activity
20092026
most citedDoes the growth of structure affect our dynamical models of the universe? The averaging, backreaction and fitting problems in cosmology

220 citations · 1.2k across the 39 of their papers we have counts for

collaborators

39 papers

gr-qc2026

Gravitational edge mode powers galaxy flat rotation curves

Obinna Umeh

The point-particle approximation is foundational to modelling clustering of matter in the universe, but is fundamentally inconsistent within General Relativity due to associated sp…

astro-ph.CO2026

Cosmological zoom-in perturbation theory as a consistent beyond point-particle approximation framework

Obinna Umeh

Modelling structure formation across the full dynamical range of the Universe remains a major challenge in cosmology. This difficulty originates from a fundamental limitation of ge…

astro-ph.CO2026

An essential building block for cosmological zoom-in perturbation theory

Obinna Umeh

The evolution of large-scale structure within the standard model of cosmology is well posed only up to the onset of shell crossing, where particle trajectories appear to intersect.…

astro-ph.CO2023★ 4 cited

The HI intensity mapping power spectrum: insights from recent measurements

Hamsa Padmanabhan, Roy Maartens, Obinna Umeh +1

The first direct measurements of the HI intensity mapping power spectrum were recently made using the MeerKAT telescope. These measurements are on nonlinear scales, at redshifts 0.…

astro-ph.CO2023

Vorticity generation in cosmology and the role of shell crossing

Obinna Umeh

There is no source for cosmic vorticity within the cold dark matter cosmology. However, vorticity has been observed in the universe, especially on the scales of clusters, filaments…

astro-ph.CO2022★ 3 cited

Emergence of smooth distance and apparent magnitude in a lumpy Universe

Obinna Umeh

The standard interpretation of observations such as the peak apparent magnitude of Type Ia supernova made from one location in a lumpy Universe is based on the idealised Friedmann-…