The study of extended radio galaxies in MERGHERS fields

We present a concise proceedings summary of our study of extended radio galaxies (ERGs) in the MeerKAT Exploration of Relics, Giant Halos, and Extragalactic Radio Sources (MERGHERS) Tier 1 field centred on ACT-CL J0438−5419 using MeerKAT L-band data at 1.28 GHz. Raw visibilities were processed with the oxkat pipeline through 1GC–3GC calibration and imaging, followed by primary-beam correction, astrometric checks, and sub-band imaging for in-band spectral index mapping. A cleaned catalogue of ERGs was assembled via PyBDSF and visual inspection. Cross-matching with RACS, SUMSS, and GLEAM-X provided broad-band fluxes; DECaLS and AllWISE enabled host identification and photometric redshifts. We report a morphology mix dominated by FRII sources, with FRI, WAT, HT, Z-shaped and unclassified sources also present. In-band spectral index maps show the expected steepening in outer lobes (𝛼 ≲ −0.5) and flatter spectra near cores, consistent with ongoing particle injection. We comment on environment for cluster vs field sources and outline future spectro-polarimetric extensions to the full MERGHERS sample.