Radio morphology

Figure 2: VLA/CnB-array images (contours) of A4059/PKS 2354-35 taken at 4.7GHz (left panel) and 1.4GHz (right panel) overlaid on the 4-$\sigma$ adaptively smoothed X-ray image.

Our new radio maps are presented in Fig. 2 as contours of flux density overlaid on an adaptively smoothed 0.3-8.0keV ACIS image. It is interesting to compare this with the high-resolution 8.5GHz and 4.8GHz VLA/A- and B-array images of Taylor et al. (1994). While the radio emission at 8.5 GHz extends to the NW X-ray cavity and coincides with the deepest part of the cavity, it is not spatially coincide with the SE cavity (see Fig. 1 in Heinz et al. 2002). Our new CnB-array radio images show that the 1.4GHz emission also does not extend into the SE cavity. Indeed, the radio axis does not seem to be aligned with the axis joining two X-ray cavities and there is no evidence for bending of the radio structure toward the direction of the two cavities. Below, we discuss the possibility that the X-ray cavities correspond to old radio lobes which have been moved around by bulk ICM flows and may only be directly observable at low radio frequencies (100MHz and below).