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Star Formation on Galactic Scales: Empirical Laws

Published online by Cambridge University Press:  16 November 2011

B.G. Elmegreen*
Affiliation:
IBM T.J. Watson Research Center, 1101 Kitchawan Road, Yorktown Heights, New York 10598, USA
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Abstract

Empirical star formation laws from the last 20 years are reviewed with a comparison to simulations. The current form in main galaxy disks has a linear relationship between the star formation rate per unit area and the molecular cloud mass per unit area with a timescale for molecular gas conversion of about 2 Gyr. The local ratio of molecular mass to atomic mass scales nearly linearly with pressure, as determined from the weight of the gas layer in the galaxy. In the outer parts of galaxies and in dwarf irregular galaxies, the disk can be dominated by atomic hydrogen and the star formation rate per unit area becomes directly proportional to the total gas mass per unit area, with a consumption time of about 100 Gyr. The importance of a threshold for gravitational instabilities is not clear. Observations suggest such a threshold is not always important, while simulations generally show that it is. The threshold is difficult to evaluate because it is sensitive to magnetic and viscous forces, the presence of spiral waves and other local effects, and the equation of state.

Type
Research Article
Copyright
© EAS, EDP Sciences, 2011

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References

Bertin, G., & Amorisco, N.C., 2010, A & A, 512, 17CrossRef
Bigiel, F.,, Leroy, A., Walter, F., et al., 2008, AJ, 136, 2846CrossRef
Bigiel, F., Leroy, A., Seibert, M., et al., 2010a, ApJ, 720, 31CrossRef
Bigiel, F., Leroy, A., Walter, F., et al., 2010b [arXiv1007.3498]
Blitz, L., & Rosolowsky, E., 2006, ApJ, 650, 933CrossRef
Boissier, S., & Prantzos, N., 1999, MNRAS, 307, 857CrossRef
Boissier, S., Prantzos, N., Boselli, A., & Gavazzi, G., 2003, MNRAS, 346, 1215CrossRef
Boissier, S., Gil de Paz, A., Boselli, A., et al., 2008, ApJ, 681, 244CrossRef
Boselli, A., Lequeux, J., & Gavazzi, G., 2002, A & A, 384, 33CrossRef
Buat, V., Deharveng, J.M., & Donas, J., 1989, A & A, 223, 42
Burkert, A., Truran, J.W., & Hensler, G., 1992, ApJ, 391, 651CrossRef
Bush, S.J., Cox, T.J., Hayward, C.C., et al., 2010, ApJ, 713, 780CrossRef
Chandrasekhar, S., 1954, ApJ, 119, 7CrossRef
Chen, C.H.R., et al., 2010, ApJ, 721, 1206CrossRef
Dong, H., Calzetti, D., Regan, M., et al., 2008, AJ, 136, 479CrossRef
Dopita, M.A., & Ryder, S.D., 1994, ApJ, 430, 163CrossRef
Elmegreen, B.G., 1987, ApJ, 312, 626CrossRef
Elmegreen, B.G., 1989, ApJ, 338, 178CrossRef
Elmegreen, B.G., 1991, ApJ, 378, 139CrossRef
Elmegreen, B.G., 1994, ApJ, 433, 39CrossRef
Elmegreen, B.G., 2002, ApJ, 577, 206CrossRef
Elmegreen, B.G., & Parravano, A., 1994, ApJ, 435, L121CrossRef
Elmegreen, B.G., Palous, J., & Ehlerova, S., 2002, MNRAS, 334, 693CrossRef
Enoch, M.L., et al., 2006, ApJ, 638, 293CrossRef
