New JVLA observations at 3 GHz and 5.5 GHz of the `Kite' radio source in Abell 2626
Journal
Date Issued
2017
Author(s)
Abstract
We report on new JVLA observations performed at 3 GHz and 5.5 GHz of Abell
2626. The cluster has been the object of several studies in the recent years
due to its peculiar radio emission, which shows a complex system of symmetric
radio arcs characterized by a steep spectrum. The origin of these radio sources
is still unclear. Due to their mirror symmetry toward the center, it has been
proposed that they may be created by pairs of precessing jets powered by the
inner AGN. The new JVLA observations were requested with the specific aim of
detecting extended emission on frequencies higher than 1.4 GHz, in order to
constrain the jet-precession model by analyzing the spectral index and
radiative age patterns alongs the arcs. We performed a standard data reduction
of the JVLA datasets with the software CASA. By combining the new 3 GHz data
with the archival 1.4 GHz VLA dataset we produced a spectral index maps of the
extended emission, and then we estimated the radiative age of the arcs by
assuming that the plasma was accelerated in moving hot-spots tracing the arcs.
Thanks to the high sensitivity of the JVLA, we achieve the detection of the
arcs at 3 GHz and extended emission at 5.5 GHz. We measure a mean spectral
index <-2.5 for the arcs up to 3 GHz. No clear spectral index, or radiative
age, trend is detected across the arcs which may challenge the interpretation
based on precession or put strong constraints on the jet-precession period. In
particular, by analyzing the radiative age distribution along the arcs, we were
able to provide for the first time a time-scale < 26 Myr of the jet-precession
period.
Volume
604
Start page
A21
Issn Identifier
0004-6361
Rights
open.access
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