Cosmological impact of microwave background temperature measurements

TL;DR

Measuring the cosmic microwave background temperature across redshifts provides a powerful new way to test and constrain cosmological models, rivaling traditional methods like supernovae and Hubble measurements.

Contribution

This paper demonstrates that temperature measurements of the microwave background can now effectively constrain cosmological models, including those explaining universe acceleration, with comparable power to established probes.

Findings

Temperature data constrains cosmological parameters effectively.

Combination of temperature and other data improves model constraints.

Temperature data rules out some alternative cosmological models.

Abstract

The cosmic microwave background temperature is a cornerstone astrophysical observable. Its present value is tightly constrained, but its redshift dependence, which can now be determined until redshift $z\sim6.34$, is also an important probe of fundamental cosmology. We show that its constraining power is now comparable to that of other background cosmology probes, including Type Ia supernovae and Hubble parameter measurements. We illustrate this with three models, each based on a different conceptual paradigm, which aim to explain the recent acceleration of the universe. We find that for parametric extension of $\Lambda$CDM the combination of temperature and cosmological data significantly improves constraints on the model parameters, while for alternative models without a $\Lambda$CDM limit this data combination rules them out.