相关论文: The Proximity Effect Around High Redshift Galaxies
In order to assess the contribution of Lyman break galaxies (LBGs) and Lyman alpha emitters (LAEs) at redshifts 3<z<7 to the ionization of intergalactic medium (IGM), we investigate the escape fractions of ionizing photons from…
One of the key questions in observational cosmology is the identification of the sources responsible for ionisation of the Universe after the cosmic Dark Ages, when the baryonic matter was neutral. The currently identified distant galaxies…
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…
We present a comprehensive analysis of the relationship between galaxies and the intergalactic medium (IGM) during the late stages of cosmic reionization, based on the complete JWST EIGER dataset. Using deep NIRCam $3.5\,\mathrm{\mu m}$…
We have obtained deep Hubble Space Telescope far-UV images of 15 starburst galaxies at z~1.3 in the GOODS fields to search for escaping Lyman continuum photons. These are the deepest far-UV images m_{AB}=28.7, 3\sigma, 1" diameter) over…
We develop a new method to determine the distance between a high-redshift galaxy and a foreground screen of atomic hydrogen. In a partially neutral universe, and assuming spherical symmetry, this equates to the radius of a ionized 'bubble'…
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…
Constraining when and how reionisation began is pivotal for understanding when the first galaxies formed. Lyman-alpha (Ly$\alpha$) emission from galaxies is currently our most promising probe of these early stages. At z>7 the majority of…
Theoretical and observational arguments suggest that the intergalactic medium (IGM) might have been polluted with metals produced by early star formation. In this scenario, Lyman-break galaxies (LBGs) at redshift z=3 are likely to be…
Potential contamination from low/intermediate-redshift galaxies, such as objects with a prominent Balmer break, affects the photometric selection of high-redshift galaxies through identification of a Lyman break. Traditionally,…
We investigate Lyman-alpha (Ly$\alpha$) transmission spikes at $5.2 < z < 6.8$ using synthetic quasar spectra from the ``Cosmic Reionization On Computers" simulations. We focus on understanding the relationship between these spikes and the…
We present a Bayesian inference on the neutral hydrogen fraction of the intergalactic medium (IGM), $x_{\textrm{HI}}$, at $z \sim$ 6-8 using the properties of Lyman break galaxies during the Epoch of Reionization. We use large samples of…
The estimate of the ionizing UV background through the proximity effect analysis is discussed. Taking into account the correct bending of the column density distribution which appears in high resolution high s/n data, a value of the UV…
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…
We present the first simulations of the high-redshift Ly$\alpha$ intensity field that account for scattering in the intergalactic medium (IGM). Using a 3D Monte Carlo radiative transfer code, we find that Ly$\alpha$ scattering smooths…
The selection of high redshift sources from broad-band photometry using the Lyman-break galaxy (LBG) technique is a well established methodology, but the characterization of its contamination for the faintest sources is still incomplete. We…
We investigate the relationship between the Lyman-alpha (Lya) forest transmission in the intergalactic medium (IGM) and the environmental density of galaxies, focusing on its implications for the measurement of ionizing radiation escape…
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…
We investigate the intrinsic opacity of high-redshift galaxies to outgoing ionising photons using high-quality photometry of a sample of 27 spectroscopically-identified galaxies of redshift 1.9<z<3.5 in the Hubble Deep Field. Our…
We have studied the effects of gas density inhomogeneities on the escape of ionising Lyman continuum (Lyc) photons from Milky Way-type galaxies via 3D numerical simulations using the Monte Carlo radiative transfer code CRASH (Ciardi et al.…