We present Very Long Baseline Interferometry observations of a faint and low-luminosity ( L _ { 1.4 GHz } < 10 ^ { 27 } W Hz ^ { -1 } ) Gigahertz-Peaked Spectrum ( GPS ) and Compact Steep Spectrum ( CSS ) sample .
We select eight sources from deep radio observations that have radio spectra characteristic of a GPS or CSS source and an angular size of \theta \lesssim 2 \arcsec , and detect six of them with the Australian Long Baseline Array .
We determine their linear sizes , and model their radio spectra using Synchrotron Self Absorption ( SSA ) and Free Free Absorption ( FFA ) models .
We derive statistical model ages , based on a fitted scaling relation , and spectral ages , based on the radio spectrum , which are generally consistent with the hypothesis that GPS and CSS sources are young and evolving .
We resolve the morphology of one CSS source with a radio luminosity of 10 ^ { 25 } ~ { } \mbox { W Hz } ^ { -1 } , and find what appear to be two hotspots spanning 1.7 kpc .
We find that our sources follow the turnover-linear size relation , and that both homogenous SSA and an inhomogeneous FFA model can account for the spectra with observable turnovers .
All but one of the FFA models do not require a spectral break to account for the radio spectrum , while all but one of the alternative SSA and power law models do require a spectral break to account for the radio spectrum .
We conclude that our low-luminosity sample is similar to brighter samples in terms of their spectral shape , turnover frequencies , linear sizes , and ages , but can not test for a difference in morphology .