A precise and accurate determination of the cosmic microwave background temperature at z = 0.89
Journal article, 2013
Context. According to the Big Bang theory and as a consequence of adiabatic expansion of the Universe, the temperature of the cosmic microwave background (CMB) increases linearly with redshift. This relation is, however, poorly explored, and detection of any deviation would directly lead to (astro-)physics beyond the standard model.
Aims. We aim to measure the temperature of the CMB with an accuracy of a few percent at z = 0.89 toward the molecular absorber in the galaxy lensing the quasar PKS 1830−211.
Methods. We adopted a Monte-Carlo Markov chain approach, coupled with predictions from the non-LTE radiative transfer code RADEX, to solve the excitation conditions of a set of various molecular species directly from their spectra.
Results. We determine TCMB = 5.08 ± 0.10 K at 68% confidence level. Our measurement is consistent with the value TCMB = 5.14 K predicted by the standard cosmological model with adiabatic expansion of the Universe. This is the most precise determination of TCMB at z > 0 to date.
cosmology: observations / cosmic background radiation / cosmological parameters / quasars: absorption lines / quasars: individual: PKS 1830 / 211
Author
Sebastien Muller
Chalmers, Earth and Space Sciences, Onsala Space Observatory
A. Beelen
University of Paris-Sud
John H Black
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
S.J. Curran
ARC Centre of Excellence for All-sky Astrophysics (CAASTRO)
The University of Sydney
Cathy Horellou
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
Susanne Aalto
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
F. Combes
Centre national de la recherche scientifique (CNRS)
M. Guélin
Institut de Radioastronomie Millimétrique (IRAM)
Ecole Normale Superieure (ENS)
C. Henkel
King Abdulaziz University
Max Planck Society
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 551 A109 (pp. 1-13) A109Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
Infrastructure
Onsala Space Observatory
DOI
10.1051/0004-6361/201220613