Using JADES NIRCam photometry to investigate the dependence of stellar mass inferences on the IMF in the early universe

Abstract

The James Webb Space Telescope (JWST) has enabled the study of the infant universe in unprecedented detail with the hope of revealing how the first galaxies formed and subsequently evolved. If these data were interpreted in the framework of star formation processes in the Milky Way, JWST observations likely contradict cold dark matter theory predictions and would force a reassessment of basic physics. Using a sample of distant galaxies with high-quality photometry and spectroscopically confirmed distances, we investigate how changing star formation parameters avoids such a contradiction with galaxy age and stellar mass being traded against each other to match observed galaxy properties. The cold dark matter paradigm remains consistent with observations. The detection of numerous and relatively bright galaxies at redshifts z > 9 has prompted new investigations into the star-forming properties of high-redshift galaxies. Using local forms of the initial mass function (IMF) to estimate stellar masses of these galaxies from their light output leads to galaxy masses that are at the limit allowed for the state of the Lambda Cold Dark Matter (?CDM) Universe at their redshift. We explore how varying the IMF assumed in studies of galaxies in the early universe changes the inferred values for the stellar masses of these galaxies. We infer galaxy properties with the spectral energy distribution (SED) fitting code Prospector using varying IMF parameterizations for a sample of 102 galaxies with photometry from the James Webb Space Telescope, JWST Advanced Deep Extragalactic Survey that are spectroscopically confirmed to be at z>6.7, with additional photometry from the JWST Extragalactic Medium Band Survey for twenty-one of the galaxies. We demonstrate that models with stellar masses reduced by a factor of three or more do not affect the modeled SED.