Abstract
Interstellar gas is widely detected at intermediate velocities, both in H i emission at 21 cm and in optical and ultraviolet observations of trace elements seen in absorption toward distant stars. In the northern hemisphere, the distribution of intermediate-velocity clouds is dominated by several large complexes, and two weaker complexes have been identified recently in the southern hemisphere. Intermediate-velocity clouds are located in the lower Galactic Halo and most of them appear to be falling toward the galactic plane. They display a variety of physical conditions, but abundances consistently indicate grain disruption and a gas composition that is nearly solar. A range of models has been proposed to explain these basic characteristics but, at this time, no single scenario offers a compelling description of the intermediate-velocity cloud observations. Overall, evidence appears to be mounting in favor of identifying at least some of the intermediate-velocity clouds with the return flow of a Galactic Fountain. However, in individual cases, several different processes could also be at work and the relationship, if any, between high- and intermediate-velocity clouds is unclear. Intermediate-velocity clouds are a widespread phenomenon which may well play an important role in the dynamics and evolution of the gaseous component of our Galaxy.
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References
Adams, W.S. 1949, ApJ, 109, 354
Albert, C.E. 1983, ApJ, 272, 504
Albert, C.E., Blades, J.C., Morton, D.C., Lockman, F.J., Proulx, M., Ferrarese, L. 1993, ApJS, 88, 81
Anders, E., Grevesse, N. 1989, Geochim. Cosmochim. Acta, 53, 197
Arnal, E.M., Bajaja, E., Larrarte, J.J., Morras, R., Pöoppel, W.G.L. 2000, A&AS, 142, 35
Bajaja, E., Cappa de Nicolau, C.E., Cersosimo, J.C., Martin, M.C., Loiseau, N., Morras, R., Olano, C.A., Pöoppel, W.G.L. 1985, ApJS, 58, 143
Barnes, D.G., Staveley-Smith, L., de Blok, W.J.G., et 36 al. 2000, MNRAS, 322, 486
Bates, B., Brown-Kerr, W., Giaretta, D.L., Keenan, F.P. 1983, A&A, 122, 64
Bates, B., Catney, M.G., Keenan, F.P. 1990, MNRAS, 245, 238
Bates, B., Shaw, C.R., Kemp, S.N., Keenan, F.P., Davies, R.D. 1995, ApJ, 444, 672
Benjamin, R.A., Danly, L. 1997, ApJ, 481, 764
Benjamin, R.A., Venn, K.A., Hiltgen, D.D., Sneden, C. 1996, ApJ, 464, 836
Blaauw, A., Tolbert, C.R. 1966, BAN, 18, 405
Blom, J.J., Bloemen, H., Bykov, A.M., et 8 al. 1997, A&A, 321, 288
Bregman, J.N. 1980, ApJ, 236, 577
Brüns, C., Kerp, J., Staveley-Smith, L. 2000, in ASP Conf. Ser. 218, Mapping the Hidden Universe, eds. R.C. Kraan-Korteweg, P.A. Henning, H. Andernach (San Francisco: ASP), 349
Centurion, M., Vladilo, G., de Boer, K.S., Herbstmeier, U., Schwarz, U.J. 1994, A&A, 292, 261
Chu, Y.-H., Kennicutt, R.C. 1994, ApJ, 425, 720
Cohn, H., York, D.G. 1977, ApJ, 216, 408
Cowie, L.L., York, D.G. 1978, ApJ, 223, 876
Danly, L. 1987, Ph.D. thesis, University of Wisconsin-Madison
Danly, L. 1989, ApJ, 342, 785
Danly, L., Lockman, F.J., Meade, M.R., Savage, B.D. 1992, ApJS, 81, 125
Danly, L., Albert, C.E., Kuntz, K.D. 1993, ApJ, 416, L29
