Research
Cosmological models
The standard ΛCDM cosmological model is built upon dark matter and a dark energy as main, unknown constituents of the energy content of the Universe. Much of current research aims at finding their physical nature, exploring alternative models and their departures from the standard model predictions. Recent tensions in the determination of central parameters as the Hubble constant from different observations might be an insight to new physics. In addition, inflation provides a possibly unique explanation for the generation of primordial density perturbations but it is still awaiting a final proof from observations. Our work deal with several cosmologies beyond the standard model and derives their effects on large-scale structure observations.
Emilio Bellini, Chiara Moretti, Emiliano Sefusatti, Francesco Verdiani, Matteo Viel
Recent publications
Euclid Collaboration: Bose, Carrilho, Marinucci, Moretti, et al. , Euclid preparation TBD. Modelling spectroscopic clustering on mildly nonlinear scales in beyond-ΛCDM models, arXiv:2311.13529
Song, Hu, Ruan, Moretti, Monaco, An implementation of nDGP gravity in Pinocchio, arXiv:2311.10823v1
Carrilho, Moretti, Tsedrik, Probing solutions to the S8 tension with galaxy clustering, arXiv:2310.07344
Danieli, Kobayashi, Bartolo, Matarrese, Viel, Anharmonic Effects on the Squeezing of Axion Perturbations, arXiv:2309.13112
Moradinezhad Dizgah, Bellini, Keating, Probing Dark Energy and Modifications of Gravity with Ground-Based Millimeter-Wavelength Line Intensity Mapping, arXiv:2304.08471
Matos, Bellini, Calvão, Kunz,Testing gravity with gravitational wave friction and gravitational slip, arXiv:2210.12174
Galaxy clustering
The distribution of galaxies at large scales, although indirect, is one of the primary probes of matter perturbations. The analysis of its statistical properties at the largest scales allows us to place constraints on the initial conditions of the Universe and inflation as well as on its expansion history and on the models attempting to explain the mysterious accelerated expansion. We work on the theoretical modelling of summary statistics such as the galaxy power spectrum and bispectrum, on their numerical estimators in simulations and observational data-sets and their likelihood analysis .
Emilio Bellini, Pierluigi Monaco, Chiara Moretti, Kevin Pardede, Federico Rizzo, Jacopo Salvalaggio, Elena Sarpa, Emiliano Sefusatti, Francesco Verdiani, Matteo Viel
Recent publications
Salvalaggio, Castiblanco, Noreña, Sefusatti, Monaco, Bispectrum non-Gaussian Covariance in Redshift Space, arXiv:2403.08634
Pezzotta, Moretti, Zennaro, Moradinezhad, Crocce, Sefusatti, Ferrero, Pardede, Eggemeier et al., Euclid preparation. TBD. Galaxy power spectrum modelling in real space, arXiv:2312.00679
Song, Hu, Ruan, Moretti, Monaco, An implementation of nDGP gravity in Pinocchio, arXiv:2311.10823v1
Gambardella, Biagetti, Moretti, Sefusatti, On the range of validity of perturbative models for galaxy clustering and its uncertainty, arXiv:2311.04608
Carrilho, Moretti, Tsedrik, Probing solutions to the S8 tension with galaxy clustering, arXiv:2310.07344
Lyman-alpha forest & IGM
The Lyman-𝛼 forest is the main manifestation of the high redshift intergalactic cosmic-web. It is visible in the spectra of quasars (QSOs) and produced by the scattering of the background photons with the neutral hydrogen atoms along the line-of-sight. The Lyman-𝛼 forest is a unique probe of geometry and the dynamical state of the Universe, probing diffuse matter around galaxies and in the intergalactic medium (IGM) in regimes which are not covered by other observables, both in terms of redshifts and scales.
In terms of fundamental physics, it is used to constrain dark matter free-streaming and warm dark matter models (sterile neutrinos, gravitinos), fuzzy dark matter, dark photon dark matter, primordial black holes, isocurvature models, interacting dark matter-dark energy scenarios, early dark energy, mass of active neutrinos.
In general, any cosmological model which has an impact on the linear matter power spectrum at small 0.1-100 Mpc scales and z=2-6 can be constrained by the forest.
Matteo Viel
21 cm intensity mapping
Doing hydrogen intensity mapping (HI IM) means mapping the neutral hydrogen --an optimal tracer of matter structures in the Universe-- through its characteristic spectral line of wavelength 21 cm without resolving the single emitting sources (the galaxies) but instead integrating all incoming radiation at that wavelength. HI IM probes large sky areas (the technique allows fast scanning) yet preserves the spectral information of the 21cm line, i.e. exquisite redshift information. These tomographic volumes of the Universe represent a cosmology-rich probe; indeed, many instruments worldwide are deploying it (e.g., CHIME, MeerKAT) or planning to do so (e.g. Bingo, Tianlai, Fast, HIRAX and eventually the SKAO).
Emilio Bellini, Isabella Carucci, Matteo Viel
