Related papers: The Wouthuysen-Field effect in a clumpy intergalac…
We show that a new interference effect appears in the intensity fluctuations of photons multiply scattered by an atomic gas of large optical depth b. This interference occurs only for scattering atoms that are Zeeman degenerate and it leads…
Spectra from the Keck HIRES instrument of the Lyman alpha forests in the lines of sight to the A and C components of the gravitationally lensed QSO Q1422+231 were used to investigate the structure of the intergalactic medium at mean…
There has been great progress in recent years in discovering star forming galaxies at high redshifts (z>5), close to the epoch of reionization of the intergalactic medium (IGM). The WFC3 and ACS cameras on the Hubble Space Telescope have…
We report a new way to slow down the spontaneous emission rate of excitons in the wetting layer (WL) through radiative field coupling between the exciton emissions and the dipole field of metal islands. As a result, a long-lifetime decay…
For a source of Ly alpha radiation embedded in a neutral intergalactic medium (IGM) prior to the reionization epoch, the emission line is strongly suppressed by the intervening IGM. The damping wing of the so-called Gunn-Peterson trough can…
Radio continuum emission provides a unique opportunity to study star-formation unbiased by dust obscuration. However, if radio observations are to be used to accurately trace star-formation to high redshifts, it is crucial that the physical…
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. We have analysed the Lyman-alpha forest of eleven…
We calculate the absolute intensity and anisotropies of the Lyman-alpha radiation field present during the epoch of reionization. We consider emission from both galaxies and the intergalactic medium (IGM) and take into account the main…
Lyman-Alpha (Ly$\alpha$) is the strongest emission line in the Universe and is frequently used to detect and study the most distant galaxies. Because Lya is a resonant line, photons typically scatter prior to escaping; this scattering…
During the epoch of reionisation the first galaxies were enshrouded in pristine neutral gas, with one of the brightest emission lines in star-forming galaxies, Lyman-$\alpha$ (Ly$\alpha$), expected to remain undetected until the Universe…
The fraction of galaxies with strong Ly$\alpha$ emission has been observed to decrease rapidly with redshift at $z \ge 6$, after a gradual increase at $z< 6$. This has been interpreted as a hint of the reionization of the intergalactic…
This work investigates single-photon scattering in a one-dimensional coupled-resonator waveguide coupled to a giant atom with a complex on-site energy. Within the generalized projection operator formalism, we derive analytical expressions…
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…
The escape of cosmic rays from the Galaxy is expected to shape their spectrum inside the Galaxy. Yet, this phenomenon is very poorly understood and, in the absence of a physical description, it is usually modelled as free escape from a…
We perform a systematic study of how the inhomogeneities in the Inter-Galactic Medium (IGM) affect the observability of Lyman Alpha Emitters (LAEs) around the Epoch of Reionization. We focus on the IGM close to the galaxies as the detailed…
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, predicted by early hydrodynamical simulations…
High-resolution hydrodynamics simulations of the Ly-alpha forest in cold dark matter dominated cosmologies appear to predict line widths that are substantially narrower than those observed. Here we point out that Compton heating of the…
Small-scale density fluctuations can significantly affect reionization but are typically modelled quite crudely. Unresolved fluctuations in numerical simulations and analytical calculations are included using a gas clumping factor,…
If enough of their Lyman limit continuum escapes, star-forming galaxies could be significant contributors to the cosmic background of ionizing photons. To investigate this possibility, we obtained the first deep imaging in the far…
We investigate the single-photon scattering spectra of a giant atom coupled to a one dimensional waveguide via multiple connection points or a continuous coupling region. Using a full quantum mechanical method, we obtain the general…