Abstract
Near infrared images from the COBE satellite presented the first clear evidence that our Milky Way galaxy contains a boxy shaped bulge. Recent years have witnessed a gradual paradigm shift in the formation and evolution of the Galactic bulge. Bulges were commonly believed to form in the dynamical violence of galaxy mergers. However, it has become increasingly clear that the main body of the Milky Way bulge is not a classical bulge made by previous major mergers, instead it appears to be a bar seen somewhat end-on. The Milky Way bar can form naturally from a precursor disc and thicken vertically by the internal firehose/buckling instability, giving rise to the boxy appearance. This picture is supported by many lines of evidence, including the asymmetric parallelogram shape, the strong cylindrical rotation (i.e., nearly constant rotation regardless of the height above the disc plane), the existence of an intriguing X-shaped structure in the bulge, and perhaps the metallicity gradients. We review the major theoretical models and techniques to understand the Milky Way bulge. Despite the progresses in recent theoretical attempts, a complete bulge formation model that explains the full kinematics and metallicity distribution is still not fully understood. Upcoming large surveys are expected to shed new light on the formation history of the Galactic bulge.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsNotes
- 1.
It is puzzling why no galaxy has been caught in the process of violent buckling as shown in Fig. 10.2. The saturation timescale of the buckling instability is very rapid (about a few hundred Myr), but it is not short enough to miss out the violent buckling phase if one can observe thousands of edge-on barred galaxies. Perhaps this implies that the buckling instability must have happened in the very early assembly stage of disc galaxies, which is much harder to observe.
References
Alves-Brito A., Meléndez J., Asplund M., Ramírez I., Yong D., 2010, A&A, 513, A35
Athanassoula E., 2005, MNRAS, 358, 1477
Baba J., Saitoh T. R., Wada K., 2010, PASJ, 62, 1413
Babusiaux C. et al., 2010, A&A, 519, A77
Bekki K., Tsujimoto T., 2011, MNRAS, 416, L60
Benjamin R. A. et al., 2005, ApJ, 630, L149
Bensby T. et al., 2011, A&A, 533, A134
Bensby T. et al., 2012, in Astronomical Society of the Pacific Conference Series, Vol. 458, Galactic Archaeology: Near-Field Cosmology and the Formation of the Milky Way, Aoki W., Ishigaki M., Suda T., Tsujimoto T., Arimoto N., eds., p. 203
Binney J., 1978, MNRAS, 183, 501
Binney J., Gerhard O. E., Stark A. A., Bally J., Uchida K. I., 1991, MNRAS, 252, 210
Bissantz N., Debattista V. P., Gerhard O., 2004, ApJ, 601, L155
Bissantz N., Englmaier P., Gerhard O., 2003, MNRAS, 340, 949
Bissantz N., Gerhard O., 2002, MNRAS, 330, 591
Blitz L., Spergel D. N., 1991, ApJ, 379, 631
Bournaud F., Elmegreen B. G., Elmegreen D. M., 2007, ApJ, 670, 237
Bureau M., Freeman K. C., 1999, AJ, 118, 126
Burton W. B., Liszt H. S., 1993, A&A, 274, 765
Cabrera-Lavers A., Hammersley P. L., González-Fernández C., López-Corredoira M., Garzón F., Mahoney T. J., 2007, A&A, 465, 825
