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This study examines ultralight scalar-field dark matter within cosmologies that allow dark energy to change over time, rather than assuming it remains constant. Using data from cosmic microwave background observations, baryon acoustic oscillations, and supernovae, researchers found that scalar-field dark matter particles must have a mass above 10^-24 electron volts to be consistent with observations. The analysis shows that incorporating this alternative dark matter model does not significantly change conclusions about dark energy's evolution, including evidence for a "phantom crossing" where dark energy's properties shift at recent cosmic times.
Why it matters
This research helps narrow down the possible properties of dark matter and dark energy, the two mysterious components that together comprise roughly 95% of the universe's total energy content. By simultaneously constraining both components using multiple independent astronomical datasets, the study provides tighter limits on theoretical models attempting to explain the universe's accelerating expansion and the nature of its invisible mass.
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⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Abstract: We investigate the cosmological implications of scalar-field dark matter (SFDM) in a dynamical dark energy framework, extending previous analyses that considered SFDM within the standard $Lambda$CDM cosmological model. We consistently implement the scenario at both the background and linear perturbation levels. We perform Bayesian parameter inference using Planck CMB measurements, DESI DR2 baryon acoustic oscillation (BAO) data, and Pantheon+ Type Ia supernovae to constrain the model parameter space. Our theoretical predictions show that lighter scalar-field masses produce increasingly strong scale-dependent suppression of matter fluctuations and more pronounced modifications to the CMB temperature power spectrum, whereas heavier masses progressively approach the cold dark matter limit. For the SFDM mass, we obtain a one-sided 95% lower limit of $log_{10}(m_phi/{rm eV})>-24.04$ from our main joint analysis. We find that replacing the standard cold dark matter fluid with SFDM does not qualitatively alter the constraints on dynamical dark energy or the evidence for its evolution, including a phantom crossing at low redshifts.
Source: Constraining Ultralight Dark Matter in Dynamical Dark Energy Cosmologies