Browsing by Author "Verdugo, Tomas"

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    Barrow Entropy Cosmology: an observational approach with a hint of stability analysis
    (2021) Leon, Genly; Magana, Juan; Hernandez-Almada, A.; Garcia-Aspeitia, Miguel A.; Verdugo, Tomas; Motta, V
    In this work, we use an observational approach and dynamical system analysis to study the cosmological model recently proposed by Saridakis (2020), which is based on the modification of the entropy-area black hole relation proposed by Barrow (2020). The Friedmann equations governing the dynamics of the Universe under this entropy modifica-tion can be calculated through the gravity-thermo dynamics conjecture. We investigate two models, one considering only a matter component and the other including matter and ra-diation, which have new terms compared to the standard model sourcing the late cosmic acceleration. A Bayesian analysis is performed in which using five cosmological observations (observational Hubble data, type Ia supernovae, HII galaxies, strong lensing systems, and baryon acoustic oscillations) to constrain the free parameters of both models. From a joint analysis, we obtain constraints that are consistent with the standard cosmological paradigm within 2a-confidence level. In addition, a complementary dynamical system analysis using local and global variables is developed which allows obtaining a qualitative description of the cosmology. As expected, we found that the dynamical equations have a de Sitter solution at late times.
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    Dissecting the Strong-lensing Galaxy Cluster MS 0440.5+0204. I. The Mass Density Profile
    (2020) Verdugo, Tomas; Carrasco, Eleazar R.; Foex, Gael; Motta, Veronica; Gomez, Percy L.; Limousin, Marceau; Magana, Juan; de Diego, Jose A.
    We present a parametric strong-lensing modeling of the galaxy cluster MS 0440.5+0204 (located at z = 0.19). We have performed a strong-lensing mass reconstruction of the cluster using three different models. The first model uses the image positions of four multiply imaged systems (providing 26 constraints). The second one combines strong-lensing constraints with dynamical information (velocity dispersion) of the cluster. The third one uses the mass calculated from weak lensing as an additional constraint. Our three models reproduce equally well the image positions of the arcs, with an rms image equal to approximate to 0.'' 5 However, in the third model, the inclusion of the velocity dispersion and the weak-lensing mass allows us to obtain better constraints in the scale radius and the line-of-sight velocity dispersion of the mass profile. For this model, we obtain r(s), = 132(-32)(+30) kpc, sigma(s) = 1203(-47)(+46) km s(-1), M-200 = 3.1(-0.6)(+0.6) x10(14) M-circle dot, and a high concentration c(200) = 9.9(-1.4)(+2.2). Finally, we used our derived mass profile to calculate the mass up to 1.5 Mpc. We compare it with X-ray estimates previously reported, finding a good agreement.