Gammie, C.F., 1996, ApJ, 462, 725CrossRef
Gil de Paz, A., et al., 2005, ApJ, 627, L29CrossRef
Harfst, S., Theis, Ch., & Hensler, G., 2006, A & A, 449, 506CrossRef
Heyer, M.H., Corbelli, E., Schneider, S.E., & Young, J.S., 2004, ApJ, 602, 723CrossRef
Hunter, D.A., Elmegreen, B.G., Baker, A.L., 1998, ApJ, 493, 595CrossRef
Hunter, J.H. Jr., & Horak, T., 1983, ApJ, 265, 402CrossRef
Johnstone, D., Di Francesco, J., & Kirk, H., 2004, ApJ, 611, L45CrossRef
Jørgensen, J.K., Johnstone, D., Kirk, H., & Myers, P.C., 2007, ApJ, 656, 293CrossRef
Kennicutt, R.C. Jr., 1989, ApJ, 344, 685CrossRef
Kennicutt, R.C. Jr., 1998, ApJ, 498, 541CrossRef
Kennicutt, R.C. Jr., et al., 2007, ApJ, 671, 333CrossRef
Kim, W.-T., & Ostriker, E.C., 2001, ApJ, 559, 70CrossRef
Kim, W.-T., & Ostriker, E.C., 2002, ApJ, 570, 132CrossRef
Kim, W.-T., & Ostriker, E.C., 2007, ApJ, 660, 1232CrossRef
Kim, W.-T., Ostriker, E.C., & Stone, J.M., 2002, ApJ, 581, 1080CrossRef
Kirk, H., Johnstone, D., & Di Francesco, J., 2006, ApJ, 646, 1009CrossRef
Kravtsov, A.V., 2003, ApJ, 590, L1CrossRef
Krumholz, M.R., & McKee, C.F., 2005, ApJ, 630, 250CrossRef
Krumholz, M.R., & Tan, J.C., 2007, ApJ, 654, 304CrossRef
Krumholz, M.R., McKee, C.F., & Tumlinson, J., 2008, ApJ, 689, 865CrossRef
Krumholz, M.R., McKee, C.F., & Tumlinson, J., 2009a, ApJ, 693, 216CrossRef
Krumholz, M.R., McKee, C.F., & Tumlinson, J., 2009b, ApJ, 699, 850CrossRef
Larson, R.B., 1981, MNRAS, 194, 809CrossRef
Leroy, A., Bolatto, A.D., Simon, J.D., & Blitz, L., 2005, ApJ, 625, 763CrossRef
Leroy, A.K., Walter, F., Brinks, E., et al., 2008, AJ, 136, 2782CrossRef
Li, Y., Mac Low, M.-M., & Klessen, R.S., 2006, ApJ, 639, 879CrossRef
Luna, A., Bronfman, L., Carrasco, L., & May, J., 2006, ApJ, 641, 938CrossRef
Lynden-Bell, D., 1966, Observatory, 86, 57
Misiriotis, A., Xilouris, E.M., Papamastorakis, J., Boumis, P., & Goudis, C.D., 2006, A & A, 459, 113CrossRef
Murante, G., Monaco, P., Giovalli, M., Borgani, S., & Diaferio, A., 2010, MNRAS, 405, 1491
Myers, P.C., 1978, ApJ, 225, 380CrossRef
Robertson, B.E., & Kravtsov, A.V., 2008, ApJ, 680, 1083CrossRef
Rownd, B.K., & Young, J.S., 1999, AJ, 118, 670CrossRef
Scalo, J.M., 1986, Fund. Cos. Physics, 11, 1
Schmidt, M., 1959, ApJ, 129, 243CrossRef
Springel, V., & Hernquist, L., 2002, MNRAS, 333, 649CrossRef
Sternberg, A., McKee, C.F., & Wolfire, M.G., 2002, ApJS, 143, 419CrossRef
Stephenson, G., 1961, MNRAS, 122, 455CrossRef
Tasker, E.J., & Bryan, G.L., 2006, ApJ, 641, 878CrossRef
Thilker, D.A., et al., 2005, ApJ, 619, L79CrossRef
Toomre, A., 1964, ApJ, 139, 1217CrossRef
van Zee, L., Haynes, M.P., Salzer, J.J., & Broeils, A.H., 1996, AJ, 113, 1618CrossRef
Verley, S., Corbelli, E., Giovanardi, C., & Hunt, L.K., 2010, A & A, 510, 64CrossRef
Vorobyov, E.I., 2003, A & A, 407, 913CrossRef
Wada, K., & Norman, C.A., 2007, ApJ, 660, 276CrossRef
Wang, B., & Silk, J., 1994, ApJ, 427, 759CrossRef
Wong, T., & Blitz, L., 2002, ApJ, 569, 157CrossRef
Zasov, A.V., & Smirnova, A.A., 2005, Ast. L., 31, 160