J/A+A/682/A105 Bridges between galaxy clusters images (Pignataro+, 2024)
Probing diffuse radio emission in bridges between galaxy clusters with uGMRT.
Pignataro G.V., Bonafede A., Bernardi G., Riseley C.J., Dallacasa D.,
Venturi T.
<Astron. Astrophys. 682, A105 (2024)>
=2024A&A...682A.105P 2024A&A...682A.105P (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, galaxy ; Galaxies, interacting ; Radio sources
Keywords: radiation mechanisms: non-thermal - galaxies: clusters: general -
large-scale structure of Universe - radio continuum: general
Abstract:
The main purpose of this work is to investigate the properties of the
non-thermal emission in the interacting clusters pairs
Abell 0399-Abell 0401 and Abell 21-PSZ2 G114.9, found in an
interacting state. In both cases their connection along a filament is
supported by SZ effect detected by the Planck satellite and, in the
special case of Abell 0399-Abell 0401, the presence of a radio bridge
has been already confirmed by LOFAR observations at 140MHz. Here, we
analyse new high sensitivity wideband (250-500MHz) uGMRT data of these
two systems and describe an injection procedure to place limits on the
spectrum of Abell 0399-Abell 0401 and on the radio emission between
Abell 21-PSZ2 G114.9. For the A399-A401 pair, we are able to constrain
the steep spectral index of the bridge emission to be alpha>2.2 with a
95% confidence level between 140MHz and 400MHz. For the A21-PSZ2
G114.9 pair, we are able to place an upper limit on the flux density
of the bridge emission with two different methods, finding at the
central frequency of 383MHz a conservative value of fu1<260mJy at
95% confidence level, and a lower value of fu2<125mJy at 80%
confidence level, based on visual inspection and a morphological
criterion. Our work provides a constraint on the spectrum in the
bridge A399-A401 which disfavours shock-acceleration as the main
mechanism for the radio emission.
Description:
Observations of A399-A401 and A21-G114.9 were carried out with the
upgraded GMRT (uGMRT) in Band 3 (proposal code: 36_043, P.I.:
Bernardi). The total length of the observation was ten hours per pair,
including the time spent on calibration sources. Each cluster pair was
observed with two distinct pointings, one centred on each galaxy
cluster. This results in approximately four hours of on-source time
for each target galaxy cluster, and approximately one hour in total
spent on calibrators.
Objects:
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RA (2000) DE Designation(s)
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02 57 56.40 +13 00 58.9 Abell 0399 = PSZ1 G164.31-39.43
02 58 56.89 +13 34 56.0 Abell 0401 = PSZ2 G164.18-38.88
00 20 38.74 +28 41 40.4 A21 = ACO 21
00 21 24.61 +28 03 01.5 PSZ2 G114.9 = PSZ2 G114.90-34.35
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 155 4 List of fits images
fits/* . 4 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- 55 A26 "datime" Obs.date Observation date
57- 62 I6 Kibyte size Size of FITS file
64-102 A39 --- FileName Name of FITS file, in subdirectory fits
104-155 A52 --- Title Title of the FITS file
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Acknowledgements:
Giada Pignataro, giada.pignataro(at)studio.unibo.it
(End) Patricia Vannier [CDS] 20-Nov-2023