Low frequencies and interplanetary scintillation: Peaked-spectrum sources at high-redshift?
Many active galactic nuclei (AGN) show a spectral peak in their radio spectra. Peaked-spectrum radio sources (including gigahertz-peaked spectrum and compact steep spectrum sources) are radio galaxies that often display small angular extents, suggesting that they are either very young AGN or are confined by a dense surrounding medium. We here present a spectacular sample of 1484 low-frequency peaked-spectrum sources derived from the Murchison Widefield Array's GLEAM survey; for 95% of this sample, the peaked spectral behaviour is newly identified. We will also discuss the use of interplanetary scintillation to constrain the arcsecond scale of many of these sources at 150 MHz, exploring the possibility that the combination of an observed MHz peak and small radio structure at 150 MHz are good identifiers to find radio sources at redshifts greater than 5.