Related papers: On the correlation between Ly$\alpha$ forest opaci…
We study the spatial fluctuations in the hydrogen ionizing background in the epoch following reionization (z ~ 5--6). The rapid decrease with redshift in the photon mean free path (m.f.p.), combined with the clustering of increasingly rare…
Lyman alpha absorber correlations contain information about the underlying density distribution associated with a particular class of absorbers. As such, they provide an opportunity to independently measure the "bias" of the Lyman alpha…
We present predictions of the correlation between the Lyman-alpha forest absorption in quasar spectra and the mass within \sim 5 Mpc/h (comoving) of the line of sight, using fully hydrodynamic and hydro-PM numerical simulations of the cold…
Local variations in the intergalactic medium (IGM) neutral hydrogen fraction will affect the Ly-$\alpha$ absorption signature of protoclusters identified in tomographic surveys. Using the IllustrisTNG simulations, we investigate how the AGN…
The quasar in the Hubble Deep Field South (HDFS), J2233-606 (z=2.23) has been exhaustively observed by ground based telescopes and by the STIS spectrograph on board the Hubble Space Telescope at low, medium and high resolution in the…
Cross-correlations between 21cm observations and galaxy surveys provide a powerful probe of reionization by reducing foreground sensitivity while linking ionization morphology to galaxies. We quantify the constraining power of 21cm-Galaxy…
We investigate the cosmic reionization history by comparing semi-analytical models of the Lya forest with observations of high-z quasars and gamma ray bursts absorption spectra. In order to constrain the reionization epoch z_rei, we…
We show that the Lyman-alpha optical depth statistics in the proximity regions of quasar spectra depend on the mass of the dark matter halos hosting the quasars. This is owing to both the overdensity around the quasars and the associated…
We publicly release a new sample of $34$ medium resolution quasar spectra at $5.77\leq z_{\rm em}\leq6.54$ observed with the Echellette Spectrograph and Imager (ESI) on the Keck telescope. This quasar sample represents an ideal laboratory…
Recent work has shown that the z~2.5 Lyman-alpha forest on large scales encodes information about the galaxy and quasar populations that keep the intergalactic medium photoionized. We present the first forecasts for constraining the…
The gravitationally lensed quasar J014516.6-094517 at z=2.719 has been observed with the ESPRESSO instrument at the ESO VLT to obtain high-fidelity spectra of the two images A and B with a resolving power R=70000. At the redshifts under…
We investigate the properties of the Lyman alpha forest as predicted by numerical simulations for a range of currently viable cosmological models. This is done in order to understand the dependencies of the forest on cosmological…
The forest of Lyman-alpha absorption lines seen in the spectra of distant quasars has become an important probe of the distribution of matter in the Universe. We use large, hydrodynamical simulations from the OWLS project to investigate the…
We present a statistical analysis of Ly$\alpha$ absorption using 581 galaxies at $z=4.5$--13 observed with multiple JWST/NIRSpec spectroscopy programs, including JADES, UNCOVER, CEERS, and GO/DDT. We carefully construct composite spectra…
The spatial distribution of Ly-alpha forest absorption systems towards ten QSOs has been analysed to search for large-scale structure over the redshift range 2.2 < z < 3.4. The QSOs form a closely spaced group on the sky and are…
We explore possibility of using the three dimensional bispectra of the Ly-alpha forest and the redshifted 21-cm signal from the post-reionization epoch to constrain primordial non-Gaussianity. Both these fields map out the large scale…
Lyman-alpha (Ly$\alpha$) emission from galaxies can be used to trace neutral hydrogen in the epoch of reionization, however, there is a degeneracy between the attenuation of Ly$\alpha$ in the intergalactic medium (IGM) and the line profile…
We examine the evolution of the IGM Ly-alpha optical depth distribution using the transmitted flux probability distribution function (PDF) in a sample of 63 QSOs spanning absorption redshifts 1.7 < z < 5.8. The data are compared to two…
We present the analysis of deep HST multi-band imaging of the BDF field specifically designed to identify faint companions around two of the few Ly-alpha emitting galaxies spectroscopically confirmed at z~7 (Vanzella et al. 2011). Although…
The Ly$\alpha$ line is an important diagnostic for star formation at high redshift, but interpreting its flux and line profile is difficult because of the resonance nature of Ly$\alpha$. Trends between the escape of Ly$\alpha$ photons and…