27 research outputs found
A plethora of diffuse steep spectrum radio sources in Abell 2034 revealed by LOFAR
With Low-Frequency Array (LOFAR) observations, we have discovered a diverse
assembly of steep spectrum emission that is apparently associated with the
intra cluster medium (ICM) of the merging galaxy cluster Abell 2034. Such a
rich variety of complex emission associated with the ICM has been observed in
few other clusters. This not only indicates that Abell 2034 is a more
interesting and complex system than previously thought but it also demonstrates
the importance of sensitive and high-resolution, low-frequency observations.
These observations can reveal emission from relativistic particles which have
been accelerated to sufficient energy to produce observable emission or have
had their high energy maintained by mechanisms in the ICM. The most prominent
feature in our maps is a bright bulb of emission connected to two steep
spectrum filamentary structures, the longest of which extends perpendicular to
the merger axis for 0.5Mpc across the south of the cluster. The origin of these
objects is unclear, with no shock detected in the X-ray images and no obvious
connection with cluster galaxies or AGNs. We also find that the X-ray bright
region of the cluster coincides with a giant radio halo with an irregular
morphology and a very steep spectrum. In addition, the cluster hosts up to
three possible radio relics, which are misaligned with the cluster X-ray
emission. Finally, we have identified multiple regions of emission with a very
steep spectral index that seem to be associated with either tailed radio
galaxies or a shock.Comment: 15 pages, 9 figures, 1 table, accepted for publication in MNRA