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Title: The Origins of [C ii] Emission in Local Star-forming Galaxies

Abstract

The [C ii] 158 μ m 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{sup +} 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 μ m 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 μ m. 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 onmore » 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.« less

Authors:
 [1];  [2];  [3];  [4]; ;  [5];  [6];  [7];  [8];  [9];  [10];  [11];  [12];  [13];  [14];
  1. Department of Astronomy, The Ohio State University, 4051 McPherson Laboratory, 140 W. 18th Avenue, Columbus, OH, 43210 (United States)
  2. Max-Planck-Institut fur Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
  3. Department of Physics and Astronomy, University of Toledo, 2801 W. Bancroft Street, Toledo, OH 43606 (United States)
  4. Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611 (Australia)
  5. Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
  6. Max-Planck-Institut für extraterrestrische Physik, Giessen-bachstr., D-85748 Garching (Germany)
  7. Center for Astrophysics and Space Sciences, Department of Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093 (United States)
  8. Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)
  9. Spitzer Science Center, California Institute of Technology, MC 314-6, Pasadena, CA 91125 (United States)
  10. Unidad de Astronomía, Fac. Cs. Básicas, Universidad de Antofagasta, Avda. U. de Antofagasta 02800, Antofagasta (Chile)
  11. Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)
  12. Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States)
  13. Laboratoire AIM-Paris-Saclay, CEA/DSM/Irfu—CNRS—Université Paris Diderot, CEA-Saclay, 91191, Gif-sur-Yvette (France)
  14. INAF-Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, I-50125, Firenze (Italy)
Publication Date:
OSTI Identifier:
22663240
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 845; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; APPROXIMATIONS; BALANCES; CALIBRATION; CARBON IONS; COSMIC DUST; DENSITY; EMISSION; FAR ULTRAVIOLET RADIATION; FINE STRUCTURE; GALAXIES; HEAT EXCHANGERS; INFRARED SURVEYS; INTERSTELLAR SPACE; METALLICITY; METALS; PHOTOELECTRIC EFFECT; STAR EVOLUTION; STARS; SURFACES

Citation Formats

Croxall, K. V., Smith, J. D., Pellegrini, E., Groves, B., Bolatto, A., Wolfire, M. G., Herrera-Camus, R., Sandstrom, K. M., Draine, B., Armus, L., Boquien, M., Brandl, B., Dale, D., Galametz, M., Hunt, L., E-mail: jd.smith@utoledo.edu, and and others. The Origins of [C ii] Emission in Local Star-forming Galaxies. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA8035.
Croxall, K. V., Smith, J. D., Pellegrini, E., Groves, B., Bolatto, A., Wolfire, M. G., Herrera-Camus, R., Sandstrom, K. M., Draine, B., Armus, L., Boquien, M., Brandl, B., Dale, D., Galametz, M., Hunt, L., E-mail: jd.smith@utoledo.edu, & and others. The Origins of [C ii] Emission in Local Star-forming Galaxies. United States. doi:10.3847/1538-4357/AA8035.
Croxall, K. V., Smith, J. D., Pellegrini, E., Groves, B., Bolatto, A., Wolfire, M. G., Herrera-Camus, R., Sandstrom, K. M., Draine, B., Armus, L., Boquien, M., Brandl, B., Dale, D., Galametz, M., Hunt, L., E-mail: jd.smith@utoledo.edu, and and others. Sun . "The Origins of [C ii] Emission in Local Star-forming Galaxies". United States. doi:10.3847/1538-4357/AA8035.
@article{osti_22663240,
title = {The Origins of [C ii] Emission in Local Star-forming Galaxies},
author = {Croxall, K. V. and Smith, J. D. and Pellegrini, E. and Groves, B. and Bolatto, A. and Wolfire, M. G. and Herrera-Camus, R. and Sandstrom, K. M. and Draine, B. and Armus, L. and Boquien, M. and Brandl, B. and Dale, D. and Galametz, M. and Hunt, L., E-mail: jd.smith@utoledo.edu and and others},
abstractNote = {The [C ii] 158 μ m 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{sup +} 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 μ m 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 μ m. 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.},
doi = {10.3847/1538-4357/AA8035},
journal = {Astrophysical Journal},
number = 2,
volume = 845,
place = {United States},
year = {Sun Aug 20 00:00:00 EDT 2017},
month = {Sun Aug 20 00:00:00 EDT 2017}
}