Abstract The very first light captured by the James Webb Space Telescope (JWST) revealed a population of galaxies at high redshifts more massive than expected in canonical ΛCDM model structure formation. Barring, among others, systematic origin issue, this paper, we test alternative cosmological perturbation histories. We argue that models with larger matter component Ω m and/or scalar spectral index n s can substantially improve fit to JWST measurements. In regard, phenomenological...

ABSTRACT Inflationary gravitational waves, behaving as additional radiation in the Early Universe, can increase effective number of relativistic species (Neff) by a further correction that depends on integrated energy-density waves over all scales. This effect is typically used to constrain (blue-tilted) models inflation light bounds resulting from big bang nucleosynthesis. In this paper, we recompute contribution, discussing some caveats state-of-the-art analyses. Through parametric...

In light of the most recent cosmological observations, we provide new updated constraints on slow roll inflation in different extended scenarios beyond $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model. Along with usual six parameters, simultaneously vary combinations additional including running scalar spectral index ${\ensuremath{\alpha}}_{s}$, its ${\ensuremath{\beta}}_{s}$, tensor amplitude $r$ and spatial curvature ${\mathrm{\ensuremath{\Omega}}}_{k}$. From Planck 2018 data, find no...

Abstract The recent observations from the James Webb Space Telescope have led to a surprising discovery of significant density massive galaxies with masses M ≥ 10 10.5 ⊙ at redshifts approximately z ∼ 10. This corresponds stellar mass roughly ρ * 6 Mpc -3 . Despite making conservative assumptions regarding galaxy formation, this finding may not be compatible standard ΛCDM cosmology that is favored by CMB Anisotropies Planck satellite. In paper, we confirm substantial discrepancy Planck's...

The search for non-Gaussian signatures in the cosmic microwave background (CMB) is crucial understanding physics of early Universe. Given possibility fluctuations CMB, a recent revision to standard $\mathrm{\ensuremath{\Lambda}}$-cold dark matter ($\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$) model has been proposed, dubbed ``super-$\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$.'' This introduces additional free parameters account potential effects trispectrum primordial fluctuations. In this...

The parameter $\sigma_8$ represents the root-mean-square (rms) mass fluctuations on a scale of $R_8=8h^{-1}$ Mpc and is commonly used to quantify amplitude matter at linear cosmological scales. However, dependence $R_8$ $h$ complicates direct comparisons values obtained under different assumptions about $H_0$, since in such cases characterizes amount structure physical This issue arises both when comparing from fitting analyses models with differing $H_0$ posteriors, contrasting constraints...

The recent observations from the James Webb Space Telescope have led to a surprising discovery of significant density massive galaxies with masses $M \ge 10^{10.5} M_{\odot}$ at redshifts approximately $z\sim 10$. This corresponds stellar mass roughly $\rho_*\sim 10^6 M_{\odot} Mpc^{-3}$. Despite making conservative assumptions regarding galaxy formation, this finding may not be compatible standard $\Lambda$CDM cosmology that is favored by CMB Anisotropies Planck satellite. In paper, we...

The search for non-Gaussian signatures in the Cosmic Microwave Background (CMB) is crucial understanding physics of early Universe. Given possibility fluctuations CMB, a recent revision to standard $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model has been proposed, dubbed "Super-$\Lambda$CDM". This introduces additional free parameters account potential effects trispectrum primordial fluctuations. In this study, we explore impact Super-$\Lambda$CDM on current constraints neutrino physics....

Over the past decades, advancements in observational cosmology have introduced us an era of precision cosmology, dramatically enhancing our understanding Universe's history as well bringing new tensions to light. Observations Cosmic Microwave Background, large-scale structure, and distant galaxies provided unprecedented insights into processes that shaped Universe. This PhD thesis contributes this research by exploring how these cosmic observables can be leveraged constrain physics beyond...

Inflationary gravitational waves, behaving as additional radiation in the Early Universe, can increase effective number of relativistic species ($N_{\rm eff}$) by a further correction that depends on integrated energy-density waves over all scales. This effect is typically used to constrain (blue-tilted) models inflation light bounds resulting from Big Bang Nucleosynthesis. In this paper, we recompute contribution, discussing some caveats state-of-the-art analyses. Through parametric...

The very first light captured by the James Webb Space Telescope (JWST) revealed a population of galaxies at high redshifts more massive than expected in canonical $\Lambda$CDM model structure formation. Barring, among others, systematic origin issue, this paper, we test alternative cosmological perturbation histories. We argue that models with larger matter component $\Omega_m$ and/or scalar spectral index $n_s$ can substantially improve fit to JWST measurements. In regard, phenomenological...