cosmoIGM - Starting Grant

Welcome to the webpage of the cosmoIGM research project. cosmoIGM is a FP7 ERC Starting Grant that has the goal to investigate cosmology with the Intergalactic Medium.
The ERC Grant has been awarded to Matteo Viel by the European Community and will cover the period 1/12/2010 - 1/12/2015.

Research Areas     Contact and Personal Information

Summary of research proposal

The IGM as a Large-Scale Structure tracer The WMAP mission that measured the cosmic microwave background (CMB) anisotropies and the SDSS (Sloan Digital Sky Survey) that mapped the galaxy distribution out to large distances have allowed to get tight constraints on the matter distribution at large scales and to enter the era of precision cosmology. In fact, the constraints in terms of the cosmological parameters of the standard model (Cold Dark Matter, DM) have now reached an unprecedented degree of precision. However, the information on the matter distribution at small scales is completely missing and rely on few measurements of the linear dark matter power spectrum performed by Croft et al. (2002, ApJ, 581, 20); Viel, Haehnelt & Springel (2004, MNRAS, 355, 23); McDonald et al. (2005, ApJ, 635). These measurements are all based on various compilations of Lyman- quasar spectra that probe the IGM at z=2-4 and at scales between a few and one hundred Mpc. There is a tension between the cosmological parameters derived from Lyman- observations and those suggested by the large scale structure: the amplitude derived from IGM data is in fact higher at the 2 level than that measured from the CMB (Seljak et al. 2005, PhRvD, 71 3515; Viel et al. 2009, MNRAS, 393, 774). The current understanding is that the systematic uncertainties in this pristine field of research are still preventing a fully reliable measurement of the matter power spectrum at these scales and both observational and theoretical efforts are needed in order to elevate the IGM to a powerful cosmological probe.

IGM and fundamental physics The Lyman- forest is an important tool also for fundamental physics. In order to stress this point, I present here two results that IGM data provided: 1) the tightest cosmological constraints on the upper limits on the mass of neutrino masses have been obtained from Lyman- forest SDSS data (Seljak et al. 2005, PhRvD, 71, 3515) and give Sigma m_nu <0.17 eV at the 2 confidence level; 2) the tightest constraints on the coldness of cold dark matter have been obtained from a compilation of SDSS and Keck HIRES data and give m>4 keV for a thermal relic (28 keV for a sterile neutrino - Viel et al. 2008, PhRvL, 100, 041304). It is important to notice that these limits are very stringent and, if trusted, can really open up new windows on the nature of dark matter and on the constraints of neutrino masses from cosmological data also for particle physics experiments. Other IGM-related fundamental aspects are: 1) the implications that a measurement of the matter power spectrum at small scales has in terms of inflationary parameters (Seljak et al 2005, PhRvD, 71, 3515 Viel et al. 2004, MNRAS, 355, 23L); 2) impact of non-gaussian cosmological model on the flux properties (Viel et al. 09, MNRAS, 393, 774); 3) the controversial constraints in terms of variation of fine structure constant using metal line transition in high-resolution spectra (Levshakov et al. 2007 A&A, 466, 1077; Srianand et al. 2007, PhRvL, 99, 239002; Murphy et al. 2008, MNRAS, 384, 1053); 4) the most-direct measurement of the cosmic expansion that can be performed with the next generation of ultra-stable spectrograph (CODEX) on the ELT (Extremely Large Telecope, Liske et al. 2008, MNRAS, 386, 1192); 5) modifications of gravity that could alter the high-z evolution of the growth factors and the IGM properties.

The IGM/Galaxy interplay Observations of absorption features in high-z QSO absorption spectra have unveiled the widespread presence of heavy elements well outside galaxies, reaching the low density IGM. In fact, the Lyman- forest in the redshift range z = 2-3 is enriched (as traced by ions CIV, OVI, SiIV) up to 0.003 the solar value (with about 1 dex scatter) down to small column densities of neutral hydrogen, while reaching Z=0.1 solar in the local universe. Since the Lyman- forest is thought to fairly trace the low density IGM, it is also assumed as representative of the diffuse baryonic matter which traces the filamentary dark-matter structures seen in numerical simulations that extend well beyond the neighborhood of galaxies. Furthermore, it has been well known for long time that the hot plasma in galaxy clusters at low redshift is highly enriched to 0.3- 0.5 the solar value. The favorite candidates for playing a major role are the supernovae(SN)/Active Galactic Nuclei(AGN)-driven galactic outflows, perhaps coupled with some larger-scale diffusion engine. Besides enriching the IGM, galactic winds are also believed to have a crucial role in shaping the mass-metallicity relation of galaxies and influencing the IGM temperature structure. Winds driven by the ram-pressure exerted on the interstellar medium by hot shells or powered by the momentum transferred by the SN/AGN photons to dust grains are thought to act differently in shaping the faint and the bright end of the galactic luminosity function. The impact of outflows on galaxy/IGM evolution depends strongly on the details of the coupling among the energy and the interstellar/intergalactic gas. Numerical studies at high resolution of the IGM and galactic feedback are under way but the results are not conclusive. However, some results allow significant constraints on the mass- load and energy transfer on both the hot and cold ISM, providing insights into the appropriate dynamical models of outflows and feedback that impact on the IGM properties out to large scales.
INAF Osservatorio Astronomico
via Tiepolo 11
I-34143 Trieste
Tel: +39 040 3199233
Fax: +39 040 3199241
email: viel(at)

