Ly$\alpha$ halos and UV continuum morphologies of Tadpole Galaxies at $z>3$

Abstract

Tadpole and clump-chain galaxies are a morphologically distinct population among high-redshift star-forming galaxies whose disturbed structures may influence the escape and propagation of Ly$\alpha$ photons. We investigate the Ly$\alpha$ and UV continuum properties of 12 tadpole galaxies in the redshift range of z $\sim$ 3 -- 5.5 identified in the Hubble Ultra Deep Field (HUDF) using deep MUSE observations. Accounting for their elongated morphologies, we construct surface brightness profiles and characterize the spatial extent of their Ly$\alpha$ emission. Extended Ly$\alpha$ halos are detected in 10 of the 12 galaxies, demonstrating that diffuse Ly$\alpha$ emission is common among tadpole systems. Approximately 40\% of the sample exhibits double-peaked Ly$\alpha$ profiles. While the effective radii (${\mathrm{R}}_{\mathrm{e}}$) of the Ly$\alpha$ emission generally follow the spatial extent of the UV continuum, the Ly$\alpha$ halos are typically more symmetric and often exhibit spatial offsets from the stellar component. Some galaxies also display asymmetric and outflow-like Ly$\alpha$ structures suggestive of anisotropic escape and complex radiative transfer effects. Together, these results suggest that the disturbed morphologies of tadpole galaxies may influence the transport of Ly$\alpha$ photons and contribute to the formation of extended Ly$\alpha$ halos in the circumgalactic medium.

16 pages, 7 figures, 1 table, comments are welcome