High-Redshift Cosmography (2009)
Vitagliano, Vincenzo, Xia, Jun-Qing, Liberati, Stefano, Viel, Matteo
We constrain the parameters describing the kinematical state of the universe using a cosmographic approach, which is fundamental in that it requires a very minimal set of assumptions (namely to...
The impact of feedback on the low redshift Intergalactic Medium (2009)
Tornatore, Luca, Borgani, Stefano, Viel, Matteo, Springel, Volker
We analyse the evolution of the properties of the low-redshift Intergalactic Medium (IGM) using high-resolution hydrodynamic simulations that include a detailed chemical evolution model. We focus on...
Vallinotto, Alberto, Viel, Matteo, Das, Sudeep, Spergel, David N.
We expect a detectable correlation between two seemingly unrelated quantities: the four point function of the cosmic microwave background (CMB) and the amplitude of flux decrements in quasar (QSO)...
The rise of the C IV mass density at z (2009)
D'Odorico, Valentina, Calura, Francesco, Cristiani, Stefano, Viel, Matteo
The cosmic evolution of the metal content of the intergalactic medium puts stringent constraints on the properties of galactic outflows and on the nature of UV background. In this paper, we present a...
The High Redshift Integrated Sachs-Wolfe Effect (2009)
Xia, Jun-Qing, Viel, Matteo, Baccigalupi, Carlo, Matarrese, Sabino
In this paper we rely on the quasar (QSO) catalog of the Sloan Digital Sky Survey Data Release Six (SDSS DR6) of about one million photometrically selected QSOs to compute the Integrated Sachs-Wolfe...
Damped Lyman-alpha systems in high-resolution hydrodynamical simulations (2009)
Tescari, Edoardo, Viel, Matteo, Tornatore, Luca, Borgani, Stefano
We investigate the properties of Damped Lyman-alpha systems (DLAs) using high-resolution and large box-size cosmological hydrodynamical simulations of a LambdaCDM model. The numerical code used is a...
Lenses in the forest: cross-correlation of the Lyman-alpha flux with CMB lensing (2009)
Vallinotto, Alberto, Das, Sudeep, Spergel, David N., Viel, Matteo
We present a theoretical estimate for a new observable: the cross-correlation between the Lyman-alpha flux fluctuations in quasar (QSO) spectra and the convergence of the cosmic microwave background...
Early Dark Energy at High Redshifts: Status and Perspectives (2009)
Early dark energy models, for which the contribution to the dark energy density at high redshifts is not negligible, influence the growth of cosmic structures and could leave observable signatures...
Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
Previous fits of sterile neutrino dark matter models to cosmological data assumed a peculiar production mechanism, which is not representative of the best-motivated particle physics models given...
Realistic sterile neutrino dark matter with keV mass does not contradict cosmological bounds (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
Previous fits of sterile neutrino dark matter models to cosmological data assumed a peculiar production mechanism, which is not representative of the best-motivated particle physics models given...
Lyman-$\alpha$ constraints on warm and on warm-plus-cold dark matter models (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up...
Lyman-alpha constraints on warm and on warm-plus-cold dark matter models (2008)
Boyarsky, Alexey, Lesgourgues, Julien, Ruchayskiy, Oleg, Viel, Matteo
We revisit Lyman-alpha bounds on the dark matter mass in Lambda Warm Dark Matter (Lambda-WDM) models, and derive new bounds in the case of mixed Cold plus Warm models (Lambda-CWDM), using a set up...
Salucci, Paolo, Borgani, Stefano, Frenk, Carlos, Moscardini, Lauro, Viel, Matteo
In the study of the process of cosmic structure formation numerical simulations are crucial tools to interface observational data to theoretical models and to investigate issues otherwise unexplored....
The relation between Lyman-alpha absorbers and gas--rich galaxies in the local universe (2008)
Pierleoni, Marco, Branchini, Enzo, Viel, Matteo
We use high-resolution hydrodynamical simulations to investigate the spatial correlation between weak (N(HI)
Viel, Matteo, Becker, George D., Bolton, James S., Haehnelt, Martin G., Rauch, Michael, Sargent, Wallace L.
We present constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-alpha flux power spectrum of 55 high-resolution HIRES spectra at 2.0~5.6 keV (2sigma) for sterile...
