Physical origin and observational bias of high-redshift galaxy clumpiness

Determine the physical origin of irregular and clumpy structures in high-redshift galaxies and quantify the extent to which observational biases shape their apparent morphologies.

Background

The paper investigates the clumpiness of high-redshift galaxies using power spectra of stellar-mass distributions and mock Hα, far-ultraviolet, and optical emission maps from the thesan-zoom radiation-hydrodynamic simulations. Its results indicate that stellar-mass distributions are generally smooth, whereas tracers of recent star formation exhibit pronounced small-scale structure, and that apparent clumpiness varies with stellar feedback, star-formation phase, wavelength, point-spread-function effects, and noise.

Despite these findings, the authors explicitly identify the physical origin of the observed clumpy structures and the role of observational selection and measurement biases as unresolved issues. Clarifying these issues is necessary for interpreting JWST morphologies and for using galaxy clumpiness to constrain high-redshift galaxy-formation physics.