The explosion energy of early stellar populations: the Fe-peak element ratios in low-metallicity damped Lyα systems
Abstract
The relative abundances of the Fe-peak elements (Ti–Zn) at the lowest metallicities are intimately linked to the physics of core-collapse supernova explosions. With a sample of 25 very metal poor damped Lyα systems (DLAs), we investigate the trends of the Fe-peak element ratios with metallicity. For nine of the 25 DLAs, a direct measurement (or useful upper limit) of one or more of the Ti, Cr, Co, Ni, Zn/Fe abundance ratios could be determined from detected absorption lines. For the remaining systems (without detections), we devised a new form of spectral stacking to estimate the typical Fe-peak element ratios of the DLA population in this metallicity regime. We compare these data to analogous measurements in metal-poor stars of the Galactic halo and to detailed calculations of explosive nucleosynthesis in metal-free stars. We conclude that most of the DLAs in our sample were enriched by stars that released an energy of ≲1.2 × 10^(51) erg when they exploded as core-collapse supernovae. Finally, we discuss the exciting prospect of measuring Fe-peak element ratios in DLAs with Fe/H < 1/1000 of solar when 30-m class telescopes become available. Only then will we be able to pin down the energy that was released by the supernovae of the first stars.
Additional Information
© 2013 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. Accepted 2013 February 12. Received 2013 February 12; in original form 2012 October 10. First published online: March 19, 2013. Based on observations collected at the European Organization for Astronomical Research in the Southern hemisphere, Chile [Proposals 67.A-0078(A), 69.A-0613(A), 083.A-0042(A) and 085.A-0109(A)], and at the W.M. Keck Observatory which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation. Keck telescope time was partially granted by NOAO, through the Telescope System Instrumentation Program (TSIP). TSIP is funded by NSF. We are grateful to the staff astronomers at the VLT and Keck Observatories for their assistance with the observations, and to the telescope time assignment committees for their support of the VMP DLA survey. We thank the referee, Paolo Molaro, for a prompt and helpful report that improved the paper, and Piercarlo Bonifacio for communicating his measurements of Cr/Fe in very metal poor stars. It is also a pleasure to acknowledge valuable discussions with Poul Nissen and Stan Woosley, regarding the stellar abundance measurements and nucleosynthesis calculations. We thank the Hawaiian people for the opportunity to observe from Mauna Kea; without their hospitality, this work would not have been possible. RC acknowledges the support of a Morrison Fellowship provided by the University of California, Santa Cruz. RAJ is supported by an NSF Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1102683. MTM thanks the Australian Research Council for a QEII Research Fellowship (DP0877998).Attached Files
Published - MNRAS-2013-Cooke-1625-37.pdf
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Additional details
- Eprint ID
- 38938
- Resolver ID
- CaltechAUTHORS:20130613-092507120
- University of California, Santa Cruz
- AST-1102683
- NSF Astronomy and Astrophysics Fellowship
- DP0877998
- Australian Research Council
- W. M. Keck Foundation
- Created
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2013-06-13Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field