Cao L., Mao S., Nataf D., Rattenbury N. J., Gould A., 2013, MNRAS, 434, 595
Cappellari M. et al., 2006, MNRAS, 366, 1126
Clarkson W. et al., 2008, ApJ, 684, 1110
Clarkson W. I. et al., 2011, ApJ, 735, 37
Combes F., Debbasch F., Friedli D., Pfenniger D., 1990, A&A, 233, 82
Dame T. M., Hartmann D., Thaddeus P., 2001, ApJ, 547, 792
de Lorenzi F., Debattista V. P., Gerhard O., Sambhus N., 2007, MNRAS, 376, 71
de Lorenzi F. et al., 2009, MNRAS, 395, 76
de Lorenzi F., Gerhard O., Saglia R. P., Sambhus N., Debattista V. P., Pannella M., Méndez R. H., 2008, MNRAS, 385, 1729
De Propris R. et al., 2011, ApJ, 732, L36
de Vaucouleurs G., 1964, in IAU Symposium, Vol. 20, The Galaxy and the Magellanic Clouds, Kerr F. J., ed., p. 195
Debattista V. P., Shen J., 2007, ApJ, 654, L127
Dehnen W., 2009, MNRAS, 395, 1079
Di Matteo P. et al., 2014, ArXiv e-prints
Elmegreen B. G., Bournaud F., Elmegreen D. M., 2008, ApJ, 688, 67
Elmegreen D. M., Elmegreen B. G., Hirst A. C., 2004, ApJ, 604, L21
Englmaier P., Gerhard O., 1999, MNRAS, 304, 512
Erwin P., Sparke L. S., 2002, AJ, 124, 65
Erwin P., Sparke L. S., 2003, ApJS, 146, 299
Freeman K. et al., 2013, MNRAS, 428, 3660
Freeman K. C., 2008, in IAU Symposium, Vol. 245, IAU Symposium, Bureau M., Athanassoula E., Barbuy B., eds., pp. 3–10
Fulbright J. P., McWilliam A., Rich R. M., 2007, ApJ, 661, 1152
Fux R., 1997, A&A, 327, 983
Fux R., 1999, A&A, 345, 787
Gardner E., Debattista V. P., Robin A. C., Vásquez S., Zoccali M., 2014, MNRAS, 438, 3275
Gerhard O., 2010, Highlights of Astronomy, 15, 198
Gerhard O., 2014, ArXiv:1408.0218
Gerhard O., Martinez-Valpuesta I., 2012, ApJ, 744, L8
Gilmore G. et al., 2012, The Messenger, 147, 25
Gonzalez O. A., Rejkuba M., Minniti D., Zoccali M., Valenti E., Saito R. K., 2011a, A&A, 534, L14
Gonzalez O. A. et al., 2011b, A&A, 530, A54
Gonzalez O. A., Rejkuba M., Zoccali M., Valent E., Minniti D., Tobar R., 2013, A&A, 552, A110
Guedes J., Mayer L., Carollo M., Madau P., 2013, ApJ, 772, 36
Häfner R., Evans N. W., Dehnen W., Binney J., 2000, MNRAS, 314, 433
Hill V. et al., 2011, A&A, 534, A80
Howard C. D. et al., 2009, ApJ, 702, L153
Howard C. D., Rich R. M., Reitzel D. B., Koch A., De Propris R., Zhao H., 2008, ApJ, 688, 1060
Howes L. M. et al., 2014, MNRAS, 445, 4241
Hunt J. A. S., Kawata D., 2013, MNRAS, 430, 1928
Hunt J. A. S., Kawata D., Martel H., 2013, MNRAS, 432, 3062
Immeli A., Samland M., Gerhard O., Westera P., 2004a, A&A, 413, 547
Immeli A., Samland M., Westera P., Gerhard O., 2004b, ApJ, 611, 20
Inoue S., Saitoh T. R., 2012, MNRAS, 422, 1902
Johnson C. I., Rich R. M., Fulbright J. P., Valenti E., McWilliam A., 2011, ApJ, 732, 108
Johnson C. I., Rich R. M., Kobayashi C., Fulbright J. P., 2012, ApJ, 749, 175
Johnson C. I., Rich R. M., Kobayashi C., Kunder A., Pilachowski C. A., Koch A., de Propris R., 2013, ApJ, 765, 157
Kobayashi C., 2014, in IAU Symposium, Vol. 298, IAU Symposium, Feltzing S., Zhao G., Walton N. A., Whitelock P., eds., pp. 167–178
Kormendy J., 1993, in IAU Symposium, Vol. 153, Galactic Bulges, Dejonghe H., Habing H. J., eds., p. 209
