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

Tsedrik, Carrilho, Moretti, The simple way to measure evolving dark energy without prior-volume effects, arXiv:2509.09562
Verdiani, Castorina, Salvioni, Sefusatti, The Effective Field Theory of Large Scale Structure for Mixed Dark Matter Scenarios, arXiv:2507.08792
Berti, Bellini, Bonvin, Kunz, Viel, Zumalacarregui, Reconstructing the dark energy density in light of DESI BAO observations, arXiv:2503.13198
Verdiani, Bellini, Moretti, Sefusatti, Carbone, Viel, Redshift-Space Distortions in Massive Neutrinos Cosmologies, arXiv:2503.06655
Cataneo, Bellini, mochi_class: Modelling Optimisation to compute Horndeski in Class, arXiv:2407.11968
Euclid Collaboration: Bose, Carrilho, Marinucci, Moretti, et al. , Euclid preparation. XLIV. 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, Benjamin Camacho, Pierluigi Monaco, Chiara Moretti, Cecilia Oliveri, Federico Rizzo, Jacopo Salvalaggio, Elena Sarpa, Emiliano Sefusatti, Francesco Verdiani, Matteo Viel

Recent publications

Degni, Sarpa, Aubert, Branchini, Pisani, Courtois, On the extraction of Alcock-Paczynski signal from voids: a novel approach via reconstruction, arXiv.:2509.08884
Pezzotta, Eggemeier, Gambardella, Finkbeiner, Sánchez, Camacho Quevedo, Crocce, Lee, Parimbelli, Scoccimarro, Extending evolution mapping to massive neutrinos with COMET, arXiv:2503.16160
Verdiani, Bellini, Moretti, Sefusatti, Carbone, Viel, Redshift-Space Distortions in Massive Neutrinos Cosmologies, arXiv:2503.06655
Tsedrik, Lee, Markovic, Carrilho, Pourtsidou, Moretti, Bose, Huff, Robertson, Taylor, Zuntz, Interacting dark energy constraints from the full-shape analyses of BOSS DR12 and DES Year 3 measurements, arXiv:2502.03390
Elkhashab, Porciani, Bertacca, Measuring our peculiar velocity from spectroscopic redshift surveys, arXiv:2412.03953
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).

Gabriele Autieri, Emilio Bellini, Isabella Carucci, Matteo Viel

Recent publications

Bianca De Caro, Isabella Carucci, Stefano Camera, Mathieu Remazeilles, Carmelita Carbone, Needlets and foreground removal for SKAO hydrogen intensity maps, arxiv:2509.02644
Gabriele Autieri, Maria Berti, Marta Spinelli, Balakrishna Sandeep Haridasu, Matteo Viel, Weighing neutrinos with 21cm Intensity Mapping at the SKAO, arXiv:2504.18625
Isabella Carucci, José Bernal, Steven Cunnington, Mario Santos, Jingying Wang, José Fonseca, Keith Grainge, Melis Irfan, Yichao Li, Alkistis Pourtsidou, Marta Spinelli, Laura Wolz, Hydrogen intensity mapping with MeerKAT: Preserving cosmological signal by optimising contaminant separation, arXiv:2412.06750

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