Prépublication
· 2026 arXiv
EN
The CMB constrains the gravitational constant $G$ at recombination to a few percent of its laboratory value, but the effect of $G$ on recombination itself is usually absorbed into a global fit rather than made explicit. We return to the semi-analytic descripti...
Brahim Lamine, Sébastien Beauchamp et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Line intensity mapping (LIM) provides a unique window into the high-redshift universe, but the separation of signals from overlapping emission lines and bright continuum foregrounds remains a central analysis challenge. At millimeter wavelengths in particular,...
Carlos E. Sierra, Kirit S. Karkare
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
In Inflation without an Inflaton (IWI), a de Sitter (dS) background drives inflation, and the graviton bilinear generates scalar perturbations at second order, with no inflaton or additional fundamental scalar field. We investigate how this scenario can accoun...
Raul Jimenez, Daniele Bertacca et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
We investigate the global dynamics and cosmological viability of non-singular solutions in an anisotropic Bianchi type I universe featuring an interacting vacuum energy component $V$ and a perfect fluid $ρ$, extending previous work based on a Robertson-Walker...
Marco Bruni, Rodrigo Maier et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
It is conventionally believed that the Stochastic Gravitational-Wave Background (SGWB) from inflation provides information about the earliest universe. However, in this Letter, we present a different picture. Our analysis starts from the observation that the i...
Hongguang Zhang, Zhengyang Qiu et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Forthcoming cosmic microwave background (CMB) experiments are targeting ambitious science goals, including the exploration of the particle content of the Universe across cosmic times and the search for the faint signal from primordial gravitational waves. To p...
Camille Demay, Magdy Morshed et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Galaxy-to-galaxy stochasticity may be less important for reionization, IGM heating, and the 21-cm signal than commonly assumed. We find that most of its apparent impact arises because introducing or removing scatter changes the mean emissivity of the galaxy po...
Shihai Zhu, Yuxiang Qin
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
The cosmic reheating is an important epoch in the very early Universe, and has significant impacts on the primordial black hole (PBH) abundance and the scalar-induced gravitational wave (SIGW) spectrum. The relevant energy scale and the constituents of cosmic...
Qi-Lin Yang, Shi-Jie Wang et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Ongoing stage IV galaxy surveys such as DESI or Euclid offer an unprecedented amount of information to study the large-scale structure of the Universe by mapping tens of millions of galaxies. Within the context of cosmic voids, already released and future cata...
Óscar Monllor-Berbegal, Susana Planelles et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
The LiteBIRD satellite mission aims to measure the tensor-to-scalar ratio $r$ with unprecedented sensitivity through observations of the cosmic microwave background (CMB) $B$-mode polarisation. Robust constraints on $r$ require accurate likelihood modelling ac...
G. Galloni, P. Campeti et al.
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Ground-based cosmic microwave background (CMB) experiments filter their time-ordered data to remove $1/f$ noise and ground pickup, which removes or mixes the large angular scales where primordial $B$ modes peak. A common remedy is a pseudo-$C_\ell$ estimator w...
Giacomo Galloni
#astro-ph.CO
Prépublication
· 2026 arXiv
EN
Contemporary large-scale structure analyses center around the galaxy power spectrum, modeled with one-loop perturbation theory. This description naturally breaks down at large wavenumbers, prohibiting the extraction of cosmological information from small-scale...
Oliver H. E. Philcox
#astro-ph.CO