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Diffuse Ionized Gas in Halos of Spiral Galaxies

Published online by Cambridge University Press:  12 April 2016

Ralf-Jürgen Dettmar*
Affiliation:
Astronomisches Institut, Ruhr-Universitat Bochum, D-44780 Bochum, Germany

Abstract

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Over the last couple of years Diffuse Ionized Gas (DIG) has been identified as an important constituent of the interstellar medium (ISM) in the halos of spiral galaxies. Imaging in and spectroscopy of optical emission lines allow us to study the distribution and excitation of this gas with a spatial resolution not achievable for other phases of the ISM in external galaxies. Its origin and ionization is under debate and give important constraints for models of the ISM in general and on the large scale exchange of matter between disk and halo in particular. This review summarizes more recent observational results and compares them with model predictions. The data available now demonstrate that the presence of DIG in the disk-halo interface of spiral galaxies is related to star formation processes in the underlying disk. While photoionization by OB stars in the disk seems a viable source for the power required to ionize the DIG, additional processes are needed to explain some of the spectral features. The observed correlation with properties of the non-thermal radio continuum indicate that magnetic fields and cosmic rays could play a role for the physics of this medium.

Type
Part IX External Galaxies
Copyright
Copyright © Springer-Verlag 1998

References

Beck, R. (1997) in The Physics of Galactic Halos, eds.: Lesch, H., Dettmar, R.-J., Mebold, U. Schlickeiser, R., Akademie Verlag, p. 135 Google Scholar
Beuermann, K., Kanbach, G., Berkhuijsen, E.M. (1985): A&A 153, 17 Google Scholar
Birk, G.T., Lesch, H. (1997): these proceedingsGoogle Scholar
Bregman, J.N. (1980): ApJ 236, 577 CrossRefGoogle Scholar
Breitschwerdt, D. (1997): in The Physics of Galactic Halos, eds.: Lesch, H., Dettmar, R.-J., Mebold, U., Schlickeiser, R., Akademie Verlag, p.237 Google Scholar
Bregman, J.N., Pildis, R.A. (1994): ApJ 420, 570 CrossRefGoogle Scholar
Carilli, C.L., Holdaway, M.A., Ho, P.T.P., de Pree, C.G. (1992): ApJ 399, L59 CrossRefGoogle Scholar
Cox, P., Mezger, P.G. (1989): A&AR1, 49 Google Scholar
Dahlem, M. (1997): PASP, in press (ESA preprint)Google Scholar
Dahlem, M., Dettmar, R.-J., Hummel, E. (1994): A&A 290, 284 Google Scholar
Dahlem, M., Petr, M.G., Lehnert, M.D., Heekman, T.M., Ehle, M. (1997): A&A 320, 731 Google Scholar
Dettmar, R.-J. (1990): A&A 232, L15 Google Scholar
Dettmar, R.-J. (1992): Fund. Cosmic Phys. 15, 148 Google Scholar
Dettmar, R.-J. (1995): in The Physics of the Interstellar Medium and Intergalactic Medium, eds. Ferrara, A., McKee, C.F., Heiles, C., Р. Shapiro, R., ASP conf. Ser. Vol. 80, p. 398 Google Scholar
Dettmar, R.-J., Schulz, H. (1992): A&A 254, L25 Google Scholar
Domgörgen, H., Dettmar, R.-J. (1997): A&A 322, 391 Google Scholar
Domgörgen, H., Mathis, J.S. (1994): ApJ 428, 647 CrossRefGoogle Scholar
Donahue, M., Aldering, G., Stocke, J.T. (1995): ApJ 450, L45 CrossRefGoogle Scholar
Dove, J.B., Shull, J.M. (1994): ApJ 430, 222 CrossRefGoogle Scholar
Dumke, M., Krause, M., Wielebinski, R., Klein, U. (1995): A&A 302, 691 Google Scholar
Duric, N., Seaquist, E.R., Crane, P.C., Bignell, R.C., Davies, L.E. (1983): ApJ 273, L11 CrossRefGoogle Scholar
English, J., Irwin, J.A. (1997): AJ 113, 2006 CrossRefGoogle Scholar
Ferguson, A.M.N., Wyse, R.F.G., Gallagher, J.S., Hunter, D.A. (1996a): AJ 111, 2265 CrossRefGoogle Scholar
Ferguson, A.M.N., Wyse, R.F.G., Gallagher, J.S. (1996b): AJ 112, 256 CrossRefGoogle Scholar
Ferrara, A. (1997): in The Physics of Galactic Halos, eds.: Lesch, H. R.-J., Dettmar U.Mebold, R.Schlickeiser, , Akademie Verlag, p. 189 Google Scholar
Ferrara, A., Dettmar, R.-J. (1994): ApJ 427, 155 CrossRefGoogle Scholar
Ferrara, A., Bianchi, S., Dettmar, R.-J., Giovanardi, C (1996): ApJ 467, L69 CrossRefGoogle Scholar
Freyberg, M. (1997): these proceedingsGoogle Scholar
Fullmer, L., Lonsdale, C. (1989): Cataloged Galaxies and Quasars observed in the IRAS Survey, JPLGoogle Scholar
