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arXiv · 2605.11101

Tracing Radio AGN-Driven Quenching in Post-Starburst Galaxies at Cosmic Noon

Pallavi Patil·Kate Rowlands·Katherine Alatalo·Omar Almaini·Vivienne Wild·David Maltby·Rob J. Ivison·Vinod Arumugam·K. Decker French·Timothy Heckman·Mark Lacy·Yuanze Luo·Kristina Nyland·Justin Atsushi Otter·Andreea Petric·Namrata Roy·Maya Skarbinski
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Abstract

We present a radio continuum study of photometrically selected cosmic noon (0.5 10^{11}$M$_\odot$. Massive PSBs have a comparable detection fraction to that of massive quiescent galaxies ($f_{det}=8\pm1\%$), and both classes have lower fractions than that of massive star-forming galaxies ($f_{det}=13\pm1\%$) in the same field. The radio luminosities of detected PSBs, ${\rm L}_{1.4}\sim 10^{22.8}-10^{24.9}$W/Hz, exceed those from star formation by a median factor of 37 indicative of a possible AGN origin. Their compact morphologies ($\lesssim15$ kpc at $z_{med}=1.5$) suggest low-luminosity AGN with less powerful jets. Stacking the undetected PSBs reveals a weak radio detection ($3.9\sigma$) in the highest mass bin (M$_*>10^{11}$M$_\odot$). In contrast, 1.4 GHz detected quiescent galaxies have radio luminosities reaching radio-loud levels, and a higher prevalence of extended morphologies indicative of large-scale jetted AGN. The AGN contribution is also detected in stacked measurements of quiescent galaxies. Overall, our results support a short radio AGN duty cycle for PSBs, characterized by weak radio jets, suggesting radio-driven maintenance mode feedback may become important at older ages.

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Pallavi Patil, Kate Rowlands, Katherine Alatalo, Omar Almaini, Vivienne Wild, David Maltby, Rob J. Ivison, Vinod Arumugam, K. Decker French, Timothy Heckman, Mark Lacy, Yuanze Luo, Kristina Nyland, Justin Atsushi Otter, Andreea Petric, Namrata Roy, Maya Skarbinski. 2026-05-11. Tracing Radio AGN-Driven Quenching in Post-Starburst Galaxies at Cosmic Noon. https://doi.org/10.3847/1538-4357%2Fae70ef

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