Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
권호 표지
DOI QR코드

DOI QR Code

FAR-INFRARED [C II] EMISSION FROM THE CENTRAL REGIONS OF SPIRAL GALAXIES

  • Published : 2004.12.01
Download PDF
⟨ Previous Next ⟩

Abstract

Anomalies in the far-infrared [C II] 158 ${\mu}m$ line emission observed in the central one-kiloparsec regions of spiral galaxies are reviewed. Low far-infrared intensity ratios of the [C II] line to the continuum were observed in the center of the Milky Way, because the heating ratio of the gas to the dust is reduced by the soft interstellar radiation field due to late-type stars in the Galactic bulge. In contrast, such low line-to-continuum ratios were not obtained in the center of the nearby spiral M31, in spite of its bright bulge. A comparison with numerical simulations showed that a typical column density of the neutral interstellar medium between illuminating sources at $hv {\~} 1 eV $ is $N_H {\le}10^{21}\;cm^{-2}$ in the region; the medium is translucent for photons sufficiently energetic to heat the grains but not sufficiently energetic to heat the gas. This interpretation is consistent with the combination of the extremely high [C Il]/CO J = 1-0 line intensity ratios and the low recent star-forming activity in the region; the neutral interstellar medium is not sufficiently opaque to protect the species even against the moderately intense incident UV radiation. The above results were unexpected from classical views of the [C II] emission, which was generally considered to trace intense interstellar UV radiation enhanced by active star formation.

Keywords

References

  1. Blair, W. R, Kirshner, R. R, & Chevalier, R. A. 1982, ApJ, 254, 50 https://doi.org/10.1086/159703
  2. Brown, T. M., Ferguson, H. C., Stanford, S. A., & Deharveng, J.-M. 1998, ApJ, 504, 113 https://doi.org/10.1086/306079
  3. Clegg, P. E., et al. 1996, A&A, 315, L38
  4. Cohen, R. S., Dame, T. M., Garay, G., Montani, J., Rubio, M., & Thaddeus, P. 1988, ApJ, 331, L95 https://doi.org/10.1086/185243
  5. Cram, T. R., Roberts, M. S., & Whitehurst, R. N. 1980 A&AS, 40, 215
  6. de Jong, T. 1977, A&A, 55, 137
  7. Haas, M., Lemke, D., Stickel, M., Hippelein, H., Kunkel, M., Herbstmeier, U., & Mattila, K. 1998, A&A, 338, L33
  8. Hollenbach, D. J., Takahashi, T., & Tielens, A. G. G. M., 1991, ApJ, 377, 192 https://doi.org/10.1086/170347
  9. Hunter, D. A., et al. 2001, ApJ, 553, 121 https://doi.org/10.1086/320654
  10. Israel, F. P., Maloney, P. R., Geis, N., Herrmann, F., Madden, S. C., Poglisch, A., & Stacey, G. J. 1996, ApJ, 465, 738 https://doi.org/10.1086/177458
  11. Israel, F. P., Baas, F., Rudy, R. J., Skillman, E. D., & Woodward, C. E. 2003, A&A, 397, 87 https://doi.org/10.1051/0004-6361:20021464
  12. Kessler, M. F., et al. 1996, A&A, 315, L27
  13. Loinard, L., Dame, T. M., Heyer, M. H., Lequeux, J., & Thaddeus, P. 1999, A&A, 351, 1087
  14. Lord, S. D., et al. 1995, in ASP Conf. Ser. 73, Airborne Astronomy Symposium on the Galactic Ecosystem: From Gas to Stars to Dust, ed. M. R. Haas, et al (San Francisco: ASP), 151
  15. Luhman, M. L., et al. 1998, ApJ, 504, Ll https://doi.org/10.1086/306088
  16. Madden, S. C., Poglisch, A., Geis, N., Stacey, G. J., & Townes, C. H. 1997, ApJ, 483, 200 https://doi.org/10.1086/304247
  17. Malhotra, S., et al. 1997, ApJ, 491, L27 https://doi.org/10.1086/311044
  18. Malhotra, S., et al. 2000, ApJ, 543, 634 https://doi.org/10.1086/317119
  19. Malhotra, S., et al. 2001, ApJ, 561, 766 https://doi.org/10.1086/323046
  20. Maloney, P., & Black, J. H. 1988, ApJ, 325, 389 https://doi.org/10.1086/166011
  21. Martinez Roger, C., Phillips, J. P., Sanchez Magro, C. 1986, A&A, 161, 237
  22. Mochizuki, K. 2000, A&A, 363, 1123
  23. Mochizuki, K. 2004, ApJ, submitted
  24. Mochizuki, K., & Nakagawa, T. 2000, ApJ, 535, 118 https://doi.org/10.1086/308839
  25. Mochizuki, K., & Onaka, T. 2001, A&A, 370, 868 https://doi.org/10.1051/0004-6361:20010281
  26. Mochizuki, K., et al. 1994, ApJ, 430, L37 https://doi.org/10.1086/187432
  27. Nakagawa, T., Doi, Y., Yui, Y. Y., Okuda, H., Mochizuki, K., Shibai, H., Nishimura, T., & Low, F. J. 1995, ApJ, 455, L35
  28. Nakagawa, T., Yui, Y. Y., Doi, Y., Okuda, H., Shibai, H., Mochizuki, K., Nishimura, T., & Low, F. J. 1998, ApJS,115, 259 https://doi.org/10.1086/313082
  29. Pierini, D., Leech, K. J., Tuffs, R. J., & V$\ddot{o}$lk, H. J 1999, MNRAS, 303, L29 https://doi.org/10.1046/j.1365-8711.1999.02401.x
  30. Pierini, D., Leech, K. J., & V$\ddot{o}$lk, H. J. 2003, A&A, 397, 871 https://doi.org/10.1051/0004-6361:20021572
  31. Poglitsch, A., Krabbe, A., Madden, S. C., Nikola, T., Geis, N., Johansson, L. E. B., Stacey, G. J., & Sternberg, A. 1995, ApJ, 454, 293 https://doi.org/10.1086/176482
  32. Stacey, G. J., Geis, N., Genzel, R., Lugten, J. B., Poglitsch, A., Sternberg, A., & Townes, C. H. 1991, ApJ,373, 423 https://doi.org/10.1086/170062
  33. van Dishoeck, E. F., & Black, J. H. 1988, ApJ, 334, 771 https://doi.org/10.1086/166877

Cited by

  1. RESOLVING THE FAR-IR LINE DEFICIT: PHOTOELECTRIC HEATING AND FAR-IR LINE COOLING IN NGC 1097 AND NGC 4559 vol.747, pp.1, 2012, https://doi.org/10.1088/0004-637X/747/1/81
  2. Insights into gas heating and cooling in the disc of NGC 891 fromHerschelfar-infrared spectroscopy vol.575, 2015, https://doi.org/10.1051/0004-6361/201424732
  3. The Survey of Lines in M31 (SLIM): The Drivers of the [C ii]/TIR Variation vol.842, pp.2, 2017, https://doi.org/10.3847/1538-4357/aa7265