Measuring neutrino masses with joint JWST and DESI DR2 data

Abstract

Early JWST observations reveal an unexpectedly abundant population of high-redshift candidate massive galaxies at $z \gtrsim 7$, and recent DESI measurements show a preference for dynamical dark energy, which together present a significant challenge to the standard $Λ$CDM cosmology. In this work, we jointly analyze high-redshift galaxy data from JWST, baryon acoustic oscillations data from DESI DR2, and cosmic microwave background (CMB) data from Planck and ACT, measuring the total neutrino mass $\sum m_ν$. We consider three dark energy models ($Λ$CDM, $w$CDM, and $w_0w_a$CDM) and three mass hierarchies. Our results indicate that in the $w_0w_a$CDM model, adding JWST data to CMB+DESI tightens the upper limit of $\sum m_ν$ by about $5.8\%-10.2\%$, and we obtain $\sum m_ν < 0.167~\mathrm{eV}$ ($2σ$) in the normal hierarchy (NH) case. Furthermore, JWST also offers indicative lower limits on star formation efficiency parameter of $f_{*,10} \gtrsim 0.146-0.161$. Bayesian evidence weakly favors the $w_0w_a$CDM+$\sum m_ν$(NH) model relative to the $Λ$CDM+$\sum m_ν$(NH) model using CMB+DESI+JWST data. These results suggest that the joint analysis of high-redshift JWST data and low-redshift DESI data provides compelling constraints on neutrino mass and merits further investigation.

Figures (3)

• Figure 1: The one-dimensional marginalized posterior distributions of $\sum m_{\nu}$ for the $\Lambda\mathrm{CDM}+\sum m_{\nu}$, $w\mathrm{CDM}+\sum m_{\nu}$, and $w_{0}w_{a}\mathrm{CDM}+\sum m_{\nu}$ models, based on the CMB, DESI, and JWST data.
• Figure 2: Constraints on cosmological parameters in the $w_{0}w_{a}\mathrm{CDM}+\sum m_{\nu}$ (NH) model, using the CMB+DESI (green) and CMB+DESI+JWST (blue) datasets. The overlaid colored scatter points indicate the SFE parameter values, which are shown only for the CMB+DESI+JWST data.
• Figure 3: The Bayes factors, $\ln \mathcal{B}_{ij}$, for three cosmological models, $\Lambda{\rm CDM}+\sum m_{\nu}$, $w{\rm CDM}+\sum m_{\nu}$, and $w_0w_a{\rm CDM}+\sum m_{\nu}$, derived from JWST, DESI, and CMB data. Filled circles and triangles represent the NH and IH cases, respectively. The background gradient illustrates the Jeffreys scale, with progressively deeper tones corresponding to stronger evidence. In summary, for each data combination, more positive values of $\ln \mathcal{B}_{ij}$ indicate that the model is more strongly favored by the data, whereas more negative values indicate that it is disfavored.