Related papers: Mapping quasar light echoes in 3D with Ly{\alpha} …
Insight into quasar ages may be obtained from the proximity effect, but so far only in a limited number of bright quasars. Based on ~2600 SDSS quasar spectra at 2.5 <= z <= 3.5, a search for spectral voids between Ly-alpha forest lines…
The impact of cosmic reionization on the Ly$\alpha$ forest power spectrum has recently been shown to be significant even at low redshifts ($z \sim 2$). This memory of reionization survives cosmological time scales because high-entropy…
We directly measure the evolution of the intergalactic Lyman-alpha effective optical depth, tau_eff, over the redshift range 2<z<4.2 from a sample of 86 high-resolution, high-signal-to-noise quasar spectra obtained with Keck/ESI,…
In Paper III of our series "A Uniform Analysis of the Ly-alpha forest at z=0 - 5", we presented a set of 270 quasar spectra from the archives of the Faint Object Spectrograph on the Hubble Space Telescope. A total of 151 of these spectra,…
The conditions within the ionization front of a quasar during reionization (T ~ 30,000 K, neutral hydrogen fraction ~ 0.5) are ideal for producing Lyman-alpha emission via collisional excitation of hydrogen atoms. Observations of this…
We have carried out deep and wide field imaging observations with narrow bands targeting 11 quasar fields to systematically study the possible photoevaporation effect of quasar radiation on surrounding low mass galaxies at $z\sim2-3$. We…
Ionizing sources embedded in the neutral intergalactic medium (IGM) before cosmological reionization generate discrete HII regions. We show that a sufficiently bright quasar (for example, one tenth as luminous as that recently discovered by…
A bright quasar residing in a dense and largely neutral intergalactic medium (IGM) at high redshifts (z > 6) will be surrounded by a large cosmological Stromgren sphere. The quasar's spectrum will then show a sharp increase in resonant…
The z > 2 Lyman-alpha (Lya) forest traces the underlying dark-matter distribution on large scales and, given sufficient sightlines, can be used to create 3D maps of large-scale structure. We examine the observational requirements to…
The Lyman-$\alpha$ (hereafter Ly-$\alpha$) forest is a probe of large-scale matter density fluctuations at high redshift, $z > 2.1$. It consists of HI absorption spectra along individual lines-of-sight. If the line-of-sight density is large…
We explore the requirements for a Lyman-alpha forest (LyaF) survey designed to measure the angular diameter distance and Hubble parameter at 2~<z~<4 using the standard ruler provided by baryonic acoustic oscillations (BAO). The goal would…
The intergalactic neutral hydrogen which is responsible for the Lyman alpha forest of quasar absorption is a tracer of much larger amounts of ionised hydrogen. The ionised component has yet to be detected directly, but is expected to…
The 21-cm forest is a promising probe of the Epoch of Reionization. The local state of the intergalactic medium (IGM) is encoded in the spectrum of a background source (radio-loud quasars or gamma ray burst afterglow) by absorption at the…
Since the discovery of $z\sim 6$ quasars two decades ago, studies of their Ly$\alpha$-transparent proximity zones have largely focused on their utility as a probe of cosmic reionization. But even when in a highly ionized intergalactic…
In this Letter we explore a version of the test of cosmological geometry proposed by Alcock and Paczynski (1979), using observations of the Lyman-alpha forest in the spectra of close quasar pairs. By comparing the correlations in absorption…
We report new measurements of the intergalactic medium (IGM) Ly$\alpha$ and Ly$\beta$ effective optical depth at $5.3<z<6.5$, using a new sample of quasar sightlines including 32 quasars at $6.308\le z\le7.00$. These quasars provide a large…
In this work, we explore the application of intensity mapping to detect extended Ly$\alpha$ emission from the IGM via cross-correlation of PAUS images with Ly$\alpha$ forest data from eBOSS and DESI. Seven narrow-band (FWHM=13nm) PAUS…
We analyse the proximity zone of the intergalactic matter around high-redshift quasars in a cosmological environment. In a box of 64 h-1 Mpc base length we employ dark matter only simulations. For estimating the hydrogen temperature and…
Mapping of the large-scale structure through cosmic time has numerous applications in the studies of cosmology and galaxy evolution. At $z > 2$, the structure can be traced by the neutral intergalactic medium (IGM) by way of observing the…
The large opacity fluctuations in the $z > 5.5$ Ly$\alpha$ forest may indicate inhomogeneous progress of reionization. To explain the observed large scatter of the effective Ly$\alpha$ optical depth ($\tau_{\rm eff}$) of the intergalactic…