On the importance of high redshift intergalactic voids (2008)
Viel, Matteo, Colberg, Joerg M., Kim, Tae-Sun
We investigate the properties of one--dimensional flux ``voids'' (connected regions in the flux distribution above the mean flux level) by comparing hydrodynamical simulations of large cosmological...
Viel, Matteo, Becker, George D., Bolton, James S., Haehnelt, Martin G., Rauch, Michael, Sargent, Wallace L. W.
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Cosmic dynamics in the era of Extremely Large Telescopes (2008)
Liske, Jochen, Grazian, Andrea, Vanzella, Eros, Dessauges, Miroslava, Viel, Matteo, Pasquini, Luca, ...
The redshifts of all cosmologically distant sources are expected to experience a small, systematic drift as a function of time due to the evolution of the Universe's expansion rate. A measurement of...
Is the Concentration of Dark Matter Halos at Virialization Universal ? (2007)
Ricotti, Massimo, Pontzen, Andrew, Viel, Matteo
Several recent studies suggest a correlation between dark matter halo mass and the shape of the density profile. We re-analyze simulations from Ricotti (2003) in which such a correlation was...
Strong MgII systems in quasar and gamma-ray burst spectra (2007)
Porciani, Cristiano, Viel, Matteo, Lilly, Simon J.
The incidence of strong MgII systems in gamma-ray burst (GRB) spectra is a few times higher than in quasar (QSO) spectra. We investigate several possible explanations for this effect, including: dust...
The CODEX-ESPRESSO experiment: cosmic dynamics, fundamental physics, planets and much more (2007)
Cristiani, Stefano, Avila, Gerardo, Bonifacio, Piercarlo, Bouchy, Francois, Carswell, B., D'Odorico, Sandro D., ...
CODEX, a high-resolution, super-stable spectrograph to be fed by the E-ELT, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the...
The CODEX-ESPRESSO experiment: cosmic dynamics, fundamental physics, planets and much more (2007)
Cristiani, Stefano, Avila, Gerardo, Bonifacio, Piercarlo, Bouchy, Francois, Carswell, B., D'Odorico, Sandro D., ...
CODEX, a high-resolution, super-stable spectrograph to be fed by the E-ELT, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the...
Numerical Simulations of the Lyman-alpha forest - A comparison of Gadget-2 and Enzo (2006)
Regan, John A., Haehnelt, Martin G., Viel, Matteo
We compare simulations of the Lyman-alpha forest performed with two different hydrodynamical codes, Gadget-2 and Enzo. A comparison of the dark matter power spectrum for simulations run with...
Can sterile neutrinos be ruled out as warm dark matter candidates? (2006)
Viel, Matteo, Lesgourgues, Julien, Haehnelt, Martin G., Matarrese, Sabino, Riotto, Antonio
We present constraints on the mass of warm dark matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the Sloan Digital Sky Survey \lya flux power spectrum at 2.2
The Lyman-alpha forest and WMAP year three (2006)
Viel, Matteo, Haehnelt, Martin G., Lewis, Antony
A combined analysis of Cosmic Microwave Background (CMB) and Lyman-a forest data allows to constrain the matter power spectrum from small scales of about 1 Mpc/h all the way to the horizon scale. The...
Expansion and Collapse in the Cosmic Web (2005)
Rauch, Michael, Becker, George D., Viel, Matteo, Sargent, Wallace L. W., Smette, Alain, Simcoe, Robert A., ...
We study the kinematics of the gaseous cosmic web at high redshift with Lyman alpha forest absorption in multiple QSO sightlines. Using a simple analytic model and a cosmological hydrodynamic...
Squeezing the window on isocurvature modes with the Lyman-alpha forest (2005)
Beltran, Maria, Garcia-Bellido, Juan, Lesgourgues, Julien, Viel, Matteo
Various recent studies proved that cosmological models with a significant contribution from cold dark matter isocurvature perturbations are still compatible with most recent data on cosmic microwave...
Spatial fluctuations in the spectral shape of the UV background at 2 (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Carswell, Robert F.
The low density hydrogen and helium in the IGM probed by QSO absorption lines is sensitive to the amplitude and spectral shape of the metagalactic UV background. We use realistic HI and HeII Ly-alpha...
Viel, Matteo, Haehnelt, Martin G.
(abridged) The flux power spectrum of the Lyman-alpha forest in quasar (QSO) absorption spectra is sensitive to a wide range of cosmological and astrophysical parameters and instrumental effects....
