Related papers: Scale-dependent bias in the BAO-scale intergalacti…
The cross-section of sky occupied by a particular neutral hydrogen column density provides insight into the nature of Lyman-alpha absorption systems. We have measured this column density distribution at z=0 using 21-cm HI emission from a…
Intensity mapping of the neutral hydrogen brightness temperature promises to provide a three-dimensional view of the universe on very large scales. Nonlinear effects are typically thought to alter only the small-scale power, but we show how…
The next generation of spectroscopic surveys will target emission-line galaxies (ELGs) to produce constraints on cosmological parameters. We study the large scale structure traced by ELGs using a combination of a semi-analytical model of…
The Gunn-Peterson effect, absorption of Lya photons by a homogeneous component of the intergalactic medium (IGM), potentially provides a test of Big Bang Nucleosynthesis (BBN). With a lower limit on the UV radiation field estimated from the…
Recent work has suggested that, during reionisation, spatial variations in the ionising radiation field should produce enhanced Ly ${\alpha}$ forest transmission at distances of tens of comoving Mpc from high-redshift galaxies. We…
We present the first measurement of the large-scale cross-correlation of Lyman alpha forest absorption and Damped Lyman alpha systems (DLA), using the 9th Data Release of the Baryon Oscillation Spectroscopic Survey (BOSS). The…
We investigate the bias-dependence of the hybrid charge transfer state emission at planar heterojunctions between the metal oxide acceptor ZnO and three donor molecules. The electroluminescence peak energy linearly increases with the…
We study the three-dimensional distribution of non virialised matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydrodynamical simulations. We have collected the largest sample of QSO…
We compare cosmological hydrodynamical simulations combined with the homogeneous metagalactic UV background (UVB) of Haardt & Madau (2012) (HM2012) to observations of the Lyman-alpha forest that are sensitive to the thermal and ionization…
The intergalactic medium (IGM) prior to the epoch of reionization consists mostly of neutral hydrogen gas. Ly-alpha photons produced by early stars resonantly scatter off hydrogen atoms, causing energy exchange between the radiation field…
Large variations in the effective optical depth of the He II Ly$\alpha$ forest have been observed at $z\gtrsim2.7$, but the physical nature of these variations is uncertain: either the Universe is still undergoing the process of He II…
We investigate the spatial clustering of dark matter halos, collapsing from $1-4 \sigma$ fluctuations, in the redshift range $0 - 5$ using N-body simulations. The halo bias of high redshift halos ($z \geq 2$) is found to be strongly…
We have recently proposed a mechanism of photon-axion oscillations as a way of rendering supernovae dimmer without cosmic acceleration. Subsequently, it has been argued that the intergalactic plasma may interfere adversely with this…
We investigate the effect of primordial non-Gaussianity of the local f_NL type on the auto- and cross-power spectrum of dark matter haloes using simulations of the LCDM cosmology. We perform a series of large N-body simulations of both…
We describe a combined halo model to constrain the distribution of neutral hydrogen (HI) in the post-reionization universe. We combine constraints from the various probes of HI at different redshifts: the low-redshift 21-cm emission line…
We compute the 3D cross-correlation between the absorption of the $z\sim 2.3$ Lyman-alpha forest measured by the COSMOS Lyman-Alpha Mapping And Tomography Observations (CLAMATO) survey, and 1642 foreground galaxies with spectroscopic…
The history of the transition from a neutral intergalactic medium (IGM) to one that is almost fully ionized can reveal the character of cosmological ionizing sources. We study the evolution of the volume filling factor of HII and HeIII…
We examine the scale dependence of dark matter, halo and galaxy clustering on very large scales (0.01<k[h/Mpc]<0.15), due to non-linear effects from dynamics and halo bias. We pursue a two line offensive: high resolution numerical…
The observed large-scale scatter in Lyman $\alpha$ opacity of the intergalactic medium at $z<6$ implies large fluctuations in the neutral hydrogen fraction that are unexpected long after reionization has ended. A number of models have…
We characterize the baryon acoustic oscillations (BAO) feature in halo two-point statistics using N-body simulations. We find that nonlinear damping of the BAO signal is less severe for halos in the mass range we investigate than for dark…