A carbon-enhanced metal-poor damped Ly alpha system: probing gas from Population III nucleosynthesis?

作者：Cooke Ryan^*; Pettini Max; Steidel Charles C; Rudie Gwen C; Jorgenson Regina A

来源：Monthly Notices of the Royal Astronomical Society, 2011, 412(2): 1047-1058.

DOI：10.1111/j.1365-2966.2010.17966.x

• stars: carbon
• stars: Population III
• galaxies: abundances
• galaxies: evolution
• quasars: absorption lines
• quasars: individual: J0035-0918

We present high-resolution observations of an extremely metal-poor damped Ly alpha system (DLA), at z(abs) = 2.340 0972 in the spectrum of the QSO J0035-0918, exhibiting an abundance pattern consistent with model predictions for the supernova yields of Population III stars. Specifically, this DLA has [Fe/H] similar or equal to -3, shows a clear 'odd-even' effect, and is C-rich with [C/Fe] = +1.53, a factor of similar to 20 greater than reported in any other DLA. In analogy to the carbon-enhanced metal-poor stars in the Galactic halo (with [C/Fe] > +1.0), this is the first known case of a carbon-enhanced DLA. We determine an upper limit to the mass of 12C, M(12C) < 200 M-circle dot, which depends on the unknown gas density n(H); if n(H) > 1 cm-3 (which is quite likely for this DLA given its low velocity dispersion), then M(12C) < 2 M-circle dot, consistent with pollution by only a few prior supernovae. We speculate that DLAs such as the one discovered here may represent the 'missing link' between the yields of Population III stars and their later incorporation in the class of carbon-enhanced metal-poor stars which show no enhancement of neutron-capture elements (CEMP-no stars).

• 出版日期2011-4