NOAO >   Observing Info >   Approved Programs >   2011A-0060

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Proposal Information for 2011A-0060


PI: Max Pettini, University of Cambridge, pettini@ast.cam.ac.uk
Address: Institute of Astronomy, Madingley Road, Cambridge CB3 0HA, UK

CoI: Ryan Cooke, Institute of Astronomy

Title: A Search for Carbon-Enhanced Metal-Poor DLAs: Probing Population III Nucleosynthesis

Abstract: High redshift damped Lyman alpha systems (DLAs) with metallicities less than 1/100 of solar are near-ideal environments for probing the nucleosynthesis by some of the first structures to form in the Universe. As part of our on-going studies of metal-poor DLAs, we recently discovered a DLA that: has an Fe abundance 1/1000 of solar, exhibits a clear `odd-even' effect, and is carbon-rich with a C/Fe ratio 35 times greater than solar. All these characteristics are consistent with nucleosynthesis by metal-free (Population III) stars, and have so far only been seen in `Carbon-Enhanced Metal-Poor' (CEMP) stars, a class of halo stars which includes the three most Fe-poor stars known to date. Motivated by this important discovery, we now propose to enlarge the still meagre sample of very metal-poor DLAs with intermediate resolution spectroscopy of candidates selected from the SDSS. The spectra sought will: (i) measure the column density of H \sc i; (ii) provide an approximate measure of the metallicity via weak Fe \sc ii lines; and (iii) identify the most promising candidate CEMP-DLAs for future targeted observations with echelle spectrographs.


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NOAO >   Observing Info >   Approved Programs >   2011A-0060

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