Related papers: A Measurement of Small Scale Structure in the 2.2 …
The temperature of the low-density intergalactic medium is set by the balance between adiabatic cooling resulting from the expansion of the universe, and photo-heating by the UV-background. A sudden injection of entropy from the…
The observed scatter in intergalactic Lyman-$\alpha$ opacity at $z \lesssim 6$ requires large-scale fluctuations in the neutral fraction of the intergalactic medium (IGM) after the expected end of reionization. Post-reionization models that…
Many models of early structure formation predict a period of heating immediately preceding reionization, when X-rays raise the gas temperature above that of the cosmic microwave background. These X-rays are often assumed to heat the…
We briefly discuss the relevance of Lyman alpha forest observations for measuring cosmological parameters, comparing the properties of high z QSO spectra with those of artifical spectra from hydrodynamic simulations, based on hierarchical…
Previous studies of the 2.2 < z< 2.7 HeII Lyman-alpha forest measured much larger ionizing background fluctuations than are anticipated theoretically. We re-analyze recent Hubble Space Telescope data from the two HeII sightlines that have…
We introduce a new set of large scale, high resolution hydrodynamical simulations of the intergalactic medium: the Sherwood simulation suite. These are performed in volumes 10^3-160^3 h^-3 comoving Mpc^{3}, span almost four orders of…
(Abridged) Numerical simulations indicate that the intergalactic medium (IGM) responsible for the low column density Lyman-alpha forest follows a well defined temperature-density relation. We demonstrate that such an equation of state…
We discuss the origin and physical nature of the Lya forest absorption systems as found in hydrodynamical simulations of the Intergalactic Medium in a standard Cold Dark Matter cosmology (Omega=1, H0=50 km/s/Mpc, sigma_8=0.7). The…
Separating the cosmological redshifted 21-cm signal from foregrounds is a major challenge. We present the cross-correlation of the redshifted 21-cm emission from neutral hydrogen (HI) in the post-reionization era with the Ly-alpha forest as…
We investigate Lyman-alpha (Ly$\alpha$) transmission spikes at $5.2 < z < 6.8$ using synthetic quasar spectra from the ``Cosmic Reionization On Computers" simulations. We focus on understanding the relationship between these spikes and the…
The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter $\gamma$. We describe a new method to measure $\gamma$…
In the process of producing the roughly three ionizing photons per atom required to reionize the IGM, the same massive stars explode and eject metals into their surroundings. While the overly sensitive Lya transition makes Gunn-Peterson…
The Lyman alpha (Lya) forest in the spectra of z>5 quasars provides a powerful probe of the late stages of the Epoch of Reionization (EoR). With the recent advent of exquisite datasets such as XQR-30, many models have struggled to reproduce…
We examine the temperature structure of the intergalactic medium IGM) surounding a hard radiation source, such as a Quasi-Stellar Object (QSO), as it responds to the onset of helium reionization by the source. We model the reionization…
We explore how the assumption of ionization equilibrium modulates the modeled intergalactic medium (IGM) at the end of the hydrogen Epoch of Reionization using the cosmological radiation hydrodynamic \textsc{Technicolor Dawn} simulation. In…
Small-scale correlations measured in the Lyman-$\alpha$ (Ly$\alpha$) forest encode information about the intergalactic medium and the primordial matter power spectrum. In this article, we present and implement a simple method to measure the…
I review results obtained from studies of the high-redshift Lyman alpha forest, and present new results from HST/STIS spectra of low-redshift quasars in comparison with cosmological hydrodynamic simulations. The evolution of the Lyman alpha…
We compare a sample of five high-resolution, high S/N Ly$\alpha$ forest spectra of bright $6<z \lesssim 6.5$ QSOs aimed at spectrally resolving the last remaining transmission spikes at $z>5$ with those obtained from mock absorption spectra…
During the epoch of reionization a large number of photons were produced with frequencies below the hydrogen Lyman limit. After redshifting into the closest resonance, these photons underwent multiple scatterings with atoms. We examine the…
We investigate correlations between the long wavelength fluctuations and the small scale power in the Lyman alpha forest. We show that such correlations can be used to discriminate between fluctuations induced by large scale structure and…