J/A+A/658/A119 Jet collimation in NGC 1052 (Baczko+, 2022)
Ambilateral collimation study of the twin-jets in NGC 1052.
Baczko A.-K., Ros E., Kadler M., Fromm C.M., Boccardi B., Perucho M.,
Krichbaum T.P., Burd P.R., Zensus J.A.
<Astron. Astrophys. 658, A119 (2022)>
=2022A&A...658A.119B 2022A&A...658A.119B (SIMBAD/NED BibCode)
ADC_Keywords: Active gal. nuclei; Galaxies, radio ; VLBI
Keywords: techniques: high angular resolution - galaxies: active -
galaxies: jets
Abstract:
With the increased sensitivity and resolution of radio interferometry
the study of the collimation and acceleration region of jets in Active
Galactic Nuclei(AGN) has come into focus within the last years.
Whereas a large fraction of AGN jets reveal a change from parabolic to
conical collimation around the Bondi radius, a small number of sources
deviate from this standard picture, including the radio galaxy
NGC1052.
We study the jet width profile, which provides valuable information
about the interplay between the central engine and accretion disk
system and the collimation and acceleration zone of the jets.
We observed the double-sided active galaxy NGC1052 at six frequencies
with the VLBA in 2017 and at 22GHz with RadioAstron in 2016. These
data are combined with archival 15, 22, and 43GHz multi-epoch VLBA
observations. From ridge-line fitting we obtained width measurements
along the jet and counter-jet which were fitted with broken
power-laws.
We find a break in the jet collimation profile at ∼104Rs
(Schwarzschild radii). Downstream of the break the collimation is
conical with a power-law index of 1.0-1.2 (cylindrical 0; parabolic
0.5; conical 1). The upstream power-law index of 0.36 for the
approaching jet is neither cylindrical nor parabolic and for the
receding jet with 0.16 close-to cylindrical. Both jets have an opening
angle of ∼30 degree at a distance of ∼10^3RS and are well collimated
with an opening angle of <10 degrees downstream of the break. There
are significant differences in the upstream collimation profile
between approaching (Eastern) and receding (Western) jet. Absorption
or scattering in the surrounding torus as well as an accretion wind
may mimic a cylindrical profile.
We need to increase the observing frequencies, which do not suffer
from absorption to find the true jet collimation profile upstream of
104Rs.
Description:
VLBI Clean images of NGC1052 in fits-format; VLBA observations at 1.4,
5, 8, 15, 22, and 43GHz; stacked VLBA images at 15, 22, and 43GHz,
Global array image at 22GHz.
Objects:
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RA (2000) DE Designation(s)
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02 41 04.80 -08 15 20.8 NGC 1052 = LEDA 10175
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 107 10 List of fits images
fits/* . 10 Individual fits images
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See also:
J/A+A/623/A27 : NGC1052 twin-jet VLBI images (Baczko+, 2019)
J/A+A/625/A76 : NGC1052-DF2 VLT/MUSE datacubes (Emsellem+, 2019)
Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 9 F9.5 deg RAdeg Right Ascension of center (J2000)
10- 18 F9.5 deg DEdeg Declination of center (J2000)
20- 23 I4 --- Nx Number of pixels along X-axis
25- 28 I4 --- Ny Number of pixels along Y-axis
30- 39 A10 "datime" Obs.date Observation date
41- 48 F8.5 GHz Freq Observed frequency
50- 53 I4 Kibyte size Size of FITS file
55- 71 A17 --- FileName Name of FITS file, in subdirectory fits
73-107 A35 --- Title Title of the FITS file
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Acknowledgements:
Anne-Kathrin Baczko, baczko(at)mpifr-bonn.mpg.de
(End) Patricia Vannier [CDS] 23-Nov-2021