Open AccessThe escape fraction of ionizing photons from galaxies at z = 0–6
Author(s) -
Inoue Akio K.,
Iwata Ikuru,
Deharveng JeanMichel
Publication year - 2006
Publication title -
monthly notices of the royal astronomical society: letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.067
H-Index - 122
eISSN - 1745-3933
pISSN - 1745-3925
DOI - 10.1111/j.1745-3933.2006.00195.x
Subject(s) - physics , ionizing radiation , reionization , astrophysics , intergalactic travel , redshift , galaxy , photon , rest frame , flux (metallurgy) , cosmic ray , absorption (acoustics) , astronomy , irradiation , nuclear physics , optics , materials science , metallurgy
ABSTRACT The escape fraction of ionizing photons from galaxies is a crucial quantity controlling the cosmic ionizing background radiation and the reionization. Various estimates of this parameter can be obtained in the redshift range z = 0–6, either from direct observations or from the observed ionizing background intensities. We compare them homogeneously in terms of the observed flux density ratio of ionizing (∼900 Å rest‐frame) to non‐ionizing ultraviolet (∼1500 Å rest‐frame) corrected for the intergalactic absorption. The escape fraction is found to increase by an order of magnitude, from a value less than 0.01 at z ≲ 1 to about 0.1 at z ≳ 4 .