Golia, G., Dettmar, R.-J., Domgörgen, H. (1996): A&A 313, 439 Google Scholar
Habe, A., Ikeuchi, S. (1980): Prog. Theor. Phys., 64, 1995 CrossRefGoogle Scholar
Handa, T., Sofue, Y., Ikeuchi, S., Kawabe, R., Ishizuki, S. (1992): PASJ 44, L227 Google Scholar
Heiles, C, Koo, B.-C., Levenson, N.A., Reach, W.T. (1996): ApJ 462, 326 CrossRefGoogle Scholar
Hoopes, C.G., Walterbos, R.A.M., Greenawalt, B.E. (1996): AJ 112, 1429 CrossRefGoogle Scholar
Hummel, E., Dettmar, R.-J. (1990): A&A 236, 33 Google Scholar
Hummel, E., Beck, R., Dettmar, R.-J. (1991a): A&AS 87, 309 Google Scholar
Hummel, E., Beck, R., Dahlem, M. (1991b): A&A 248, 23 Google Scholar
Ikeuchi, S. (1997): these proceedingsGoogle Scholar
Kahn, F.D. (1997): these proceedingsGoogle Scholar
Keppel, J.W., Dettmar, R.-J., Gallagher, J.S., Roberts, M. (1990): ApJ 374, 507 CrossRefGoogle Scholar
Kulkarni, S.R., Heiles, C. (1988): in Galactic and Extragalactic Radioastronomy, 2nd edition, eds. Verschuur, G.L., Kellermann, K.I., Springer, p. 95 CrossRefGoogle Scholar
Lehnert, M.D., Heekman, T.M. (1994): ApJ 426, L27 CrossRefGoogle Scholar
Mac Low, M.-M., McCray, R., Norman, M.L. (1989): ApJ 337, 141 CrossRefGoogle Scholar
Mac Low, M.-M., Ferrara, A. (1997): these proceedingsGoogle Scholar
Mathis, J.S. (1986): ApJ 301, 423 CrossRefGoogle Scholar
Miller, W.W., Cox, D.P. (1993): ApJ 417, 579 CrossRefGoogle Scholar
Minter, A.H., Baiser, D.S. (1997): ApJ 484, L133 CrossRefGoogle Scholar
Norman, C.A., Ikeuchi, S. (1989): ApJ 345, 372 CrossRefGoogle Scholar
Pietsch, W. (1994): in Panchromatic Views of Galaxies, eds.: Hensler, , Theis, , Gallagher, , p. 134 Google Scholar
Pildis, R.A., Bregman, J.N., Schombert, J.M. (1994a): ApJ 423, 190 CrossRefGoogle Scholar
Pildis, R.A., Bregman, J.N., Schombert, J.M. (1994b): ApJ 427, 160 CrossRefGoogle Scholar
Rand, R.J. (1995): in Gas Disks in Galaxies ed. van der Hulst, J.M., Kluwer, in press (Univ. of Maryland preprint)Google Scholar
Rand, R.J. (1996): ApJ 462 712 CrossRefGoogle Scholar
Rand, R.J. (1997): ApJ 474, 129 CrossRefGoogle Scholar
Rand, R.J., Kulkarni, S.R., Hester, J.J. (1990): ApJ 352, L1 (Err. 362, L35)CrossRefGoogle Scholar
Rand, R.J., Kulkarni, S.R., Hester, J.J. (1992): ApJ 396, 97 CrossRefGoogle Scholar
Raymond, J.C. (1992): ApJ 384, 502 CrossRefGoogle Scholar
Reynolds, R.J. (1990): in IAU Symp. l44 The interstellar disk-halo connection in galaxies ed. Bloemen, H., Kluwer, p.Google Scholar
Reynolds, R.J. (1997): in The Physics of Galactic Halos, eds. Lesch, H., Dettmar, R.-J., Mebold, U., Schlickeiser, R., Akademie Verlag Berlin 1997, p. 57 Google Scholar
Reynolds, R.J., Cox, D.P. (1992): ApJ 400, L33 CrossRefGoogle Scholar
Reynolds, R.J., Tufte, S.L. (1995): ApJ 439, L17 CrossRefGoogle Scholar
Rice, W., Lonsdale, C.J., Soifer, B.T. et al. (1988): ApJS 68, 91 CrossRefGoogle Scholar
Schlickeiser, R., Werner, W., Wielebinski, R. (1984): A&A 140, 277 Google Scholar
Sciama, D.W., Salucci, P. (1991): MNRAS 247, 506 Google Scholar
Shapiro, P.R., Benjamin, R.A. (1993): in Starforming Galaxies and their Interstellar Medium eds. Franco, J.J. and Ferrini, F., Cambridge, p. 273 Google Scholar
Shapiro, P.R., Field, G.B. (1976): ApJ 205, 762 CrossRefGoogle Scholar
Slavin, J.D., Shull, J.M., Begelman, M.C.: (1993): ApJ 407, 83 CrossRefGoogle Scholar
Sofue, Y., Wakamatsu, K.-I., Malin, D.F. (1994): AJ 108, 2102 CrossRefGoogle Scholar
Sukumar, S., Alien, R.J. (1991): ApJ 382, 100 CrossRefGoogle Scholar
Swaters, R.A., Sancisi, R., van der Hulst, J.M. (1996): in IAU Symp. 171 New Light on Galaxy Evolution eds. Bender, R. and Davies, R.L., Kluwer, p. 450 CrossRefGoogle Scholar
Thronson, H.A., Telesco, C.M. (1986): ApJ 311, 98 CrossRefGoogle Scholar
Tully, R.B. (1988): Nearby Galaxies Catalog, Cambridge Google Scholar
Veilleux, S., Cecil, G., Bland-Hawthorn, J. (1995): ApJ 445, 112 CrossRefGoogle Scholar
Vogler, A., Pietsch, W., Kahabka, P. (1996): A&A 305, 74 Google Scholar
Walterbos, R.A.M. (1991): in IAU Symp. 144 The interstellar disk-halo connection in galaxies ed. Bloemen, H., Kluwer, p. 223 CrossRefGoogle Scholar
Wang, D., Walterbos, R., Steakley, M., Norman, C.N., Braun, R. (1995): ApJ 439, 176 CrossRefGoogle Scholar