Radio-detected Lyα emitters at 1.88 < z < 3.52: AGN fraction and Lyα emission

Lyα emitters (LAEs) are galaxies with strong Lyα emission, tracing early star formation and ionizing radiation. Their connection to active galactic nuclei (AGNs) is key to understanding the mechanisms behind (extended) Lyα emission. For this study, we measured the fraction of LAEs identified as radio-emitting AGNs (f_ AGN, radio ) and the fraction of radio sources that exhibit Lyα emission (f_ Ly α ) to investigate the connection of radio AGN activity to Lyα emission at 1.88 < z < 3.52. We identified sources that were detected in both the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) and the LOw Frequency ARray (LOFAR) surveys. These matches were drawn from spectroscopically confirmed LAEs and radio sources. After applying completeness corrections, we obtain f_ AGN, radio = = erg s and f_ Ly α (for Lyα fluxes above 3 10^ -17 -1 $ cm^-2 and radio flux densities above 0.1 mJy at 144 MHz). The fraction f_ AGN,radio increases from 0.4 L_ % at log_ 10 Lyα, erg -1 ≈ 42.6 to 9.7 L_ % at log_ 10 Lyα, erg -1 ≈ 44.5. The fraction f_ Lyα rises from 0.7 L_ at log_ 10 150,̊m W -1 ≈ 24.6 to 55.8 ≈ 28.3. `LAEs with radio AGNs' and `optical AGNs with Lyα emission' exhibit similar radio luminosity distributions above the AGN threshold (L_ % for $ L_ 10 150,̊m W -1 150, MHz > 10^ 23.9 W Hz -1 ), though optical AGNs show systematically higher Lyα luminosities. We find no statistically significant correlations of Lyα luminosity with both radio luminosity and a low-frequency spectral index, suggesting that Lyα emission is regulated by gas properties rather than jet power alone. We also find a positive correlation between the full width at half maximum (FWHM) and luminosity of the Lyα line, suggesting that more luminous sources have broader lines, potentially due to enhanced outflows or velocity dispersions. However, we find no correlation between FWHM and radio size, indicating minimal direct jet-gas interaction in these systems. Our results show that most Lyα emission at 1.88<z<3.52 is powered by star formation, with radio AGN activity confined to a small luminous subset ( While luminous systems preferentially host radio AGNs, the lack of correlation between Lyα and radio luminosities in individual sources indicates that Lyα emission is governed primarily by host galaxy gas properties rather than direct AGN jet coupling.