J. S. Alcaniz

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We have revisited the fragment-asperity interaction model recently introduced by Sotolongo-Costa and Posadas [Phy. Rev. Lett. 92, 048501 (2004)] by considering a different definition for mean values in the context of Tsallis nonextensive statistics and introducing a scale between the earthquake energy and the size of fragment epsilon proportional to r3. The(More)
The ages of two old galaxies (53W091, 53W069) at high redshifts are used to constrain the value of the cosmological constant in a flat universe (ΛCDM) and the density parameter Ω M in Friedmann-Robertson-Walker (FRW) models with no Λ-term. In the case of ΛCDM models, the quoted galaxies yield two lower limits for the vacuum energy density parameter, Ω Λ ≥(More)
Modified f (R) gravity in the Palatini approach has been presently applied to Cosmology as a realistic alternative to dark energy. In this concern, a number of authors have searched for observational constraints on several f (R) gravity functional forms using mainly data of type Ia supenovae (SNe Ia), Cosmic Microwave Background (CMB) radiation and Large(More)
(The dynamics of the extrinsic curvature) Abstract: The acceleration of the universe is described as a dynamical effect of the extrinsic curvature of space-time. By extending previous results, the extrinsic curvature is regarded as an independent spin-2 field, determined by a set of non-linear equations similar to Einstein's equations. In this framework, we(More)
Inspired by recent developments in particle physics, the so-called brane world cosmology seems to provide an alternative explanation for the present dark energy problem. In this paper, we use the estimated age of high-z objects to constrain the value of the cosmological parameters in some particular scenarios based on this large scale modification of(More)
Dark energy is the invisible fuel that seems to drive the current acceleration of the Universe. Its presence, which is inferred from an impressive convergence of high-quality observational results along with some apparently sucessful theoretical predictions, is also supported by the current estimates of the age of the Universe from dating of local and(More)
graphicxdcolumnbm document Some Observational Consequences of Brane World Cosmologies J. S. Alcaniz alcaniz@astro.washington.edu Astronomy Department, University of Washington, Seattle, Washington, 98195-1580, USA abstract The presence of dark energy in the Universe is inferred directly and indirectly from a large body of observational evidence. The(More)
a flat Friedmann-Robertson-Walker (FRW) type models driven by non-relativistic matter plus a smooth dark energy component parametrized by its equation of state px = ωρx (−1 ≤ ω < 0). The allowed intervals for ω and Ωm are heavily dependent on the value of the mean projected linear size l. For l ' 20h−1 − 30h−1 pc, we find Ωm ≤ 0.62, ω ≤ −0.2 and Ωm ≤ 0.17,(More)
  • B. Ascaso, N. Beńıtez, +19 authors A. Maŕın-Franch
  • 2016
The impending Javalambre Physics of the accelerating universe Astrophysical Survey (J-PAS) will be the first wide-field survey of & 8500 deg to reach the ‘stage IV’ category. Because of the redshift resolution afforded by 54 narrow-band filters, J-PAS is particularly suitable for cluster detection in the range z<1. The photometric redshift dispersion is(More)