Trieste (Italy)

Matteo Viel

Welcome to my homepage. I am Full Professor in the Astroparticle Physics Group at SISSA . Before that I was staff researcher at INAF-OATS. Before that I was a PPARC Fellow at the Institute of Astronomy of the University of Cambridge and a Research Fellow at Clare Hall College.

Research Areas     Contact and Personal Information
Intergalactic Medium: the Lyman-alpha forest -- is the absorption produced by neutral hydrogen seen in the spectra of background quasars. I am interested in using the Lyman-alpha forest to recover the linear dark matter power spectrum at scales of 1-40 comoving Mpc which are not probed by other observables. I am interested in using the intergalactic medium to constrain standard and non-standard cosmological scenarios (e.g. interactions between dark energy and dark matter, properties of dark matter) and the masses of cosmological neutrinos.

Intensity Mapping @ 21cm: -- is the electromagnetic radiation spectral line that is created by a change in the energy state of neutral hydrogen atoms, it is an emission process and can probe the large scale structure in a way complementary to the IGM absorption. The signal is modelled both analytically or with hydro simulations.

The nature of dark matter -- I am using hydro-dynamical simulations and high resolution data to constraints the properties of dark matter at the small scales (cold/warm dark matter and sterile neutrinos), in particular non cold dark matter models like: thermal WDM, fuzzy DM, mixed models, sterile neutrinos.

Structure formation from large to small scales -- I am broadly interested in structure formation using state-of-the-art data sets like BAO, galaxy redshift surveys, weak lensing, IGM data and I try hard to disentangle between astrophysical processes and fundamental physical processes by exploiting different redshifts and scales.

Cosmological parameters estimation -- When the dark matter power spectrum inferred from Lyman-alpha quasar spectra is combined with the Cosmic Microwave Background data we can get tight constraints on cosmological parameters (sigma_8, spectral index), on inflationary models, on the mass of warm dark matter particles such as light gravitinos or sterile neutrinos.

Warm Hot Intergalactic Medium -- I am using hydro-dynamical simulations I am also addressing the impact of several different feedback mechanisms on the low redshift IGM. In general the low-z IGM is a feedback thermometer and potentially a probe of new physics via dark photon heating of the cosmic web (Bolton+22 -- see below).

Feedabck, the UV background and metal enrichment processes -- I am using hydro-dynamical simulations to give constraints on the amplitude and shape of the UV background and on the metal enrichment at z=3. I rely on a modified version of the hydrodynamic code (G-II) that incorporates a chemodynamical model with feedback recipes.

via Bonomea, 265
I-34136 Trieste
Tel: +39 040 3787517
email: viel(at)

full CV: [pdf-file]

Publications at ADS  Publications at arXiv  Publications at INSPIRE-HEP  

cosmoIGM: ERC: cosmoIGM publications (draft version)

cosmoIGM: ERC: cosmoIGM final activity report (draft version)

Google Scholar link

NEWS: National Center of Super Computing - Official start of Astrophysics and Cosmos Observations activities

NEWS: Physics Magazine: heating up dark matter with the IGM

Teaching @ PhD Winter School 2022 - Tenerife (November 2022):
Lecture 1 Intensity Mapping
Lecture 2 IGM
Lecture 3 Galaxy Clustering
Lecture 4 Weak lensing and GCs

teaching: Structure formation lectures at SISSA (since 2011)

teaching: Lecture on neutrinos and large scale structure

outreach: Trieste next event - La scienza del futuro
outreach: local press article
outreach: Youtube interview in Italian outreach: DM LECTURE ON YOUTUBE - SISSA FREE Cosmology online course edited by P. Salucci outreach: Public conference (youtube link)

seminar: Seminar at Simons CCA - New York Feb. 2020 - youtube link

seminar: talk @ Fundamental Cosmology Meeting - Granada - Nov 22

Recent Publications     Full List of publications     Links
JWST high-z galaxies constraints on warm and cold dark matter models
Maio, Umberto; Viel, Matteo
PREPRINT eprint arXiv:2211.03620 arXiv:2211.03620

Testing gravity with gravitational waves X electromagnetic probes cross-correlations
Scelfo, Giulio; Berti, Maria; Silvestri, Alessandra; Viel, Matteo
PREPRINT eprint arXiv:2210.02460 arXiv:2210.02460

Multipole expansion for 21cm Intensity Mapping power spectrum: forecasted cosmological parameters estimation for the SKA Observatory
Berti, Maria; Spinelli, Marta; Viel, Matteo
PREPRINT eprint arXiv:2209.07595 arXiv:2209.07595

Studying the Warm Hot Intergalactic Medium in emission: a reprise
Parimbelli, G. ; Branchini, E. ; Viel, M. ; Villaescusa-Navarro, F. ; ZuHone, J.
PREPRINT eprint arxXiv:2209.00657

Hints of dark photon dark matter from observations and hydrodynamical simulations of the low-redshift Lyman-alpha forest
Bolton, James S.; Caputo, Andrea ; Liu, Hongwan ; Viel, Matteo
PREPRINT eprint arXiv:2206.13520 - Phys. Rev. Lett. 129, 211102 (2022)

The Sherwood-Relics simulations: overview and impact of patchy reionization and pressure smoothing on the intergalactic medium
Puchwein, Ewald ; Bolton, James S. ; Keating, Laura C. ; Molaro, Margherita ; Gaikwad, Prakash ; Kulkarni, Girish ; Haehnelt, Martin G. ; Irsic, Vid ; Soltinsky, Tomas ; Viel, Matteo ; Aubert, Dominique ; Becker, George D. ; Meiksin, Avery
PREPRINT eprint arXiv:2207.13098

Weighing cosmic structures with clusters of galaxies and the intergalactic medium
Esposito, Matteo; Irsic, Vid ; Costanzi, Matteo ; Borgani, Stefano ; Saro, Alexandro ; Viel, Matteo
Monthly Notices of the Royal Astronomical Society, Volume 515, Issue 1, pp.857-870 arXiv:2202.00974

Science (archives, institutes & computing centers):

RTN network "The Physics of the IGM"
INAF Istituto Nazionale di Astrofisica
INFN Istituto Nazionale di Fisica Nucleare
Physics Department Trieste University
Dipartimento di Fisica e Astronomia Padova
MPA Garching - Germany
Institute of Astronomy Cambrige - UK
COSMOS supercomputer DAMTP, Cambridge - UK
Darwin Cluster High Performance Computer Service (HPCS) Cambridge - UK
PACO VILLAESCUSA's public software