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Abstract The presence (and nature) of variations in the stellar initial mass function (IMF) at substantially subsolar masses and metallicities ( m 15,000 stars down to 0.16 M ⊙ within a single pointing of NIRCam on board JWST, using an observing strategy that minimizes contamination from point-source-like background galaxies. We explore three different functional forms of the IMF, forward modeling observed color–magnitude diagrams and luminosity functions. We find a best-fit single power law IMF slope of α = −1.61 − 0.03 + 0.03 , consistent with UFDs probed down to similar limiting masses. Fitting a broken power-law IMF, we find low- and high-mass slopes of α 1 = −1.44 − 0.04 + 0.04 and α 2 = −2.17 − 0.11 + 0.11 , respectively, consistent with solar neighborhood values. Assuming a lognormal IMF, we find a characteristic mass and lognormal width of m c = 0.1 2 − 0.03 + 0.03 M ⊙ and σ = 0.61 − 0.06 + 0.07 M ⊙ , respectively, allowing for characteristic masses lower than local values as seen in some simulations as well as low-metallicity Galactic clusters. Lastly, we quantify the impact of assumptions required in our analysis and discuss potential future improvements.
Cohen et al. (Thu,) studied this question.