The origins of [C ii] emission in local star-forming galaxies
The [C II] 158 μm fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [C II] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However,...
| Main Authors: | , , , , , , , , , , , , , , , , , , , |
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| Format: | Journal article |
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Institute of Physics
2017
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| _version_ | 1797060684908855296 |
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| author | Croxall, KV Smith, JD Pellegrini, E Groves, B Bolatto, A Herrera-Camus, R Sandstrom, KM Draine, B Wolfire, MG Armus, L Boquien, M Brandl, B Dale, D Galametz, M Hunt, L Kennicutt, R Kreckel, K Rigopoulou, D Werf, PVD Wilson, C |
| author_facet | Croxall, KV Smith, JD Pellegrini, E Groves, B Bolatto, A Herrera-Camus, R Sandstrom, KM Draine, B Wolfire, MG Armus, L Boquien, M Brandl, B Dale, D Galametz, M Hunt, L Kennicutt, R Kreckel, K Rigopoulou, D Werf, PVD Wilson, C |
| author_sort | Croxall, KV |
| collection | OXFORD |
| description | The [C II] 158 μm fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [C II] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However, the origin of [C II] emission remains unclear because C+ can be found in multiple phases of the interstellar medium. Here we measure the fractions of [C II] emission originating in the ionized and neutral gas phases of a sample of nearby galaxies. We use the [N II] 205 μm fine-structure line to trace the ionized medium, thereby eliminating the strong density dependence that exists in the ratio of [C II]/[N II] 122 μm. Using the FIR [C II] and [N II] emission detected by the KINGFISH (Key Insights on Nearby Galaxies: a Far- Infrared Survey with Herschel) and Beyond the Peak Herschel programs, we show that 60%–80% of [C II] emission originates from neutral gas. We find that the fraction of [C II] originating in the neutral medium has a weak dependence on dust temperature and the surface density of star formation, and has a stronger dependence on the gas-phase metallicity. In metal-rich environments, the relatively cooler ionized gas makes substantially larger contributions to total [C II] emission than at low abundance, contrary to prior expectations. Approximate calibrations of this metallicity trend are provided. |
| first_indexed | 2024-03-06T20:20:36Z |
| format | Journal article |
| id | oxford-uuid:2da8286c-8a04-45f5-b300-d2dd0b650247 |
| institution | University of Oxford |
| last_indexed | 2024-03-06T20:20:36Z |
| publishDate | 2017 |
| publisher | Institute of Physics |
| record_format | dspace |
| spelling | oxford-uuid:2da8286c-8a04-45f5-b300-d2dd0b6502472022-03-26T12:44:22ZThe origins of [C ii] emission in local star-forming galaxiesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:2da8286c-8a04-45f5-b300-d2dd0b650247Symplectic Elements at OxfordInstitute of Physics2017Croxall, KVSmith, JDPellegrini, EGroves, BBolatto, AHerrera-Camus, RSandstrom, KMDraine, BWolfire, MGArmus, LBoquien, MBrandl, BDale, DGalametz, MHunt, LKennicutt, RKreckel, KRigopoulou, DWerf, PVDWilson, CThe [C II] 158 μm fine-structure line is the brightest emission line observed in local star-forming galaxies. As a major coolant of the gas-phase interstellar medium, [C II] balances the heating, including that due to far-ultraviolet photons, which heat the gas via the photoelectric effect. However, the origin of [C II] emission remains unclear because C+ can be found in multiple phases of the interstellar medium. Here we measure the fractions of [C II] emission originating in the ionized and neutral gas phases of a sample of nearby galaxies. We use the [N II] 205 μm fine-structure line to trace the ionized medium, thereby eliminating the strong density dependence that exists in the ratio of [C II]/[N II] 122 μm. Using the FIR [C II] and [N II] emission detected by the KINGFISH (Key Insights on Nearby Galaxies: a Far- Infrared Survey with Herschel) and Beyond the Peak Herschel programs, we show that 60%–80% of [C II] emission originates from neutral gas. We find that the fraction of [C II] originating in the neutral medium has a weak dependence on dust temperature and the surface density of star formation, and has a stronger dependence on the gas-phase metallicity. In metal-rich environments, the relatively cooler ionized gas makes substantially larger contributions to total [C II] emission than at low abundance, contrary to prior expectations. Approximate calibrations of this metallicity trend are provided. |
| spellingShingle | Croxall, KV Smith, JD Pellegrini, E Groves, B Bolatto, A Herrera-Camus, R Sandstrom, KM Draine, B Wolfire, MG Armus, L Boquien, M Brandl, B Dale, D Galametz, M Hunt, L Kennicutt, R Kreckel, K Rigopoulou, D Werf, PVD Wilson, C The origins of [C ii] emission in local star-forming galaxies |
| title | The origins of [C ii] emission in local star-forming galaxies |
| title_full | The origins of [C ii] emission in local star-forming galaxies |
| title_fullStr | The origins of [C ii] emission in local star-forming galaxies |
| title_full_unstemmed | The origins of [C ii] emission in local star-forming galaxies |
| title_short | The origins of [C ii] emission in local star-forming galaxies |
| title_sort | origins of c ii emission in local star forming galaxies |
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