de Avillez, M.A. 1999, in ASP Conf. Ser. 166, Stromlo Workshop on High-Velocity Clouds, eds. B.K. Gibson, M.E. Putman (San Francisco: ASP), 103
de Boer, K.S., Savage, B.D. 1983, ApJ, 265, 210
de Boer, K.S., Rodriguez Pascual, P., Wamsteker, W., Sonneborn, G., Fransson, C., Bomans, D.J., Kirshner, R.P. 1993, A&A, 280, L15
de Heij, V. 1998, in The Physics and Chemistry of the Interstellar Medium, Abstract Book of the 3rd Cologne-Zermatt Symposium, ed. V. Ossenkopf (Aachen: Shaker-Verlag)
Fitzpatrick, E.L. 1996, ApJ, 473, L55
Fitzpatrick, E.L., Spitzer, L. 1997, ApJ, 475, 623
Frail, D.A., Weisberg, J.M., Cordes, J.M., Mathers, C. 1994, ApJ, 436, 144
Gladders, M.D., Clarke, T.E., Burns, C.R., et 9 al. 1998, ApJ, 507, L161
Gladders, M.D., Clarke, T.E., Burns, C.R., et 14 al. 1999, in ASP Conf. Ser. 166, Stromlo Workshop on High-Velocity Clouds, eds. B.K. Gibson, M.E. Putman (San Francisco: ASP), 45
Gringel, W., Barnstedt, J., de Boer, K.S., Grewing, M., Kappelmann, N., Richter, P. 2000, A&A, 358, L37
Habing, H.J. 1969, BAN, 20, 177
Hartmann, D. 2000, in ASP Conf. Ser. 217, Imaging at Radio through Submillimeter Wavelengths, eds. J.G. Mangum, S.J.E. Radford (San Francisco: ASP), 58
Hartmann, D., Burton, W.B. 1997, Atlas of Galactic Neutral Hydrogen (Cambridge: Cambridge University Press)
Heiles, C. 1984, ApJS, 55, 585
Heiles, C. 1997, ApJ, 481, 193
Howk, J.C., Savage, B.D. 1999, AJ, 117, 2077
Jaschek, C., Gomez, A.E. 1996, A&A, 330, 619
Keenan, F.P., Dufton, P.L., McKeith, C.D., Blades, J.C. 1983, MNRAS, 203, 963
Kennedy, D.C., Bates, B., Keenan, F.P., Kemp, S.N., Ryans, R.S.I., Davies, R.D., Sembach, K.R. 1998, MNRAS, 297, 849
Kerp, J., Mack, K.-H., Egger, R., Pietz, J., Zimmer, F., Mebold, U., Burton, W.B., Hartmann, D. 1996, A&A, 312, 67
Kerp, J., Burton, W.B., Egger, R., Freyberg, M.J., Hartmann, D., Kalberla, P.M.W., Mebold, U., Pietz, J. 1999, A&A, 342, 213
Knude, J., Hog, E. 1999, A&A, 341, 451
Kuntz, K.D., Danly, L. 1996, ApJ, 457, 703
Langer, G.E., Prosser, C.F., Sneden, C. 1990, AJ, 100, 216
Lauroesch J.T., Meyer, D.M., Blades, J.C. 2000, ApJ, 543, L43
Lehner, N., Rolleston, W.R.J., Ryans, R.S.I., Keenan, F.P., Bates, B., Pollacco, D.L., Sembach, K.R. 1999a, A&AS, 134, 257
Lehner, N., Sembach, K.R., Lambert, D.L., Ryans, R.S.I., Keenan, F.P. 1999b, A&A, 352, 257
Little, J.E., Dufton, P.L., Keenan, F.P., Conlon, E.S., Davies, R.D. 1994, ApJ, 427, 267
Lockman, F.J., Hobbs, L.M., Shull, J.M. 1986, ApJ, 301, 380
Mathewson, D.S., Cleary, M.N., Murray, J.D. 1974, ApJ, 190, 291
Meyer, D.M., Blades, J.C. 1996, ApJ, 464, L179
Meyer, D.M., Lauroesch, J.T. 1999, ApJ, 520, L103
Mirabel, I.F., Morras, R. 1990, ApJ, 356, 130
Morras, R. 1980, A&A, 92, 315
Morras, R., Bajaja, E., Arnal, E.M., Pöoppel, W.G.L. 2000, A&AS, 142, 25
Morton, D.C., Blades, J.C. 1986, MNRAS, 220, 927
Münch, G., Zirin, H. 1961, ApJ, 133, 11
Penprase, B.E., Blades, J.C. 1992, ApJ, 391, 276
Pietz, J., Kerp, J., Kalberla, P.M.W., Mebold, U., Burton, W.B., Hartmann, D. 1996, A&A, 308, L37
Pilachowski, C., Langer, E., Sneden, C., Kraft, R. 1998, BAAS, 30, 870
Rand, R.J., Stone, J.M. 1996, AJ, 111, 190
Richter, P., Savage, B.D., Wakker, B.P., Sembach, K.R., Kalberla, P.M.W. 2001a, ApJ, 549, 281
