Search Publications
Negative cosmological constant in the dark energy sector: tests from JWST photometric and spectroscopic observations of high-redshift galaxies
Menci, Nicola; Sen, Anjan A.; Vagnozzi, Sunny +2 more
Early observations with the James Webb Space Telescope (JWST) have revealed the existence of an unexpectedly large abundance of extremely massive galaxies at redshifts z ≳ 5: these are in tension with the predictions not only of the standard ΛCDM cosmology, but also with those of a wide class of dynamical dark energy (DE) models, and are generally…
A double take on early and interacting dark energy from JWST
Melchiorri, Alessandro; Mena, Olga; Nunes, Rafael C. +4 more
The very first light captured by the James Webb Space Telescope (JWST) revealed a population of galaxies at very high redshifts more massive than expected in the canonical ΛCDM model of structure formation. Barring, among others, a systematic origin of the issue, in this paper, we test alternative cosmological perturbation histories. We argue that…
A hidden population of active galactic nuclei can explain the overabundance of luminous z > 10 objects observed by JWST
Furlanetto, Steven R.; Hegde, Sahil; Wyatt, Michael M.
The first wave of observations with JWST has revealed a striking overabundance of luminous galaxies at early times (z > 10) compared to models of galaxies calibrated to pre-JWST data. Early observations have also uncovered a large population of supermassive black holes (SMBHs) at z > 6. Because many of the high-z objects appear extended, the…
Model-independent reconstruction of UV luminosity function and reionization epoch
Hazra, Dhiraj Kumar; Adak, Debabrata; Mitra, Sourav +1 more
We conduct a first comprehensive study of the Luminosity Function (LF) using a non-parametric approach. We use Gaussian Process to fit available luminosity data between redshifts z ∼ 2-8. Our free-form LF in the non-parametric approach rules out the conventional Schechter function model to describe the abundance-magnitude relation at redshifts z=3…