Detection of diffuse radio emission in the galaxy clusters A800, A910,
  A1550, and CL1446+26
  Radio halos are elusive sources located at the center of merging galaxy
clusters. To date, only about 40 radio halos are known, thus the discovery of
new halos provide important insights on this class of sources. To improve the
statistics of radio halos, we investigated the radio continuum emission in a
sample of galaxy clusters. We analyzed archival Very Large Array observations
at 1.4 GHz, with a resolution of about 1 arcmin. These observations
complemented by X-ray, optical, and higher resolution radio data allowed to
detect a new radio halo in the central region of A800 and A1550. We discovered
a radio relic in the periphery of A910, and finally we revealed both a halo and
a relic in CL1446+26.Clusters hosting these new halos show an offset between
the radio and the X-ray peak. By analyzing this offset statistically we found
that radio halos can be quite asymmetric with respect to the X-ray gas
distribution, with an average radio - X-ray displacement of about 180 kpc. When
the offsets are normalized by the halo size, there is a tendency for smaller
halos to show larger displacements.
