RT Journal Article T1 Cosmic vector for dark energy: Constraints from supernovae, cosmic microwave background, and baryon acoustic oscillations A1 López Maroto, Antonio A1 Beltrán Jiménez, José A1 Lazkoz, Ruth AB It has been recently shown that the presence of a vector field over cosmological scales could explain the observed accelerated expansion of the Universe without introducing either new scales or unnatural initial conditions in the early Universe, thus avoiding the coincidence problem. Here, we present a detailed analysis of the constraints imposed by supernova type Ia (SNIa), cosmic microwave background (CMB), and baryon acoustic oscillation (BAO) data on the vector dark energy model with general spatial curvature. We find that contrary to standard cosmology, CMB data exclude a flat universe for this model and, in fact, predict a closed geometry for the spatial sections. We see that CMB and SNIa Gold data are perfectly compatible at the 1-sigma level, however the SNIa Union data set exhibits a 3-sigma tension with CMB. The same level of tension is also found between SNIa and BAO measurements. PB Amer Physical Soc SN 1550-7998 YR 2009 FD 2009-07 LK https://hdl.handle.net/20.500.14352/44341 UL https://hdl.handle.net/20.500.14352/44341 LA eng NO © 2009 The American Physical Society.We would like to thank Eiichiro Komatsu for useful comments. J. B. is very grateful to the Department ofFisika Teorikoa of the EHU for their hospitality. This work has been supported by DGICYT (Spain) Project Nos. FPA 2004-02602 and FPA 2005-02327, UCMSantander PR34/07-15875, CAM/UCM 910309, and MEC grant BES-2006-12059. NO DGICYT (Spain) NO UCM-Santander NO CAM/UCM NO MEC DS Docta Complutense RD 14 jun 2025