4034 (2017)> =2017MNRAS.469.4034O (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; Polarization Keywords: radio continuum: galaxies - galaxies: magnetic fields - techniques: polarimetric - galaxies: jet - galaxies: active Abstract: We present the results from a broadband (1 to 3GHz), spectro-polarimetry study of the integrated emission from 100 extragalactic radio sources with the ATCA, selected to be highly linearly polarized at 1.4 GHz. We use a general purpose, polarization model-fitting procedure that describes the Faraday rotation measure (RM) and intrinsic polarization structure of up to three distinct polarized emission regions or 'RM components' of a source. Overall, 37%/52%/11% of sources are best fit by one/two/three RM components. However, these fractions are dependent on the signal-to-noise ratio (S/N) in polarization (more RM components more likely at higher S/N). In general, our analysis shows that sources with high integrated degrees of polarization at 1.4GHz have low Faraday depolarization, are typically dominated by a single RM component, have a steep spectral index, and a high intrinsic degree of polarization. After classifying our sample into radiative-mode and jet-mode AGN, we find no significant difference between the Faraday rotation or Faraday depolarization properties of jet-mode and radiative-mode AGN. However, there is a statistically significant difference in the intrinsic degree of polarization between the two types, with the jet-mode sources having more intrinsically ordered magnetic field structures than the radiative-mode sources. We also find a preferred perpendicular orientation of the intrinsic magnetic field structure of jet-mode AGN with respect to the jet direction, while no clear preference is found for the radiative-mode sources. Description: Linear polarisation data as a function of wavelength-squared for 100 extragalactic radio sources, selected to be highly polarised at 1.4GHz. The data presented here were obtained using the Australia Telescope Compact Array (ATCA) over 1.1-3.1GHz (16cm) with 1MHz spectral resolution between 2014 April 19-28. The integrated emission from each source, imaged at 10 MHz intervals, is presented below. See Section 2 for details. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table2.dat 88 100 Basic properties of all sources in the sample tablea1.dat 85 16241 The spectropolarimetric data
See also: J/ApJS/45/97 : Extragal. Radio Sources Faraday Rot. (Simard-Normandin+ 1981) J/ApJ/707/114 : Faraday rotation in Cen A (Feain, 2009) J/MNRAS/421/3300 : Complex Faraday depth structure of AGN (O'Sullivan+, 2012) J/ApJ/759/25 : Rotation measures at 1.4GHz toward the LMC (Mao+, 2012) J/AJ/144/105 : MOJAVE. VIII. Faraday rotation in AGN jets. (Hovatta+, 2012) J/AJ/149/60 : Modeling Faraday structures. I. 1100-1400 MHz (Sun+, 2015) J/ApJ/825/59 : A Study of Broadband Faraday Rotation (Anderson+, 2016) Byte-by-byte Description of file: table2.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Source name (JHHMM+DDMM) 12- 18 F7.3 deg RAdeg Right ascension (J2000) 20- 26 F7.3 deg DEdeg Declination (J2000) 28- 32 F5.2 --- alpha Spectral index 34- 37 I4 mJy I2.1GHz Integrated total intensity at 2.1GHz 39- 43 F5.3 --- z Redshift 45- 49 F5.1 rad/m2 |RRM| Absolute value of the residual rotation measure 51- 54 F4.1 rad/m2 sRMw Polarization-weighted RM dispersion 56- 59 F4.1 rad/m2 DRMw Polarization-weighted RM gradient 61- 64 F4.1 % <p0> Mean intrinsic degree of polarization 66- 67 I2 --- S/N Polarization signal-to-noise ratio 69 I1 --- N Number of RM components 71- 75 F5.2 --- beta Polarization spectral index 77- 81 A5 --- Morph Total intensity morphology 83 A1 --- l_l Limit flag on l 84- 86 I3 kpc l Linear size 88 A1 --- Rad/Jet [0/1] Radiatice (0) or jet (1) mode
Byte-by-byte Description of file: tablea1.dat
Bytes Format Units Label Explanations
1- 10 A10 --- Name Source name (JHHMM+DDMM) 17- 25 F9.7 m2 lsq [0.001/0.06] Wavelength squared 31- 40 F10.7 --- q Stokes Q/I data (fractional) 46- 55 F10.7 --- u Stokes U/I data (fractional) 60- 70 F11.7 --- e_q ?=-99 Uncertainty in Q/I (fractional) 75- 85 F11.7 --- e_u ?=-99 Uncertainty in U/I (fractional)
Acknowledgements: Shane O'Sullivan, shane(at)
(End) Shane O'Sullivan [IA-UNAM], Patricia Vannier [CDS] 17-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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