Résultats pour « astro-ph.CO »

Prépublication · 2026 arXiv EN

Mean-Field Backreaction in Single-Field Inflation

The validity of linear perturbation theory and the role of backreaction in single-field inflationary models that enhance power at small scales have recently been under debate. We investigate scalar backreaction semi-analytically in a mean-field approach within...

Matteo Braglia, Gabriele Franciolini et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Neutrino self-interactions in light of DESI and CMB-SPA

We present an updated analysis of non-standard neutrino self-interactions, where the interaction is effectively mediated by a heavy particle, using the latest available data from DESI and the CMB. The considered data include combinations of DESI DR1 full-shape...

Hernán E. Noriega, Josue De-Santiago et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Evolving only the observed spacetime region: perfectly parallel lightcone simulations with sCOLA

Cosmological analyses of Stage-IV galaxy surveys require large ensembles of lightcone mock catalogues, but a full survey-scale $N$-body run costs of order $10^7$ CPU hours, putting such ensembles out of reach. We present a framework that produces survey-scale...

Mayeul Aubin, Florent Leclercq et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

ERGO-ML and how to directly infer the multi-temperature nature of intra-cluster gas: simulation-based inference with TNG-Cluster

Though galaxy clusters are virialized and mostly in thermodynamic equilibrium, their internal gas thermodynamics are complex. The hot gas is multiphase and spatially inhomogeneous. The exact state of the gas contains important information about the internal ph...

Joey Braspenning, Annalisa Pillepich et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Exploring the Evidence for Evolving Dark Energy with the Jeffreys prior

We investigate the impact of applying the uninformative Jeffreys prior in a re-analysis of DESI DR2 BAO, Planck 2018 CMB, and Type Ia Supernovae (DES-SN5YR, DES-Dovekie, Pantheon+, Union3). We incorporate this prior into new posterior inference and evidence ca...

Joshua Layton, Alex Hall et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Joint Fit of Galaxy Cluster Scaling Relations from Individual Weak Lensing Data: Comparison with Stacked Analysis and a Real Data Test

Stacking is the standard route to signal-to-noise in cluster weak lensing, but it destroys the cluster-by-cluster information that scaling-relation studies need. We instead fit every cluster's individual $ΔΣ$ profile simultaneously, tying its mass and concentr...

André Z. Vitorelli, Eduardo S. Cypriano #astro-ph.CO

Prépublication · 2026 arXiv EN

Revisiting the Mass and Scale Dependence of the "Lensing is Low" Effect with DECADE

Galaxy-galaxy lensing (GGL) is a critical probe of cosmology and galaxy formation. However, predicted GGL amplitudes tend to be $\sim 20-40\%$ higher than observations, primarily on small scales, a tension called the lensing-is-low problem. If not resolved thr...

Kimiko Queen, Abigail V. Fisher et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Gravitational Waves as a Probe of Multi-Fluid Cosmologies: General Formalism and the Case of Cosmological Stasis

Scalar-induced gravitational waves (SIGWs) provide a powerful probe of the expansion history of the universe prior to the Big Bang. Indeed, the production of such gravity waves depends on the evolution of first-order scalar perturbations within the early unive...

Keith R. Dienes, Fazlollah Hajkarim et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Clustering of JWST LRDs. Implications for PBHs and other early-forming seeds

We use the observed abundance and spatial clustering of JWST little red dots (LRDs) over z = 4--8 to confront two formation scenarios: the standard picture in which LRDs form in virialized dark-matter halos, and one in which they are seeded by a dynamically su...

Gert Hütsi #astro-ph.CO

Prépublication · 2026 arXiv EN

Does the inverse distance ladder rule out late-time solutions to the Hubble tension? A model-independent test using DES-Dovekie supernovae and DESI DR2 BAO

It has been argued that the inverse distance ladder disfavours late-time solutions to the Hubble tension. We test this with a cosmographic expansion where $H$ is a fourth-order polynomial in $1 - a$. We combine the uncalibrated DES-Dovekie SNIa with DESI~DR2 B...

José Antonio Nájera, Indranil Banik et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Galaxy bias of radio AGN and star-forming galaxies from MIGHTEE and CMB lensing

Radio galaxies play a significant role in galaxy evolution through feedback mechanisms, making it important to characterize the environments in which they reside. We measure the cross-correlation between the positions of radio sources in the MIGHTEE survey and...

Joel Hamlett, Catherine L. Hale et al. #astro-ph.CO

Prépublication · 2026 arXiv EN

Possible detection of Baryon Acoustic Oscillations imprinted in the HI sources from the FASHI catalog

Motivated by curiosity as to whether the observed Universe at low redshifts is well described by the concordance cosmological model, we investigate the large scale angular clustering of extragalactic neutral hydrogen HI sources in the local Universe. Using the...

Felipe Avila, Camila Franco et al. #astro-ph.CO