J/A+A/690/A329 Abell 2142 radio images (Bruno+, 2024)
Ageing and dynamics of the tailed radio galaxies in Abell 2142.
Bruno L., Venturi T., Dallacasa D., Brienza M., Ignesti A., Brunetti G.,
Riseley C.J., Rossetti M., Gastaldello F., Botteon A., Rudnick L.,
van Weeren R.J., Shulevski A., Lal D.V.
<Astron. Astrophys. 690, A329 (2024)>
=2024A&A...690A.329B 2024A&A...690A.329B (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Radio continuum
Keywords: radiation mechanisms: non-thermal -
galaxies: clusters: intracluster medium - radio continuum: galaxies -
galaxies: clusters: individual: Abell 2142
Abstract:
Tailed radio galaxies are shaped by ram pressure owing to the
high-velocity motion of their host through the intracluster medium
(ICM). Recent works have reported on the increasing complexity of the
phenomenology of tailed galaxies, with departures from theoretical
ageing models and evidence of re-energising mechanisms, which are yet
unclear.
The nearby (z=0.0894) galaxy cluster Abell 2142 hosts two tailed
galaxies, namely T1 and T2, which exhibit peculiar morphological
features. We aim to investigate the properties of T1 and T2 and
constrain their spectral evolution, dynamics, and interactions with
the ICM.
We combined LOw Frequency Array (LOFAR), upgraded Giant Metrewave
Radio Telescope (uGMRT), Very Large Array (VLA), and MeerKAT data
(from 30MHz to 6.5GHz) to carry out a detailed spectral analysis of
T1 and T2. We analysed surface brightness profiles, measured
integrated and spatially-resolved spectral indices, and performed a
comparison with single injection ageing models. Chandra X-ray data
were used to search for discontinuities in the ICM properties in the
direction of the targets.
The spectral properties of T1 at low frequencies are predicted by
ageing models, and provide constraints on the 3D dynamics of the host
by assuming a constant velocity. However, sharp transitions along
sub-regions of the tail, local surface brightness enhancements,
and a spectral shape at high frequencies that is not predicted by
models suggest a more complex scenario, possibly involving
hydrodynamical instabilities and particle mixing. T2 exhibits unusual
morphological and surface brightness features, and its spectral
behaviour is not predicted by standard models. Two AGN outburst events
during the infall of T2 towards the cluster centre could explain its
properties.
Description:
Radio images full resolution (Figs. 3, 4) in the paper.
LOFAR observed A2142 for 16 and 32 hours with the Low Band Antenna
(LBA) and High Band Antenna (HBA) arrays operating at 30-70MHz and
120-168MHz, respectively. The GMRT observed A2142 for 5 hours at
305-340MHz (see also Venturi et al., 2017A&A...603A.125V 2017A&A...603A.125V);
furthermore, 3-hour observations were carried out with the uGMRT at
300-500MHz (band 3). Mosaicked pointings (each having a field of view
of ∼30') on A2142 were obtained with the Very Large Array (VLA) at
1-2GHz (L-band) in C-array and D-array configurations, for a total of
2 hours. MeerKAT observed A2142 at 872-1712MHz (L-band) for 5.5 hours
as part of the 'MeerKAT-meets-LOFAR mini-halo census' project (Riseley
et al. 2022MNRAS.512.4210R 2022MNRAS.512.4210R, 2023MNRAS.524.6052R 2023MNRAS.524.6052R).
Objects:
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RA (2000) DE Designation(s)
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15 58 14.37 +27 12 57.7 Abell 2142 = ClG 1556.2+2722
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 132 10 List of fits images
fits/* . 10 Individual fits images
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See also:
J/A+A/686/A44 : MeerKAT L-band image of Abell 2142 (Riseley+, 2024)
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- 50 A21 "datime" Obs.date Observation date
52- 60 F9.4 MHz Freq Observed frequency
62- 66 I5 Kibyte size Size of FITS file
68- 93 A26 --- FileName Name of FITS file, in subdirectory fits
95-132 A38 --- Title Title of the FITS file
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Acknowledgements:
Luca Bruno, luca.bruno4(at)unibo.it
(End) Patricia Vannier [CDS] 09-Sep-2024