| Abstract: Post-starburst (PSB) galaxies exhibit strong Balmer absorption lines and weak or absent nebular emission lines, indicating a recent, intense starburst that ended about 100–300 Myr ago. We carried out a study of radio emission from 104 PSB galaxies in the redshift range 0.03–0.4 using 144 MHz LOFAR LoTSS2 and 1.4 GHz VLA FIRST imaging. Although only about ∼2% of the sample is detected at 1.4 GHz, this detection rate rises to 8.4% at 144 MHz, highlighting the enhanced sensitivity of low-frequency radio observations to faint radio sources. We find that PSBs exhibit systematically flatter radio spectral indices (got α= -0.34 between 144 MHz and 1.4 GHz) compared to typical star-forming galaxies (α= -0.55), and also show significantly reduced radio luminosity in the standard radio–far-infrared correlation (L144MHz–L60 µm plane). For a subset of this PSB galaxies sample, we also conducted follow-up radio observations at intermediate frequencies with uGMRT (Band 4 and Band 5) and at higher frequencies (S, C,X Band) with the JVLA. Detailed modeling of PSB’s multi-frequency radio spectral energy distributions (spanning 144 MHz to 1.4 GHz), together with estimates of the emission measure and high-angular-resolution nuclear morphologies from the VLA data, will be presented. The observed spectral flattening interpreted as free–free absorption by ionized gas along the line of sight. By combining our radio results with optical line-diagnostics, we infer that PSB galaxies often host low-luminosity AGN, which can coexist with ongoing star-formation which is dust-obscured. Our study emphasizes the crucial role of radio observations of PSB galaxies in tracing the evolutionary pathways of star-forming systems, probing the link between AGN activity and Star formation, and uncovering residual star formation hidden by dust in PSB galaxies. |