JOB OPENING 2011 (2+1 yrs postdoctoral fellowship) -- CALL JOB OPENING 2011 (2+1 yrs postdoctoral fellowship) -- SUMMARY OF THE CALL

JOB OPENING 2012 (2+1 yrs postdoctoral fellowship) -- CALL DD 05/2012

JOB OPENING 2013 (2+1 yrs postdoctoral fellowship) -- CALL DD 03/2013

JOB OPENING 2013 (2 yrs postdoctoral fellowship) -- CALL DD 91/2013

JOB OPENING 2013 (2 yrs postdoctoral fellowship) -- SUMMARY OF THE CALL


The cosmoIGM team:

Dr. Matteo Viel

Dr. Paramita Barai

Dr. Francisco Villaescusa-Navarro

Dr. Tae-Sun Kim

Dr. Enea Di Dio

cosmoIGM Publications     Full List of COSMOIGM publications     Links
Lyman-alpha forest and cosmic weak lensing in a warm dark matter universe
Katarina Markovic, Matteo Viel
PREPRINT Accepted to PASA Review

Cosmic Degeneracies I: Joint N-body Simulations of Modified Gravity and Massive Neutrinos
Marco Baldi, Francisco Villaescusa-Navarro, Matteo Viel, Ewald Puchwein, Volker Springel, Lauro Moscardini
PREPRINT submitted

Cosmology with massive neutrinos III: the halo mass function and an application to galaxy clusters
Matteo Costanzi, Francisco Villaescusa-Navarro, Matteo Viel, Jun-Qing Xia, Stefano Borgani, Emanuele Castorina, Emiliano Sefusatti
PREPRINT submitted

Cosmology with massive neutrinos II: on the universality of the halo mass function and bias
E. Castorina, E. Sefusatti, R.K. Sheth, F. Villaescusa-Navarro, M. Viel
PREPRINT submitted

Cosmology with massive neutrinos I: towards a realistic modeling of the relation between matter, haloes and galaxies
Francisco Villaescusa-Navarro, Federico Marulli, Matteo Viel, Enzo Branchini, Emanuele Castorina, Emiliano Sefusatti, Shun Saito
PREPRINT submitted

Kinetic or thermal AGN feedback in simulations of isolated and merging disk galaxies calibrated by the M-sigma relation
Barai, Paramita; Viel, Matteo; Murante, Giuseppe; Gaspari, Massimo; Borgani, Stefano

Galactic winds in cosmological simulations of the circumgalactic medium
Barai, Paramita; Viel, Matteo; Borgani, Stefano; Tescari, Edoardo; Tornatore, Luca; Dolag, Klaus; Killedar, Madhura; Monaco, Pierluigi; D'Odorico, Valentina; Cristiani, Stefano
PREPRINT MNRAS (2013) 430 3213 .

Non-linear evolution of the cosmic neutrino background
Villaescusa-Navarro, Francisco; Bird, Simeon; Pena-Garay Carlos, Viel Matteo
PREPRINT JCAP (2013) 03 019 .

Constraining neutrino properties with a Euclid-like galaxy cluster survey
Costanzi Alunno Cerbolini, M.; Sartoris, B.; Xia, Jun-Qing; Biviano, A.; Borgani, S.; Viel, M.
PREPRINT JCAP (2013) 06 020

Scientific ones (archives, institutes & computing centers):

RTN network "The Physics of the IGM"
LUQAS sample
INAF Istituto Nazionale di Astrofisica
INFN Istituto Nazionale di Fisica Nucleare
Astronomy Department Trieste University
Dipartimento di Fisica Padova
MPA Garching - Germany
Institute of Astronomy Cambrige - UK
COSMOS supercomputer DAMTP, Cambridge - UK
Darwin Cluster High Performance Computer Service (HPCS) Cambridge - UK
CINECA SP6 (Italy) Cambridge - UK

Institute of Astronomy   Home   Publications