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Centro de Astrofísica da Universidade do Porto

Structure Formation with Scalar Fields

P. T. P. Viana, A. Liddle

We discuss structure formation models where a presently evolving scalar field behaves dynamically either as a decaying cosmological constant or as dust. We find that the first case provides a successful alternative to classical cosmological constant models, keeping all the characteristics that have made these some of the most able models in reproducing the available observational data, and with the added possibility of a different recent background evolution for the Universe. We allow the presence of spatial perturbations in the scalar field, and study their effect on the growth of adiabatic energy density perturbations in a cold dark matter component. We consider two alternatives for the scalar field potential: an exponential and that associated with a pseudo-Nambu Goldstone boson.

Astrophysics and Space Science
Volume 261, Page 291
January 1999

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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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