J/A+A/698/A210 3C 273 multi-frequency polarimetric images (Toscano+, 2025)
Helical magnetic field structure in 3C 273.
A Faraday rotation analysis using multi-frequency polarimetric VLBA data.
Toscano T., Molina S.N., Gomez J.L., Zeng A.-L., Dahale R., Cho I.,
Moriyama K., Wielgus M., Fuentes A., Foschi M., Roeder J., Myserlis I.,
Angelakis E., Zensus A.
<Astron. Astrophys. 698, A210 (2025)>
=2025A&A...698A.210T 2025A&A...698A.210T (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei ; QSOs ; VLBI ; Polarization
Keywords: methods: observational - techniques: interferometric -
techniques: polarimetric - galaxies: jets -
galaxies: magnetic fields - quasars: general
Abstract:
We present a study on rotation measure (RM) of the quasar 3C 273. This
analysis aims to discern the magnetic field structure and its temporal
evolution. The quasar 3C 273 is one of the most studied active
galactic nuclei due to its high brightness, strong polarization, and
proximity, which enables resolving the transverse structure of its jet
in detail. We used polarized data from 2014, collected at six
frequencies (5, 8, 15, 22, 43, 86 GHz) with the Very Long Baseline
Array, to produce total and linear polarization intensity images, as
well as RM maps. Our analysis reveals a well-defined transverse RM
gradient across the jet, indicating a helical, ordered magnetic field
that threads the jet and likely contributes to its collimation.
Furthermore, we identified temporal variations in the RM magnitude
when compared with prior observations. These temporal variations show
that the environment around the jet is dynamic, with changes in the
density and magnetic field strength of the sheath that are possibly
caused by interactions with the surrounding medium.
Description:
The observations presented in this work were conducted on 2014,
November 21, using the Very Long Baseline Array (VLBA) as part of an
astrometric multi-frequency program (with reference BG216).
All 10 VLBA antennas were present during the observation, which
spanned six frequencies: 4.98, 8.42, 15.25, 21.89, 43.79 and 87.55GHz.
The data were recorded in 8 IFs of 32MHz, amounting to 256MHz total
bandwidth per frequency. The on-source time ranged from 10 minutes at
the lower three frequencies, to 4h 46m at 22GHz, and 47m at the
highest two frequencies.
VLBA data of the 3C 273 images displayed in the paper (Fig. 1) at 6
different frequencies. Each name of the files include the name of the
source (3c273) and the corresponding frequency. For example, at 5GHz
the name is "3c273_5GHz.uvf"
Objects:
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RA (2000) DE Designation(s)
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12 29 06.69 +02 03 08.5 3C 273 = SDSS J122906.69+020308.5
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 95 6 List of fits images
fits/* . 6 Individual fits images
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See also:
J/MNRAS/392/1181 : BV(RI)c photometry of 3C 273 (Dai+, 2009)
J/ApJS/213/26 : Optical light curves of PHL 1811 and 3C 273 (Fan+, 2014)
J/A+A/576/A122 : 3C 273 high energy spectrum (Esposito+, 2015)
J/A+A/601/A35 : High-fidelity VLA imaging of 3C 273 (Perley+, 2017)
J/A+A/604/A111 : 22GHz image of 3C 273 (Bruni+, 2017)
J/ApJS/229/21 : VRI monitoring of the QSO 3C 273 in 2005-2016 (Xiong+, 2017)
J/ApJ/876/49 : 3C 273 10yr reverberation mapping campaign (Zhang+, 2019)
J/ApJ/880/155 : RI photometry of blazars S5 0716+714 and 3C 273 (Liu+, 2019)
J/A+A/636/A62 : Light curves of 3C273 during 2015-2019 (Kim+, 2020)
J/AJ/159/259 : Quasar 3C 273 opt-NIR light curve (Sobrino Figaredo+, 2020)
J/ApJ/897/18 : Swift UVOT observation of radio quasar 3C 273 (Li+, 2020)
J/A+A/658/A8 : Resolved jet of 3C 273 at 150MHz (Harwood+, 2022)
J/A+A/683/L5 : FITS images of 3C 273 host galaxy (Ren+, 2024)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 2 I2 h RAh Simbad Right ascension (J2000)
4- 5 I2 min RAm Simbad Right ascension (J2000)
7- 11 F5.2 s RAs Simbad Right ascension (J2000)
12 A1 --- DE- Simbad declination sign (J2000)
13- 14 I2 deg DEd Simbad declination (J2000)
16- 17 I2 arcmin DEm Simbad declination (J2000)
19- 22 F4.1 arcsec DEs Simbad declination (J2000)
24- 33 A10 "date" Obs.date Observation date
35- 45 E11.6 Hz Freq Observed frequency
47- 50 I4 Kibyte size Size of FITS file
52- 66 A15 --- FileName Name of FITS file, in subdirectory fits
68- 95 A28 --- Title Title of the FITS file
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Acknowledgements:
Teresa Toscano, ttoscano(at)iaa.es
(End) Patricia Vannier [CDS] 05-May-2025