Zobrazeno 1 - 10
of 152
pro vyhledávání: '"Leandros Perivolaropoulos"'
Publikováno v:
Universe, Vol 10, Iss 4, p 184 (2024)
The standard cosmological model, known as ΛCDM, has been remarkably successful in providing a coherent and predictive framework for understanding the Universe’s evolution, its large-scale structure, and cosmic microwave background (CMB) radiation
Externí odkaz:
https://doaj.org/article/f086fd279b5f406c82ab1f425c7d1227
Publikováno v:
Universe, Vol 9, Iss 7, p 317 (2023)
We investigate the evolution of gravitational waves through discontinuous evolution (transition) of the Hubble expansion rate H(z) at a sudden cosmological singularity, which may be due to a transition of the value of the gravitational constant. We f
Externí odkaz:
https://doaj.org/article/976a77efd557411f902682a05b64d28b
Publikováno v:
Universe, Vol 8, Iss 10, p 502 (2022)
We reanalyze in a simple and comprehensive manner the recently released SH0ES data for the determination of H0. We focus on testing the homogeneity of the Cepheid+SnIa sample and the robustness of the results in the presence of new degrees of freedom
Externí odkaz:
https://doaj.org/article/cf2ecfdcd62246cd8711c180e520f56d
Autor:
Leandros Perivolaropoulos
Publikováno v:
Universe, Vol 8, Iss 5, p 263 (2022)
It has recently been suggested that a gravitational transition of the effective Newton’s constant Geff by about 10%, 50–150 Myrs ago could lead to the resolution of both the Hubble crisis and the growth tension of the standard ΛCDM model. Hints
Externí odkaz:
https://doaj.org/article/c666a9ba226a426db4084ac7ed5751ac
Publikováno v:
Universe, Vol 7, Iss 10, p 366 (2021)
We use an up-to-date compilation of Tully–Fisher data to search for transitions in the evolution of the Tully–Fisher relation. Using an up-to-date data compilation, we find hints at ≈3σ level for a transition at critical distances Dc≃9 Mpc a
Externí odkaz:
https://doaj.org/article/cf57150ac4824a258c45ba2322a38b74
Publikováno v:
Universe, Vol 7, Iss 8, p 300 (2021)
We present a detailed and pedagogical analysis of recent cosmological data, including CMB, BAO, SnIa and the recent local measurement of H0. We thus obtain constraints on the parameters of these standard dark energy parameterizations, including ΛCDM
Externí odkaz:
https://doaj.org/article/a79edddf33e54d55a02bb119379fb1f9
Autor:
Leandros Perivolaropoulos
Publikováno v:
Galaxies, Vol 2, Iss 1, Pp 22-61 (2014)
A wide range of large scale observations hint towards possible modifications on the standard cosmological model which is based on a homogeneous and isotropic universe with a small cosmological constant and matter. These observations, also known as
Externí odkaz:
https://doaj.org/article/aa5d56afbcfe46798765c4b320201a24
We have analysed the Pantheon+ sample using a new likelihood model that replaces the single SnIa absolute magnitude parameter $M$ used in the standard likelihood model of Brout et. al. with two absolute magnitude parameters $M_$ and a transition dist
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::8c148249d7ce7216cdcee560a764604b
Publikováno v:
Monthly Notices of the Royal Astronomical Society. 504:3956-3962
Many late time approaches for the solution of the Hubble tension use late time smooth deformations of the Hubble expansion rate $H(z)$ of the Planck18/$\Lambda$CDM best fit to match the locally measured value of $H_0$ while effectively keeping the co
We generalize the symmetron screening mechanism by allowing for an explicit symmetry breaking of the symmetron $\phi^4$ potential. A coupling to matter of the form $A(\phi)=1+\frac{\phi^2}{M^2}$ leads to an explicitly broken symmetry with effective p
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::409dfef78d783be3bfd4423b1be1f8b6
http://arxiv.org/abs/2203.10374
http://arxiv.org/abs/2203.10374