Open AccessPhysical state of the intergalactic medium at redshifts z = 2–4
Author(s) -
Demiański M.,
Doroshkevich A. G.
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.1365-2966.2004.08179.x
Subject(s) - qsos , physics , redshift , quasar , astrophysics , intergalactic travel , background radiation , radiation , intergalactic medium , lyman alpha forest , astronomy , ultraviolet , galaxy , optics
We use two large surveys of quasars (QSOs), namely, 2QZ–6QZ and SDSS DR1, to estimate mean properties of the background ultraviolet (UV) radiation and the temperature of intergalactic gas at redshifts z ≈ 2–4 . We show that the intensity of the UV background radiation as estimated by Haardt & Madau (1996) should be increased by ∼20–30 per cent. We also briefly discuss spatial variations of both the intensity of background UV radiation and the gas temperature. These variations can be studied in more detail with high‐resolution observations of the proximity effects, Lyman α absorbers and metal systems. Using the minimal spanning tree technique, we analyse the spatial distribution of QSOs and show that it is quite similar to random (Poissonian).