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Centro de Astrofísica da Universidade do Porto

Looking for a varying α in the cosmic microwave background

P. P. Avelino, C. J. A. P. Martins, G. Rocha, P. T. P. Viana

Abstract
We perform a likelihood analysis of the recently released BOOMERanG and MAXIMA data, allowing for the possibility of a time-varying fine-structure constant. We find that in general these data prefer a value of α that was smaller in the past (which is in agreement with measurements of α from quasar observations). However, there are some interesting degeneracies in the problem which imply that strong statements about α cannot be made using this method until independent accurate determinations of Ωbh2 and H0 are available. We also show that a preferred lower value of α comes mainly from the data points around the first Doppler peak, whereas the main effect of the high-l data points is to increase the preferred value for Ωbh2 (while also tightening the constraints on Ω0 and H0). We comment on some implications of our results.

Physical Review D
Volume D62, Page 123508
December 2000

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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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