Viel, Matteo, Haehnelt, Martin G., Springel, Volker
We implement the hydro-PM (HPM) technique (Gnedin & Hui 1998) in the hydrodynamical simulation code GADGET-II and quantify the differences between this approximate method and full hydrodynamical...
The Lyman-alpha forest as a probe of fundamental physics (2005)
We use LUQAS, a sample of 27 high resolution high signal-to-noise UVES quasar (QSO) spectra (Kim et al. 2004), and the Croft et al. (2002) sample together with a set of high resolution large box size...
Constraints on the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Understanding the sources responsible for reionizing the Universe is a key goal of observational cosmology. A discrepancy has existed between the metagalactic hydrogen ionization rate, Gamma_HI,...
The Lyman alpha forest opacity and the metagalactic hydrogen ionization rate at z~ 2-4 (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Constraints on the meta-galactic hydrogen ionisation rate from the Lyman-α forest opacity (2005)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
CODEX : measuring the expansion of the universe (2005)
Pasquini, Luca, Cristiani, Stefano, Dekker, Hans, Haehnelt, Martin, Molaro, Paolo, Pepe, Francesco, ...
CODEX, a high-resolution, super-stable spectrograph to be fed by OWL, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the change of...
CODEX : measuring the expansion of the universe (2005)
Pasquini, Luca, Cristiani, Stefano, Dekker, Hans, Haehnelt, Martin, Molaro, Paolo, Pepe, Francesco, ...
CODEX, a high-resolution, super-stable spectrograph to be fed by OWL, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the change of...
CODEX : measuring the expansion of the universe (2005)
Pasquini, Luca, Cristiani, Stefano, Dekker, Hans, Haehnelt, Martin, Molaro, Paolo, Pepe, Francesco, ...
CODEX, a high-resolution, super-stable spectrograph to be fed by OWL, the most powerful telescope ever conceived, will for the first time provide the possibility of directly measuring the change of...
The Lyman-alpha forest opacity and the metagalactic hydrogen ionization rate at z~2-4 (2004)
Bolton, James S., Haehnelt, Martin G., Viel, Matteo, Springel, Volker
Estimates of the metagalactic hydrogen ionization rate from the Lyman-alpha forest opacity in QSO absorption spectra depend on the complex density distribution of neutral hydrogen along the...
Viel, Matteo, Weller, Jochen, Haehnelt, Martin
The combined analysis of the cosmic microwave background on large scales and Lyman-alpha forest on small scales provides a sufficiently long lever arm to obtain strong constraints on the slope and...
Viel, Matteo, Haehnelt, Martin G., Springel, Volker
We use the LUQAS sample (Kim et al. 2004), a set of 27 high-resolution and high signal-to-noise QSO absorption spectra at a median redshift of z=2.25, and the data from Croft et al. (2002) at a...
Cosmology with the lyman-alpha forest in the WMAP era (2003)
In the WMAP era of high precision cosmology an accuratedetermination of the matter power spectrum from lyman-alpha forest data becomescrucial. When combining the matter power spectrum derived from...
Cosmology with the lyman-alpha forest in the WMAP era (2003)
In the WMAP era of high precision cosmology an accuratedetermination of the matter power spectrum from lyman-alpha forest data becomescrucial. When combining the matter power spectrum derived from...
Cosmology with the lyman-alpha forest in the WMAP era (2003)
In the WMAP era of high precision cosmology an accurate determination of the matter power spectrum from lyman-alpha forest data becomes crucial. When combining the matter power spectrum derived from...
Cosmology with the lyman-alpha forest in the WMAP era (2003)
In the WMAP era of high precision cosmology an accuratedetermination of the matter power spectrum from lyman-alpha forest data becomescrucial. When combining the matter power spectrum derived from...
Cosmology with the lyman-alpha forest in the WMAP era (2003)
In the WMAP era of high precision cosmology an accuratedetermination of the matter power spectrum from lyman-alpha forest data becomescrucial. When combining the matter power spectrum derived from...
Galactic winds in the intergalactic medium (2002)
Theuns, Tom, Viel, Matteo, Kay, Scott, Schaye, Joop, Carswell, Robert F., Tzanavaris, Panayiotis
We have performed hydrodynamical simulations to investigate the effects of galactic winds on the high-redshift (z=3) universe. Strong winds suppress the formation of low-mass galaxies significantly,...