J/A+A/659/A20 2A0335+096 LOFAR images (Ignesti+, 2022)
A LOFAR view into the stormy environment of the galaxy cluster 2A0335+096.
Ignesti A., Brunetti G., Shimwell T., Gitti M., Birzan L., Botteon A.,
Brueggen M., de Gasperin F., Di Gennaro G., Edge A.C., Riseley C.J.,
Roettgering H.J.A., van Weeren R.J.
<Astron. Astrophys. 659, A20 (2022)>
=2022A&A...659A..20I 2022A&A...659A..20I (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Radio sources
Keywords: radio continuum: galaxies - galaxies: clusters: intracluster medium -
methods: observational - galaxies: clusters: individual: 2A0335+096 -
X-rays: galaxies: clusters
Abstract:
Radio observations represent a powerful probe of the physics occurring
in the intracluster medium (ICM) because they trace the relativistic
cosmic rays in the cluster magnetic fields, or within galaxies
themselves. By probing the low-energy cosmic rays, low-frequency radio
observations are especially interesting because they unveil emission
powered by low-efficiency particle acceleration processes, which are
believed to play a crucial role in the origin of diffuse radio
emission.
We investigate the origin of the radio mini-halo at the center of the
galaxy cluster 2A0335+096 and its connection to the central galaxy and
the sloshing cool core. We also study the properties of the head-tail
galaxy GB6 B0335+096 hosted in the cluster to explore the lifecycle of
the relativistic electrons in its radio tails.
We use new LOw Frequency ARray (LOFAR) observations from the LOFAR
Two-meter Sky Survey at 144MHz to map the low-frequency emission with
a high level of detail. The new data were combined with archival Giant
Metrewave Radio Telescope and Chandra observations to carry out a
multi-wavelength study.
We have made the first measurement of the spectral index of the
mini-halo (α=-1.2±0.1 between 144MHz and 1.4GHz) and the lobes
of the central source (α≃-1.5±0.1 between 144 and 610MHz).
Based on the low-frequency radio emission morphology with respect to
the thermal ICM, we propose that the origin of the diffuse radio
emission is linked to the sloshing of the cool core. The new data
revealed the presence of a Mpc-long radio tail associated with GB6
B0335+096. The observed projected length is a factor 3 longer than the
expected cooling length, with evidence of flattening in the spectral
index trend along the tail. Therefore, we suggest that the electrons
toward the end of the tail are kept alive by the ICM gentle
re-acceleration.
Description:
We produced new images of the 2A 0335+096 galaxy cluster with LOFAR at
144MHz.
Objects:
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RA (2000) DE Designation(s)
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03 38 35.3 +09 57 54 2A 0335+096 = ZwCl 0335+0956
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 145 3 List of fits images
fits/* . 3 Individual fits images
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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- 58 F7.3 MHz Freq Observed frequency
60- 64 I5 Kibyte size Size of FITS file
66-122 A57 --- FileName Name of FITS file, in subdirectory fits
124-145 A22 --- Title Title of the FITS file
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Acknowledgements:
Alessandro Ignesti, alessandro.ignesti(at)inaf.it
(End) Patricia Vannier [CDS] 22-Feb-2022