activity
20242026
collaborators

11 papers

gr-qc2026

Supermassive black hole seeds from direct collapse of CDM-curvature peaks

Marco Galoppo, Marco Bruni, Tomohiro Harada

We study black hole (BH) formation from the nonlinear growth and collapse of primordial perturbations during the matter-dominated era. Modelling cold dark matter (CDM) as pressurel…

gr-qc2026

When Weak Fields Arent Weak: Post-Newtonian effective theory and the Dark Matter Puzzle

Marco Galoppo, Giorgio Torrieri

Post-Newtonian theory is considered a reliable effective expansion of General Relativity in the weak-field and slow-motion limit. We argue that such a belief is misplaced. In gener…

astro-ph.CO2026

Backreaction and the Role of Spatial Curvature in the Cosmic Neighborhood

Marco Galoppo, Thomas Buchert, Pierre Mourier

We present the first direct computation of spatially averaged dynamical quantities in the local Universe, employing the Cosmicflows-4++ reconstruction and a covariant scalar averag…

astro-ph.CO2026

An effective -Szekeres modelling of the local Universe with Cosmicflows-4

Marco Galoppo, Leonardo Giani, Morag Hills +1

We develop an effective description of the local cosmic environment, namely, for redshift , to quantify the bias induced by local structure on cosmological observab…

astro-ph.HE2026

SN 2019vxm: A Shocking Coincidence between Fermi and TESS

Zachary G. Lane, Ryan Ridden-Harper, Sofia Rest +37

Shock breakout and, in some cases, jet-driven high-energy emission are increasingly recognized as key signatures of the earliest phases of core-collapse supernovae, especially in T…

gr-qc2025

Cosmological perturbations on an averaged background

Marco Galoppo, Pierre Mourier

In relativistic cosmology, the formation of nonlinear inhomogeneities can induce non-negligible backreaction on late-time expansion. Among the important consequences for precision…