Wide-band spectral variability of peaked spectrum sources

ABSTRACT Characterizing spectral variability of radio sources is a technique that offers the ability to determine astrophysics intervening media, source structure, emission, and absorption processes. We present broadband (0.072–10 GHz) 15 peaked-spectrum (PS) with Australia Telescope Compact Array (ATCA) Murchison Widefield (MWA). These PS were observed quasi-contemporaneously ATCA MWA four six times during 2020 approximately monthly cadence. Variability was not detected at 1–10 GHz frequencies but 13 targets show significant megahertz frequencies. conclude majority seen due refractive interstellar scintillation compact component ?25 mas across. also identify change in their shape Three these are consistent variable optical depth from an inhomogeneous free–free absorbing cloud around source. One ejection travelling along jet. as method for determining physical origins providing further evidence support models where modelling alone insufficient.