Callingham et al.
(2015) present broadband observations and spectral modeling of PKS B0008-421
and identify it as an extreme gigahertz-peaked spectrum (GPS) source.
PKS B0008-421 is characterized by the steepest known spectral slope below the
turnover, close to the theoretical limit of synchrotron
self-absorption, and the smallest known spectral width of any GPS source.
Spectral coverage of the source spans from 0.118 to 22 GHz, which includes
data from the Murchison Widefield Array (MWA) and the wide bandpass receivers
on the Australia Telescope Compact Array (ATCA). - The above image shows
PKS 0008-421 as detected in the GLEAM survey at 158 MHz overlaid onto the
spectral energy distribution (SED) from MWA and the ATCA.