Kormendy J., Drory N., Bender R., Cornell M. E., 2010, ApJ, 723, 54
Kormendy J., Kennicutt, Jr. R. C., 2004, ARA&A, 42, 603
Kunder A. et al., 2012, AJ, 143, 57
Launhardt R., Zylka R., Mezger P. G., 2002, A&A, 384, 112
Laurikainen E., Salo H., Athanassoula E., Bosma A., Herrera-Endoqui M., 2014, MNRAS, 444, L80
Lecureur A., Hill V., Zoccali M., Barbuy B., Gómez A., Minniti D., Ortolani S., Renzini A., 2007, A&A, 465, 799
Li Z., Gerhard O., Shen J., et al., 2015, ApJ, in preparation
Li Z.-Y., Shen J., 2012, ApJ, 757, L7
Li Z.-Y., Shen J., 2015, ApJ, in preparation
Li Z.-Y., Shen J., Rich R. M., Kunder A., Mao S., 2014, ApJ, 785, L17
Long R. J., Mao S., 2010, MNRAS, 405, 301
Long R. J., Mao S., 2012, MNRAS, 421, 2580
Long R. J., Mao S., Shen J., Wang Y., 2013, MNRAS, 428, 3478
Martinez-Valpuesta I., Gerhard O., 2011, ApJ, 734, L20
Martinez-Valpuesta I., Gerhard O., 2013, ApJ, 766, L3
Martinez-Valpuesta I., Shlosman I., Heller C., 2006, ApJ, 637, 214
McWilliam A., Rich R. M., 1994, ApJS, 91, 749
McWilliam A., Zoccali M., 2010, ApJ, 724, 1491
Meléndez J. et al., 2008, A&A, 484, L21
Minniti D., Zoccali M., 2008, in IAU Symposium, Vol. 245, IAU Symposium, Bureau M., Athanassoula E., Barbuy B., eds., pp. 323–332
Morganti L., Gerhard O., 2012, MNRAS, 422, 1571
Nataf D. M., Cassisi S., Athanassoula E., 2014, MNRAS, 442, 2075
Nataf D. M., Udalski A., Gould A., Fouqué P., Stanek K. Z., 2010, ApJ, 721, L28
Nataf D. M. et al., 2015, MNRAS, 447, 1535
Ness M., Debattista V. P., Bensby T., Feltzing S., Roškar R., Cole D. R., Johnson J. A., Freeman K., 2014, ApJ, 787, L19
Ness M. et al., 2013a, MNRAS, 430, 836
Ness M. et al., 2013b, MNRAS, 432, 2092
Ness M. et al., 2012, ApJ, 756, 22
Nidever D. L. et al., 2012, ApJ, 755, L25
Nishiyama S. et al., 2005, ApJ, 621, L105
Noguchi M., 1999, ApJ, 514, 77
Obreja A., Domínguez-Tenreiro R., Brook C., Martínez-Serrano F. J., Doménech-Moral M., Serna A., Mollá M., Stinson G., 2013, ApJ, 763, 26
Origlia L., 2014, in IAU Symposium, Vol. 298, IAU Symposium, Feltzing S., Zhao G., Walton N. A., Whitelock P., eds., pp. 28–39
Ortolani S., Renzini A., Gilmozzi R., Marconi G., Barbuy B., Bica E., Rich R. M., 1995, Nature, 377, 701
Patsis P. A., Katsanikas M., 2014a, MNRAS, 445, 3525
Patsis P. A., Katsanikas M., 2014b, MNRAS, 445, 3546
Patsis P. A., Skokos C., Athanassoula E., 2002, MNRAS, 337, 578
Peebles P. J. E., Nusser A., 2010, Nature, 465, 565
Pfenniger D., Friedli D., 1991, A&A, 252, 75
Pfenniger D., Norman C., 1990, ApJ, 363, 391
Pietrukowicz P. et al., 2014, ArXiv:1412.4121
Poleski R. et al., 2013, ApJ, 776, 76
Portail M., Wegg C., Gerhard O., 2015b, MNRAS, 450, 66
Portail M., Wegg C., Gerhard O., Martinez-Valpuesta I., 2015a, MNRAS, 448, 713
Qin Y., Shen J., Li Z.-Y., Mao S., Smith M. C., Rich R. M., Kunder A., Liu C., 2015, ArXiv:1503.06774
Quillen A. C., Minchev I., Sharma S., Qin Y.-J., Di Matteo P., 2014, MNRAS, 437, 1284
Raha N., Sellwood J. A., James R. A., Kahn F. D., 1991, Nature, 352, 411
Rangwala N., Williams T. B., Stanek K. Z., 2009, ApJ, 691, 1387
Rattenbury N. J., Mao S., Debattista V. P., Sumi T., Gerhard O., de Lorenzi F., 2007a, MNRAS, 378, 1165
