Open AccessThe proximity effect around high‐redshift galaxies
Author(s) -
Maselli A.,
Ferrara A.,
Bruscoli M.,
Marri S.,
Schneider R.
Publication year - 2004
Publication title -
monthly notices of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.058
H-Index - 383
eISSN - 1365-2966
pISSN - 0035-8711
DOI - 10.1111/j.1365-2966.2004.07810.x
Subject(s) - physics , astrophysics , galaxy , redshift , dwarf galaxy , radiative transfer , star formation , halo , photoionization , intergalactic medium , astronomy , reionization , ionization , ion , quantum mechanics
Recent observations have shown that the intergalactic medium (IGM) is more transparent to Lyα photons close to Lyman break galaxies (LBGs) than at large distance from them, i.e. there is 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 M ⊙ ) which are undergoing a vigorous (50 M ⊙ yr −1 ) 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.