Abebe, AmareCruz Dombriz, Álvaro de laDunsby, Peter K. S.2023-06-192023-06-192013-08-261550-799810.1103/PhysRevD.88.044050https://hdl.handle.net/20.500.14352/33807© 2013 American Physical Society. We would like to thank David Bacon for a comprehensive reading of the manuscript and for his useful comments. We are also indebted to Marc Manera and Ashley Ross for providing us the most updated literature about the SDSS-III project. We warmly thank as well José Beltrán for useful comments about BAO calculations. A. A. acknowledges financial support from NRF (South Africa). A. d. l. C. D. acknowledges financial support from Marie Curie–Beatriu de Pinós Contract No. BP-B00195 Generalitat de Catalunya, ACGC University of Cape Town and MINECO (Spain) Projects No. FIS2011-23000, No. FPA2011-27853-C02-01 and Consolider-Ingenio MULTIDARK Grant No. CSD2009-00064. P. K. S. D. thanks the NRF for financial support and Queen Mary, University of London for support during the final stages of this work. A. d. l. C. D. thanks the KITPC, Chinese Academy of Sciences, for its hospitality during the final stages of this work.Over the past few years much attention has been given to the study of modified gravity theories in order to find a more natural explanation for the late time acceleration of the Universe. Nevertheless, a comparison of the matter power spectrum predictions made by these theories with available data has not yet been subjected to a detailed analysis. In the context of f(R) theories of gravity we study the predicted power spectra using both a dynamical systems approach for the background and solving for the matter perturbations without using the quasistatic approximation, comparing the theoretical results with several Sloan Digital Sky Survey data. The importance of studying the first order perturbed equations by assuming the correct background evolution and the relevance of the initial conditions are also stressed. We determine the statistical significance in relation to the observational data and demonstrate their conflict with existing observations.engjournal articlehttp://dx.doi.org/10.1103/PhysRevD.88.044050http://journals.aps.org/open access53Baryon acoustic-OscillationsR-N-GravityNonlinear gravitational lagrangiansMicrowave background anisotropiesGauge-Invariant perturbationsHigh-Redshift supernovaeProbe wmap observationsHubble-Space-TelescopeDigital sky surveyCosmological perturbationsFísica (Física)22 Física