The Proximity Effect Around High Redshift Galaxies

Abstract

Recent observations have shown that the intergalactic medium (IGM) is more transparent to Lyalpha photons close to Lyman Break Galaxies (LBGs) than at large distance from them, ie a proximity effect. Cosmological simulations including winds from LBGs have been so far unable to explain this trend. By coupling such simulations with the radiative transfer code CRASH, we investigate whether the addition of the ionizing radiation emitted by LBGs can increase the transmissivity by decreasing the neutral hydrogen fraction in the inner Mpc of the galaxy halo. The transmissivity as a function of distance is roughly reproduced only if LBGs are identified with dwarf galaxies (with masses < 10^9 solar masses), which are undergoing a vigorous (50 solar masses/yr) burst of star formation. Similar star formation rates in larger galaxies are not sufficient to overwhelm the large recombination rates associated with their denser environment. If so, photoionization partly reconciles theory with observations, although we discuss a number of uncertainties affecting both approaches.

5 pages, 3 figures, submitted to MNRAS

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Cited by in corpus (11)

• The Connection Between Galaxies and Intergalactic Absorption Lines at Redshift 2<z<3
• Physical effects on the Lyman-alpha forest flux power spectrum: damping wings, ionizing radiation fluctuations, and galactic winds
• Ionizing radiation fluctuations and large-scale structure in the Lyman-alpha forest
• IGM metal enrichment through dust sputtering
• Radiative Transfer Effects on the Lya Forest
• The density structure around quasars from optical depth statistics
• Absorption features of high redshift galactic winds
• X-ray ionization of the intergalactic medium by quasars
• Quasars as probes of cosmological reionization
• The impact of galactic winds from LBGs on the Intergalactic Medium
• Radiative transfer of ionizing radiation through gas and dust: grain charging in star forming regions