Richter, P., Sembach, K.R., Wakker, B.P., Savage, B.D., Tripp, T.M., Murphy, E.M., Kalberla, P.M.W., Jenkins, E.B. 2001b, ApJ, 559, 318
Richter, P., Wakker, B.P., Savage, B.D., Sembach, K.R. 2003, ApJ, 586, 230
Roberts, B.R. 1992, Investigation of a Possible Galactic Chimney, USNA Trident Scholar Report No. 196, U.S. Naval Academy, Annapolis, MD
Ryans, R.S.I., Hambly, N.C., Dufton, P.L., Keenan, F.P. 1996a, MNRAS, 278, 132
Ryans, R.S.I., Sembach, K.R., Keenan, F.P. 1996b, A&A, 314, 609
Ryans, R.S.I., Keenan, F.P., Sembach, K.R., Davies, R.D. 1997a, MNRAS, 289, 83
Ryans, R.S.I., Keenan, F.P., Sembach, K.R., Davies, R.D. 1997b, MNRAS, 289, 986
Ryans, R.S.I., Keenan, F.P., Rolleston, W.R.J., Sembach, K.R., Davies, R.D. 1999, MNRAS, 304, 947
Savage, B.D., Sembach, K.R. 1994, ApJ, 434, 145
Savage, B.D., Sembach, K.R. 1996a, ApJ, 470, 893
Savage, B.D., Sembach, K.R. 1996b, ARA&A, 34, 279
Savage, B.D., Sembach, K.R., Wakker, B.P., Richter, P., Meade, M., Jenkins, E.B., Shull, J.M., Moos, H.W., Sonneborn, G. 2003, ApJS, 146, 125
Schwarz, U.J., Wakker, B.P., van Woerden, H. 1995, A&A, 302, 364
Sembach, K.R. 1995, ApJ, 445, 314
Sembach, K.R., Savage, B.D. 1992, ApJS, 83, 147
Sembach, K.R., Savage, B.D., Tripp, T.M. 1997, ApJ, 480, 216
Sembach, K.R., Howk, J.C., Ryans, R.S.I., Keenan, F.P. 2000, ApJ, 528, 310
Shaw, C.R., Bates, B., Kemp, S.N., Keenan, F.P. 1996, ApJ, 473, 849
Shull, J.M., Beckwith, S. 1982, ARA&A, 20, 163
Slavin, J.D., McKee, C.F., Hollenbach, D.J. 2000, ApJ, 541, 218
Smoker, J.V., Lehner, N., Keenan, F.P., Totten, E.J., Murphy, E., Sembach, K.R., Davies, R.D., Bates, B. 2001, MNRAS, 322, 13
Smoker, J.V., Haffner, L.M., Keenan, F.P., Davies, R.D., Pollacco, D. 2002, MNRAS, 337, 385
Songaila, A., York, D.G. 1981, ApJ, 242, 976
Songaila, A., Cowie, L.L., Weaver, H.F. 1988, ApJ, 329, 580
Spitzer, L. 1978, Physical Processesin the Interstellar Medium (New York: Wiley-Interscience), 163
Spitzer, L., Fitzpatrick, E.L. 1992, ApJ, 391, L41
Spitzer, L., Fitzpatrick, E.L. 1993, ApJ, 409, 299
Spitzer, L., Fitzpatrick, E.L. 1995, ApJ, 445, 196
Spitzer, L., Fitzpatrick, E.L. 1997, ApJ, 475, 623
Stark, A.A., Gammie, C.F., Wilson, R.W., Bally, J., Linke, R.A., Heiles, C., Hurwitz, M. 1992, ApJS, 79, 77
Tolbert, C.R. 1971, A&AS, 3, 349
Wakker, B.P. 2001, ApJS, 136, 463
Wakker, B.P., Howk, J.C., Schwarz, U.J., van Woerden, H., Beers, T.C., Wilhelm, R., Kalberla, P.M.W., Danly, L. 1996, ApJ, 473, 834
Wakker, B.P., Kalberla, P.M.W., van Woerden, H., de Boer, K.S., Putman, M.E. 2001, ApJS, 136, 537
Watson, J.K., Meyer, D.M. 1996, ApJ, 473, L127
Welsh, B.Y., Craig, N., Roberts, B. 1996, A&A, 308, 428
Wesselius, P.R., Fejes, I. 1973, A&A, 24, 15
Wolfire, M.G., McKee, C.F., Hollenbach, D., Tielens, A.G.G.M. 1995, ApJ, 453, 673
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Elise Albert, C., Danly, L. (2004). Interemdiate-velocity Clouds. In: van Woerden, H., Wakker, B.P., Schwarz, U.J., de Boer, K.S. (eds) High-Velocity Clouds. Astrophysics and Space Science Library, vol 312. Springer, Dordrecht. https://doi.org/10.1007/1-4020-2579-3_4
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