Volume 551, March 2013
|Number of page(s)||13|
|Section||Cosmology (including clusters of galaxies)|
|Published online||04 March 2013|
A precise and accurate determination of the cosmic microwave background temperature at z = 0.89
Department of Earth and Space SciencesChalmers University of Technology,
Onsala Space Observatory,
2 Institut d’Astrophysique Spatiale, Bât. 121, Université Paris-Sud, 91405 Orsay Cedex, France
3 Sydney Institute for Astronomy, School of Physics, The University of Sydney, 2006 NSW, Australia
4 ARC Centre of Excellence for All-sky Astrophysics (CAASTRO), Australia
5 Observatoire de Paris, LERMA, CNRS, 61 Av. de l’Observatoire, 75014 Paris, France
6 Institut de Radioastronomie Millimétrique, 300 rue de la piscine, 38406 Saint-Martin d’Hères, France
7 École Normale Supérieure/LERMA, 24 rue Lhomond, 75005 Paris, France
8 Max-Planck-Institut für Radioastonomie, Auf dem Hügel 69, 53121 Bonn, Germany
9 Astron. Dept., King Abdulaziz University, PO Box 80203, Jeddah, Saudi Arabia
Received: 22 October 2012
Accepted: 21 December 2012
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.
Key words: cosmology: observations / cosmic background radiation / cosmological parameters / quasars: absorption lines / quasars: individual: PKS 1830 / 211
© ESO, 2013
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.