Murchison Widefield Array detection of steep-spectrum, diffuse,
  non-thermal radio emission within Abell 1127
  Diffuse, non-thermal emission in galaxy clusters is increasingly being
detected in low-frequency radio surveys and images. We present a new diffuse,
steep-spectrum, non-thermal radio source within the cluster Abell 1127 found in
survey data from the Murchison Widefield Array (MWA). We perform follow-up
observations with the 'extended' configuration MWA Phase II with improved
resolution to better resolve the source and measure its low-frequency spectral
properties. We use archival Very Large Array S-band data to remove the discrete
source contribution from the MWA data, and from a power law model fit we find a
spectral index of $-1.83\pm0.29$ broadly consistent with relic-type sources.
The source is revealed by the Giant Metrewave Radio Telescope (GMRT) at 150 MHz
to have an elongated morphology, with a projected linear size of 850 kpc as
measured in the MWA data. Using Chandra observations we derive morphological
estimators and confirm quantitatively that the cluster is in a disturbed
dynamical state, consistent with the majority of phoenices and relics being
hosted by merging clusters. We discuss the implications of relying on
morphology and low-resolution imaging alone for the classification of such
sources and highlight the usefulness of the MHz to GHz radio spectrum in
classifying these types of emission. Finally, we discuss the benefits and
limitations of using the MWA Phase II in conjunction with other instruments for
detailed studies of diffuse, steep-spectrum, non-thermal radio emission within
galaxy clusters.
