Issue |
A&A
Volume 690, October 2024
|
|
---|---|---|
Article Number | A329 | |
Number of page(s) | 22 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361/202451515 | |
Published online | 22 October 2024 |
Ageing and dynamics of the tailed radio galaxies in Abell 2142
1
Dipartimento di Fisica e Astronomia (DIFA), Università di Bologna (UNIBO),
via Gobetti 93/2,
40129
Bologna,
Italy
2
Istituto Nazionale di Astrofisica (INAF) – Istituto di Radioastronomia (IRA),
via Gobetti 101,
40129
Bologna,
Italy
3
Istituto Nazionale di Astrofisica (INAF) – Osservatorio di Astrofisica e Scienza dello Spazio (OAS) di Bologna,
Via P. Gobetti 93/3,
40129
Bologna,
Italy
4
Center for Radio Astronomy Techniques and Technologies, Rhodes University,
Grahamstown
6140,
South Africa
5
Istituto Nazionale di Astrofisica (INAF) – Osservatorio Astronomico di Padova (OAPD),
Vicolo dell’Osservatorio 5,
35122
Padova,
Italy
6
Istituto Nazionale di Astrofisica (INAF) – Istituto di Astrofisica Spaziale e Fisica cosmica (IASF) di Milano,
Via A. Corti 12,
20133
Milano,
Italy
7
Minnesota Institute for Astrophysics, University of Minnesota,
116 Church St SE,
Minneapolis,
MN
55455,
USA
8
Leiden Observatory, Leiden University,
PO Box 9513,
2300
RA
Leiden,
The Netherlands
9
ASTRON, Netherlands Institute for Radio Astronomy,
Oude Hoogeveensedijk 4,
7991
PD,
Dwingeloo,
The Netherlands
10
Tata Institute of Fundamental Research,
Post Box 3, Ganeshkhind PO,
Pune
411007,
India
★ Corresponding author; luca.bruno4@unibo.it
Received:
15
July
2024
Accepted:
5
September
2024
Context. Tailed radio galaxies are shaped by ram pressure that is due 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 novel evidence of re-energising mechanisms that are nonetheless unclear.
Aims. 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.
Methods. We combined data from LOw Frequency Array (LOFAR), upgraded Giant Metrewave Radio Telescope (uGMRT), Very Large Array (VLA), and MeerKAT (from 30 MHz to 6.5 GHz) to carry out a detailed spectral analysis of T1 and T2. We analysed the surface brightness profiles, measured integrated and spatially resolved spectral indices. We performed a comparison with single injection ageing models. The Chandra X-ray data were used to search for discontinuities in the ICM properties in the direction of the targets.
Results. The spectral properties of T1 at low frequencies can be predicted by ageing models and provide constraints on the 3D dynamics of the host by assuming a constant velocity. However, a more complex scenario is suggested by the sharp transitions along sub-regions of the tail, local surface brightness enhancements, and a spectral shape at high frequencies that is not predicted by any of the models. This scenario may plausibly involve hydrodynamical instabilities and particle mixing. T2 exhibits unusual morphological and surface brightness features, and its spectral behaviour is not predicted by standard models. The effects of two active galactic nucleus (AGN) outburst events during the infall of T2 towards the cluster centre could potentially explain its characteristic properties.
Key words: radiation mechanisms: non-thermal / galaxies: clusters: intracluster medium / radio continuum: galaxies / galaxies: clusters: individual: Abell 2142
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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