Molecular Hydrogen in high redshift Damped Lyman-α systems |
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| Authors: | Patrick Petitjean |
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| Institution: | (1) Institut d'Astrophysique de Paris, 98bis Boulevard Arago, 75014 Paris, France |
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| Abstract: | I describe briefly the status of an ongoing mini-survey for molecular hydrogen in high-redshift Damped Lyman-α systems using
UVES at the VLT. H2 is detected in about 30% of the cases. When H2 is not detected the molecular fraction f = 2N(H2)/(2N(H2)+N(HI) is smaller than 10-5. Therefore, most of the DLA systems arise in warm (T > 3000 K) and diffuse neutral gas embedded in a strong UV flux. The very recent detection of HD molecules in a Damped Lyman-α
system at z
abs = 2.337 demonstrates the possibility to discuss the high redshift chemistry.
This revised version was published online in September 2006 with corrections to the Cover Date. |
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| Keywords: | Observational cosmology Quasars Absorption lines Molecular hydrogen |
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