Extremely metal-poor gas at a redshift of 7
In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar value. Lower abundances have been seen in selected stars in the Milky Way’s halo(1, 2, 3) and in two quasar absorption systems at redshift z = 3 (ref. 4). These are widely interpreted as rel...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | en_US |
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Nature Publishing Group
2013
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| Online Access: | http://hdl.handle.net/1721.1/79580 https://orcid.org/0000-0003-3769-9559 |
| _version_ | 1826195420550791168 |
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| author | Simcoe, Robert A. Sullivan, Peter W. Kao, Melodie M. Burgasser, Adam J. Cooksey, Kathy Matejek, Michael Scott |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Simcoe, Robert A. Sullivan, Peter W. Kao, Melodie M. Burgasser, Adam J. Cooksey, Kathy Matejek, Michael Scott |
| author_sort | Simcoe, Robert A. |
| collection | MIT |
| description | In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar value. Lower abundances have been seen in selected stars in the Milky Way’s halo(1, 2, 3) and in two quasar absorption systems at redshift z = 3 (ref. 4). These are widely interpreted as relics from the early Universe, when all gas possessed a primordial chemistry. Before now there have been no direct abundance measurements from the first billion years after the Big Bang, when the earliest stars began synthesizing elements. Here we report observations of hydrogen and heavy-element absorption in a spectrum of a quasar at z = 7.04, when the Universe was just 772 million years old (5.6 per cent of its present age). We detect a large column of neutral hydrogen but no corresponding metals (defined as elements heavier than helium), limiting the chemical abundance to less than 1/10,000 times the solar level if the gas is in a gravitationally bound proto-galaxy, or to less than 1/1,000 times the solar value if it is diffuse and unbound. If the absorption is truly intergalactic(5, 6), it would imply that the Universe was neither ionized by starlight nor chemically enriched in this neighbourhood at z ≈ 7. If it is gravitationally bound, the inferred abundance is too low to promote efficient cooling(7, 8), and the system would be a viable site to form the predicted but as yet unobserved massive population III stars. |
| first_indexed | 2024-09-23T10:12:23Z |
| format | Article |
| id | mit-1721.1/79580 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:12:23Z |
| publishDate | 2013 |
| publisher | Nature Publishing Group |
| record_format | dspace |
| spelling | mit-1721.1/795802022-09-30T19:36:07Z Extremely metal-poor gas at a redshift of 7 Simcoe, Robert A. Sullivan, Peter W. Kao, Melodie M. Burgasser, Adam J. Cooksey, Kathy Matejek, Michael Scott MIT Kavli Institute for Astrophysics and Space Research Simcoe, Robert A. Sullivan, Peter W. Cooksey, Kathy Kao, Melodie M. Matejek, Michael Scott In typical astrophysical environments, the abundance of heavy elements ranges from 0.001 to 2 times the solar value. Lower abundances have been seen in selected stars in the Milky Way’s halo(1, 2, 3) and in two quasar absorption systems at redshift z = 3 (ref. 4). These are widely interpreted as relics from the early Universe, when all gas possessed a primordial chemistry. Before now there have been no direct abundance measurements from the first billion years after the Big Bang, when the earliest stars began synthesizing elements. Here we report observations of hydrogen and heavy-element absorption in a spectrum of a quasar at z = 7.04, when the Universe was just 772 million years old (5.6 per cent of its present age). We detect a large column of neutral hydrogen but no corresponding metals (defined as elements heavier than helium), limiting the chemical abundance to less than 1/10,000 times the solar level if the gas is in a gravitationally bound proto-galaxy, or to less than 1/1,000 times the solar value if it is diffuse and unbound. If the absorption is truly intergalactic(5, 6), it would imply that the Universe was neither ionized by starlight nor chemically enriched in this neighbourhood at z ≈ 7. If it is gravitationally bound, the inferred abundance is too low to promote efficient cooling(7, 8), and the system would be a viable site to form the predicted but as yet unobserved massive population III stars. National Science Foundation (U.S.) (Award AST-0908920) National Science Foundation (U.S.) (Award AST-1109115) National Science Foundation (U.S.) (Postdoctoral Fellowship Program) 2013-07-11T14:52:15Z 2013-07-11T14:52:15Z 2012-12 2012-03 Article http://purl.org/eprint/type/JournalArticle 0028-0836 1476-4687 http://hdl.handle.net/1721.1/79580 Simcoe, Robert A., Peter W. Sullivan, Kathy L. Cooksey, Melodie M. Kao, Michael S. Matejek, and Adam J. Burgasser. Extremely Metal-poor Gas at a Redshift of 7. Nature 492, no. 7427 (December 5, 2012): 79-82. https://orcid.org/0000-0003-3769-9559 en_US http://dx.doi.org/10.1038/nature11612 Nature Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Nature Publishing Group arXiv |
| spellingShingle | Simcoe, Robert A. Sullivan, Peter W. Kao, Melodie M. Burgasser, Adam J. Cooksey, Kathy Matejek, Michael Scott Extremely metal-poor gas at a redshift of 7 |
| title | Extremely metal-poor gas at a redshift of 7 |
| title_full | Extremely metal-poor gas at a redshift of 7 |
| title_fullStr | Extremely metal-poor gas at a redshift of 7 |
| title_full_unstemmed | Extremely metal-poor gas at a redshift of 7 |
| title_short | Extremely metal-poor gas at a redshift of 7 |
| title_sort | extremely metal poor gas at a redshift of 7 |
| url | http://hdl.handle.net/1721.1/79580 https://orcid.org/0000-0003-3769-9559 |
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