The Physical Nature of Rest‐UV Galaxy Morphology during the Peak Epoch of Galaxy Formation

Motivated by the irregular and little-understood morphologies of z ~ 2 - 3galaxies, we use non-parametric coefficents to quantify the morphologies of 216galaxies which have been spectroscopically confirmed to lie at redshifts z =1.8 - 3.4 in the GOODS-N field. Using measurements of ultraviolet (UV) andoptical spectral lines, multi-band photometric data, and stellar populationmodels we statistically assess possible correlations between galaxy morphologyand physical observables such as stellar mass, star formation rate, and thestrength of galaxy-scale outflows. We find evidence that dustier galaxies havemore nebulous UV morphologies and that larger, more luminous galaxies may drivestronger outflows, but otherwise conclude that UV morphology is eitherstatistically decoupled from the majority of physical observables or determinedby too complex a combination of physical processes to provide characterizationswith predictive power. Given the absence of strong correlations between UVmorphology and physical parameters such as star formation rates, we aretherefore unable to support the hypothesis that morphologically irregulargalaxies predominantly represent major galaxy mergers. Comparing galaxysamples, we find that IR-selected BzK galaxies and radio-selected submillimetergalaxies (SMGs) have UV morphologies similar to the optically selected sample,while distant red galaxies (DRGs) are more nebulous.