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Query : 2011MNRAS.410.2193M |
2011MNRAS.410.2193M - Mon. Not. R. Astron. Soc., 410, 2193-2202 (2011/February-1)
Revisiting the He II to H I ratio in the intergalactic medium.
MUZAHID S., SRIANAND R. and PETITJEAN P.
Abstract (from CDS):
We show that, if we constrain the fit of the H I and/or He II absorption profiles with the presence of metal components, we can accommodate η values in the range 15-100 in these systems, assuming that broadening is intermediate between pure thermal and pure turbulent.
While simple photoionization models reproduce the observed N(O VI)/N(C IV) ratio, they fail to produce low η values, in contrast to models with high temperatures (i.e T ≥ 105 K). The Doppler parameters measured for different species suggest a multiphase nature of the absorbing regions. Therefore, if low η values were to be confirmed, we would favour a multiphase model in which most of the gas is at a high temperature (>105 K) but the metals, and in particular C IV, are due to a lower-temperature ( ∼ few 104 K) photoionized gas.
Abstract Copyright: 2010 The Authors. Journal compilation2010 RAS
Journal keyword(s): intergalactic medium - quasars: absorption lines - quasars: individual: HE 2347-4342
Simbad objects: 2
Number of rows : 2 |
N | Identifier | Otype |
ICRS (J2000) RA |
ICRS (J2000) DEC |
Mag U | Mag B | Mag V | Mag R | Mag I | Sp type |
#ref
1850 - 2024 |
#notes |
---|---|---|---|---|---|---|---|---|---|---|---|---|
1 | QSO J2349-4338 | QSO | 23 49 34.5381699648 | -43 38 08.687827860 | 20.21 | ~ | 4 | 0 | ||||
2 | QSO B2347-4342 | QSO | 23 50 34.2593744544 | -43 25 59.683985652 | 16.3 | 16.3 | ~ | 170 | 0 |
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