Toward a Removal of Temperature Dependencies from Abundance Determinations: NGC 628
| Autor: | Kevin V. Croxall, Eva Schinnerer, K. Kreckel, Robert C. Kennicutt, Fabian Walter, D. Calzetti, L. Armus, B. D. Johnson, Bernhard R. Brandl, Brent Groves, Maud Galametz, P. Beirao, Jd Smith, Karin Sandstrom, Daniel A. Dale, Jin Koda, L. K. Hunt, Eric W. Pellegrini, J. L. Hinz |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Physics
010308 nuclear & particles physics Doubly ionized oxygen Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Plasma Astrophysics 01 natural sciences Galaxy Interstellar medium 13. Climate action Space and Planetary Science Abundance (ecology) 0103 physical sciences Astrophysics::Solar and Stellar Astrophysics Electron temperature Emission spectrum 010303 astronomy & astrophysics Astrophysics::Galaxy Astrophysics Line (formation) |
| Zdroj: | The Astrophysical Journal The Astrophysical Journal, 777, 96 |
| ISSN: | 0004-637X |
| DOI: | 10.1088/0004-637X/777/2/96 |
| Popis: | The metal content of a galaxy, a key property for distinguishing between viable galaxy evolutionary scenarios, strongly influences many of the physical processes in the interstellar medium. An absolute and robust determination of extragalactic metallicities is essential in constraining models of chemical enrichment and chemical evolution. Current gas-phase abundance determinations, however, from optical fine-structure lines are uncertain to 0.8 dex as conversion of these optical line fluxes to abundances is strongly dependent on the electron temperature of the ionized gas. In contrast, the far-infrared (far-IR) emission lines can be used to derive an O$^{++}$ abundance that is relatively insensitive to temperature, while the ratio of the optical to far-IR lines provides a consistent temperature to be used in the derivation of an O$^{+}$ abundance. We present observations of the [O III] 88 {$μ$}m fine-structure line in NGC 628 that were obtained as part of the Key Insights on Nearby Galaxies: a Far Infared Survey with Herschel program. These data are combined with optical integrated field unit data to derive oxygen abundances for seven H II regions. We find the abundance of these regions to all lie between the high and low values of strong-line calibrations and to be in agreement with estimates that assume temperature fluctuations are present in the H II regions. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. |
| Databáze: | OpenAIRE |
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