Query : 2011A&A...534A..82F

2011A&A...534A..82F - Astronomy and Astrophysics, volume 534A, 82-82 (2011/10-1)

High-ion absorption in the proximate damped Ly-α system toward Q0841+129.


Abstract (from CDS):

We present VLT/UVES spectroscopy of the quasar Q0841+129, whose spectrum shows a proximate damped Ly-α (PDLA) absorber at z=2.47621 and a proximate sub-DLA at z=2.50620, both lying close in redshift to the QSO itself at zem=2.49510±0.00003. This fortuitous arrangement, with the sub-DLA acting as a filter that hardens the QSO's ionizing radiation field, allows us to model the ionization level in the foreground PDLA, and provides an interesting case-study on the origin of the high-ion absorption lines SiIV, CIV, and OVI in DLAs. The high ions in the PDLA show at least five components spanning a total velocity extent of ≃160km/s, whereas the low ions exist predominantly in a single component spanning just 30km/s. We examine various models for the origin of the high ions. Both photoionization and turbulent mixing layer models are fairly successful at reproducing the observed ionic ratios after correcting for the non-solar relative abundance pattern, though neither model can explain all five components. We show that the turbulent mixing layer model, in which the high ions trace the interfaces between the cool PDLA gas and a hotter phase of shock-heated plasma, can explain the average high-ion ratios measured in a larger sample of 12 DLAs.

Abstract Copyright:

Journal keyword(s): quasars: absorption lines - galaxies: high-redshift - galaxies: halos - galaxies: ISM

Simbad objects: 4

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Number of rows : 4
N Identifier Otype ICRS (J2000)
ICRS (J2000)
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2023
1 QSO B0841+129 BLL 08 44 24.2445546984 +12 45 46.526286780   18.28 18.5     ~ 116 0
2 QSO J1211+0422 QSO 12 11 17.5953013200 +04 22 22.290863808   18.35 18.13     ~ 47 0
3 LBQS 2206-1958A QSO 22 08 52.0729138920 -19 43 59.866776948   17.49 17.33     ~ 214 0
4 QSO B2206-1959 QSO 22 09 00.6950774976 -19 44 19.743416484     18.65     ~ 83 0

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