Tootfinder

Probing the H0 Tension with Holographic Dark Energy in Unimodular Gravity: Insights from DESI DR2
Francisco Plaza, Gabriel Le\'on, Lucila Kraiselburd
https://arxiv.org/abs/2508.21175

Probing the H0 Tension with Holographic Dark Energy in Unimodular Gravity: Insights from DESI DR2
Motivated by the recent baryon acoustic oscillation measurements of DESI DR2 collaboration, this works presents an extended analysis of a cosmological model based on holographic dark energy within the framework of Unimodular Gravity. We probe the model with an extensive set of observations: cosmic chronometers, Pantheon Plus$+$SH0ES Type Ia supernovae, DESI DR2 BAO distances, quasar X-ray/UV fluxes (two independent calibrations), and Planck 2018 CMB data. The results are analyzed to assess the …

Deflection of light and time delay in hyperbolic Einstein-Straus--de Sitter solution
Mourad Guenouche
https://arxiv.org/abs/2507.11792 https://

Deflection of light and time delay in hyperbolic Einstein-Straus--de Sitter solution
We analyze strong gravitational lensing by a spherically symmetric mass distribution within the Einstein-Straus-de Sitter framework in a spatially open Universe with negative curvature ($k = -1$). Applying the theory to the lensed quasar SDSS J1004+4112, we identify a critical threshold for the current scale factor $a_0$ of approximately $2.6 \times 10^{27}$ m, below which the effects of negative spatial curvature on lensing observables become significant, corresponding to a current curvature d…

First constraints on the local ionization topology in front of two quasars at z ~ 7.5
Timo Kist, Joseph F. Hennawi, Frederick B. Davies, Eduardo Ba\~nados, Sarah E. I. Bosman, Zheng Cai, Anna-Christina Eilers, Xiaohui Fan, Zolt\'an Haiman, Hyunsung D. Jun, Yichen Liu, Jinyi Yang, Feige Wang
https://arxiv.org/abs/2508.21818

First constraints on the local ionization topology in front of two quasars at z ~ 7.5
Thus far, Lyman-$α$ damping wings towards quasars have been used to probe the \textit{global} ionization state of the foreground intergalactic medium (IGM). A new parameterization has demonstrated that the damping wing signature also carries \textit{local} information about the distribution of neutral hydrogen (HI) in front of the quasar before it started shining. Leveraging a recently introduced Bayesian \texttt{JAX}-based Hamiltonian Monte Carlo (HMC) inference framework, we derive constrain…