Related papers: Linking Ly-alpha and Low-Ionization Transitions at…

Spectra of high redshift QSOs show deep Gunn-Peterson absorptions on the blue sides of the \Lya emissions lines. They can be decomposed into components called \Lya leaks, defined to be emissive regions in complementary to otherwise…

Using the Space Telescope Imaging Spectrograph, we have obtained ultraviolet (UV) spectra from $\sim 1200$ to 2000 \AA\ of known Lyman continuum (LyC) emitting galaxies at low redshift ($z \sim 0.3-0.4$) with varying absolute LyC escape…

We present results from a spectroscopic and imaging survey of galaxies in the fields of quasars from the HST Quasar Absorption Line Key Project. The aim of this survey is to identify galaxies within 3.5' from the quasar sightline, to a…

We discuss the rest-frame optical emission line spectra of a large (~50) sample of z=3.1 Lyman alpha emitters (LAEs) whose physical properties suggest such sources are promising analogs of galaxies in the reionization era. Reliable Lyman…

We report the detection of Lyman Continuum (LyC) emission from the galaxy, CDFS-6664, at z=3.797 in a sample of Lyman break galaxies with detected [OIII] emission lines. The LyC emission is detected with a significance ~$5\sigma$ in the…

Galactic outflows are critical to our understanding of galaxy formation and evolution. However the details of the underlying feedback process remain unclear. We compare Ly$\alpha$ observations of the circumgalactic medium (CGM) of Lyman…

We present an analysis of HI Lyman-alpha emission in deep VLT/MUSE observations of two highly magnified and extended galaxies at z=3.5 and 4.03, including a newly discovered, almost complete Einstein ring. While these Lyman-alpha haloes are…

We report the spectroscopic confirmation of two Lyman break galaxies at redshift > 7. The galaxies were observed as part of an ultra-deep spectroscopic campaign with FORS2 at the ESO/VLT for the confirmation of z~7 ``z--band dropout''…

We investigate the radiative transfer of Lyman alpha photons through simplified anisotropic gas distributions, which represent physically motivated extensions of the popular 'shell-models'. Our study is motivated by the notion that (i)…

Most of the hydrogen in the intergalactic medium (IGM) was rapidly ionized at high-redshifts. While observations have established that reionization occurred, observational constraints on the emissivity of ionizing photons at high-redshift…

We present a study of the connection between the escape fraction of Lyman-alpha (Ly$\alpha$) and Lyman-continuum (LyC) photons within a sample of N=152 star-forming galaxies selected from the VANDELS survey at $3.85<z_{spec}<4.95$. By…

As part of a program to study the relationship between QSO Lyman alpha clouds and galaxies at low redshifts, we have obtained a high signal-to-noise far UV spectrum of H 1821+643 [z(em) = 0.297] with the G140L grating of the GHRS. The…

Assessing the contribution of ionizing sources to cosmic reionization is a central goal of extragalactic astrophysics. Understanding and quantifying ionizing escape remains challenging near the epoch of reionization. We present the…

The hydrogen Lyman-alpha (Lya) emission line, the brightest spectral feature of a photoionized gas, is considered an indirect tracer of the escape of Lyman continuum (LyC) photons, particularly when the intergalactic medium is too opaque…

We analyze rest-frame ultraviolet to optical spectra of three $z\simeq7.47$ - $7.75$ galaxies whose Ly$\alpha$-emission lines were previously detected with Keck/MOSFIRE observations, using the JWST/NIRSpec observations from the Cosmic…

We present the first results of a survey designed to understand the origin of the Lyman alpha-forest absorption systems at low redshift. Using the WYFFOS and HYDRA multi-fibre spectrographs on the WHT and WIYN telescopes, we have identified…

We present discovery spectra of a sample of eight lensed galaxies at high redshift, 3.7<z<5.2, selected by their red colors in the fields of four massive clusters: A1689, A2219, A2390, and AC114. Metal absorption lines are detected and…

We present Keck/MOSFIRE spectra of the diagnostic nebular emission lines [OIII]5007,4959, [OII]3727, and H-beta for a sample of 15 redshift z=3.1-3.7 Ly-alpha emitters (LAEs) and Lyman break galaxies (LBGs). In conjunction with spectra from…

The mechanisms of Ly$\alpha$ photon escape are key to understanding galaxy evolution and cosmic reionization, yet remain poorly understood. We investigate the UV-continuum sizes of 23 Ly$\alpha$ emitters (LAEs) at Cosmic Noon ($1.7 < z <…

The Hydrogen Lyman-alpha (Lya) line shows a large variety of shapes which is caused by factors at different scales, from the interstellar medium to the intergalactic medium. This work aims to provide a systematic inventory and…