Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests
The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter γ. We describe a new method to measure γ using the ratio of flux curvature in the Lyman α and β forests. At a given r...
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| Format: | Article |
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Oxford University Press
2016
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| Online Access: | https://eprints.nottingham.ac.uk/42516/ |
| _version_ | 1848796504709398528 |
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| author | Boera, Elisa Murphy, Michael T. Becker, George D. Bolton, James S. |
| author_facet | Boera, Elisa Murphy, Michael T. Becker, George D. Bolton, James S. |
| author_sort | Boera, Elisa |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter γ. We describe a new method to measure γ using the ratio of flux curvature in the Lyman α and β forests. At a given redshift, this curvature ratio incorporates information from the different gas densities traced by Lyman α and β absorption. It is relatively simple and fast to compute and appears robust against several observational uncertainties. We apply this technique to a sample of 27 high-resolution quasar spectra from the Very Large Telescope. While promising statistical errors on γ appear to be achievable with these spectra, to reach its full potential, the dependence of the curvature ratio on the thermal state of the gas in the foreground Lyman α forest will require further, detailed forward modelling. |
| first_indexed | 2025-11-14T19:49:02Z |
| format | Article |
| id | nottingham-42516 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| last_indexed | 2025-11-14T19:49:02Z |
| publishDate | 2016 |
| publisher | Oxford University Press |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-425162020-05-04T17:37:19Z https://eprints.nottingham.ac.uk/42516/ Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests Boera, Elisa Murphy, Michael T. Becker, George D. Bolton, James S. The post-reionization thermal state of the intergalactic medium is characterized by a power-law relationship between temperature and density, with a slope determined by the parameter γ. We describe a new method to measure γ using the ratio of flux curvature in the Lyman α and β forests. At a given redshift, this curvature ratio incorporates information from the different gas densities traced by Lyman α and β absorption. It is relatively simple and fast to compute and appears robust against several observational uncertainties. We apply this technique to a sample of 27 high-resolution quasar spectra from the Very Large Telescope. While promising statistical errors on γ appear to be achievable with these spectra, to reach its full potential, the dependence of the curvature ratio on the thermal state of the gas in the foreground Lyman α forest will require further, detailed forward modelling. Oxford University Press 2016-02-11 Article PeerReviewed Boera, Elisa, Murphy, Michael T., Becker, George D. and Bolton, James S. (2016) Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests. Monthly Notices of the Royal Astronomical Society, 456 (1). L79-L83. ISSN 1365-2966 intergalactic medium quasar: absorption lines cosmology: observations https://academic.oup.com/mnrasl/article-lookup/doi/10.1093/mnrasl/slv172 doi:10.1093/mnrasl/slv172 doi:10.1093/mnrasl/slv172 |
| spellingShingle | intergalactic medium quasar: absorption lines cosmology: observations Boera, Elisa Murphy, Michael T. Becker, George D. Bolton, James S. Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title | Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title_full | Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title_fullStr | Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title_full_unstemmed | Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title_short | Constraining the temperature–density relation of the intergalactic medium with the Lyman-alpha and beta forests |
| title_sort | constraining the temperature–density relation of the intergalactic medium with the lyman-alpha and beta forests |
| topic | intergalactic medium quasar: absorption lines cosmology: observations |
| url | https://eprints.nottingham.ac.uk/42516/ https://eprints.nottingham.ac.uk/42516/ https://eprints.nottingham.ac.uk/42516/ |