Related papers: Quasar Ionization Front Ly{\alpha} Emission in an …
We analyze the Ly alpha forest properties of a sample of 15 high redshift quasars lying between z = 4.42 and z = 5.75, using high signal-to-noise spectra obtained with ESI on the Keck II 10 m telescope. The distribution of transmissions in…
We present long-slit spectroscopic data which reveals extended Lyman alpha emission around the z=6.417 radio-quiet quasar CFHQS J2329-0301. The Lyman alpha emission is extended over 15 kpc and has a luminosity of > 8 x 10^36 W, comparable…
Using radiative transfer calculations and cosmological simulations of structure formation, we study constraints that can be placed on the nature of the cosmic ultraviolet (UV) background in the redshift interval 2.5< z <5. Our approach…
Mapping the intergalactic medium (IGM) in Lyman-$\alpha$ emission would yield unprecedented tomographic information on the large-scale distribution of baryons and potentially provide new constraints on the UV background and various feedback…
Arguably the best hope of understanding the tail end of the reionization of the intergalactic medium (IGM) at redshift z > 6 is through the detection and characterization of the Gunn-Peterson (GP) damping wing absorption of the IGM in…
The shape of the Ly-$\alpha$ transmission in the near zone of the redshift $z=5.9896$ quasar ULAS J0148$+$0600 (hereafter J0148) is consistent with a damping wing arising from an extended neutral hydrogen island in the diffuse intergalactic…
We study the formation of a partially ionized zone behind the usual H II zone in photo-ionized gas for gas density intermediate between ordinary H II regions and AGN BLRs and without X-rays. While Lyman continuum photons are depleted before…
We build a physical model for high-redshift Lyman Alpha emitters (LAEs) by coupling state of the art cosmological simulations (GADGET-2) with a dust model and a radiative transfer code (pCRASH). We post-process the cosmological simulation…
We present new simulations of Lyman-$\alpha$ (Ly$\alpha$) intensity maps that include Ly$\alpha$ radiative transfer in the intergalactic medium (IGM) and all significant sources of Ly$\alpha$ photons. The sources considered include…
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…
We investigate the thermal and ionization history of Lyman alpha clouds photoionized by a time--dependent UV background, including non equilibrium effects. The results show that it is possible to obtain temperatures as low as T~15000 K (or,…
The observability of Lyman-alpha emitting galaxies (LAEs) during the Epoch of Reionization can provide a sensitive probe of the evolving neutral hydrogen gas distribution, thus setting valuable constraints to distinguish different…
We investigate the detectability of Lyman-$\alpha$ (Ly$\alpha$) emission from galaxies at the onset of cosmic reionization, aiming to understand the conditions necessary for detecting high-redshift sources like JADES-GS-z13-1-LA at $z=13$.…
We present measurements of the mean and scatter of the IGM Lyman-{\alpha} opacity at 4.9 < z < 6.1 along the lines of sight of 62 quasars at z > 5.7, the largest sample assembled at these redshifts to date by a factor of two. The sample…
Following the completion of cosmic reionization, the mean-free-path of ionizing photons was set by a population of Ly-limit absorbers. As the mean-free-path steadily grew, the intensity of the ionizing background also grew, thus lowering…
High-redshift QSO spectra show large spatial fluctuations in the Ly-alpha opacity of the intergalactic medium on surprisingly large scales at z>~5.5. We present a radiative transfer simulation of cosmic reionization driven by galaxies that…
The reionization of helium is thought to occur at $2.5\lesssim z\lesssim4$, marking the last phase transition and final global heating event of the intergalactic medium (IGM). Since it is driven by rare quasars, helium reionization should…
We have discovered extended Lyman-$\alpha$ emission around a $z=4.5$ QSO in a deep long-slit spectrum with Keck/LRIS at moderate spectral resolution ($R\approx 1000$). The line emission extends 5\,arcsec beyond the continuum of the QSO and…
It is generally taken for granted that reionization has completed by z=6, due to the detection of flux in the Lyman alpha forest at redshifts z<6. However, since reionization is expected to be highly inhomogeneous, much of the spectra pass…
We present a new, high resolution HST/GHRS spectrum of quasar Q0302-003, and use the HeII Lyman-$\alpha$ absorption, together with a high resolution Keck spectrum of the HI Lyman-$\alpha$ forest, to probe the distribution and ionization…