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Sub-percent constraints on cosmological temperature evolution

A. Avgoustidis, , G. Luzzi, C. J. A. P. Martins, R. T. Génova-Santos

Abstract
The redshift dependence of the cosmic microwave background temperature is one of the key cosmological observables. In the standard cosmological model one has T(z)=T0(1+z), where T0 is the present-day temperature. Deviations from this behavior would imply the presence of new physics. Here we discuss how the combination of all currently available direct and indirect measurements of T(z) constrains the common phenomenological parametrization T(z)=T0(1+z)1−β, and obtain the first sub-percent constraint on the β parameter, specifically β=(7.6±8.0)×10−3 at the 68.3% confidence level.

Physical Review D
Volume 93
February 2016

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Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

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