Rattenbury N. J., Mao S., Sumi T., Smith M. C., 2007b, MNRAS, 378, 1064
Rich R. M., 2013, The Galactic Bulge, Oswalt T. D., Gilmore G., eds., p. 271
Rich R. M., Howard C., Reitzel D. B., Zhao H., de Propris R., 2008, in IAU Symposium, Vol. 245, IAU Symposium, Bureau M., Athanassoula E., Barbuy B., eds., pp. 333–338
Rich R. M., Origlia L., Valenti E., 2012, ApJ, 746, 59
Rich R. M., Reitzel D. B., Howard C. D., Zhao H., 2007, ApJ, 658, L29
Richstone D. O., Tremaine S., 1988, ApJ, 327, 82
Robin A. C., Marshall D. J., Schultheis M., Reylé C., 2012, A&A, 538, A106
Robin A. C., Reylé C., Picaud S., Schultheis M., 2005, A&A, 430, 129
Rodriguez-Fernandez N. J., Combes F., 2008, A&A, 489, 115
Rojas-Arriagada A., Recio-Blanco A., Hill V., 2014, A&A, 569, A103
Saha K., Martinez-Valpuesta I., Gerhard O., 2012, MNRAS, 421, 333
Saito R. K., Zoccali M., McWilliam A., Minniti D., Gonzalez O. A., Hill V., 2011, AJ, 142, 76
Schlaufman K. C., Casey A. R., 2014, ApJ, 797, 13
Schwarzschild M., 1979, ApJ, 232, 236
Sellwood J. A., 2014, Reviews of Modern Physics, 86, 1
Sevenster M., Saha P., Valls-Gabaud D., Fux R., 1999, MNRAS, 307, 584
Shen J., 2014, in IAU Symposium, Vol. 298, IAU Symposium, Feltzing S., Zhao G., Walton N. A., Whitelock P., eds., pp. 201–206
Shen J., Debattista V. P., 2009, ApJ, 690, 758
Shen J., Rich R. M., Kormendy J., Howard C. D., De Propris R., Kunder A., 2010, ApJ, 720, L72
Shen J., Sellwood J. A., 2004, ApJ, 604, 614
Silverman B. W., 1986, Density estimation for statistics and data analysis
Skokos C., Patsis P. A., Athanassoula E., 2002, MNRAS, 333, 847
Soderblom D. R., 2010, ARA&A, 48, 581
Soto M., Rich R. M., Kuijken K., 2007, ApJ, 665, L31
Stanek K. Z., Garnavich P. M., 1998, ApJ, 503, L131
Stanek K. Z., Udalski A., SzymaŃski M., KaŁuŻny J., Kubiak Z. M., Mateo M., KrzemiŃski W., 1997, ApJ, 477, 163
Syer D., Tremaine S., 1996, MNRAS, 282, 223
Thomas J., Saglia R. P., Bender R., Thomas D., Gebhardt K., Magorrian J., Corsini E. M., Wegner G., 2005, MNRAS, 360, 1355
Toomre A., 1966, in Geophysical Fluid Dynamics, notes on the 1966 Summer Study Program at the Woods Hole Oceanographic Institution, ref. no. 66–46, p. 111
Uttenthaler S., Schultheis M., Nataf D. M., Robin A. C., Lebzelter T., Chen B., 2012, A&A, 546, A57
Vásquez S. et al., 2013, A&A, 555, A91
Wang Y., Mao S., Long R. J., Shen J., 2013, MNRAS, 435, 3437
Wang Y., Zhao H., Mao S., Rich R. M., 2012, MNRAS, 427, 1429
Wegg C., Gerhard O., 2013, MNRAS, 435, 1874
Weiland J. L. et al., 1994, ApJ, 425, L81
Wyse R. F. G., 1999, in The Formation of Galactic Bulges, Carollo C. M., Ferguson H. C., Wyse R. F. G., eds., p. 195
Zhao H., 1996, MNRAS, 283, 149
Zoccali M., 2010, in IAU Symposium, Vol. 265, IAU Symposium, Cunha K., Spite M., Barbuy B., eds., pp. 271–278
Zoccali M. et al., 2014, A&A, 562, A66
Zoccali M., Hill V., Lecureur A., Barbuy B., Renzini A., Minniti D., Gómez A., Ortolani S., 2008, A&A, 486, 177
Zoccali M. et al., 2003, A&A, 399, 931
Acknowledgements
We thank Shude Mao, Dimitri Gadotti, Eija Laurikainen, Zhi Li, Richard Long, Martin Smith, and Yu-jing Qin for helpful discussions and comments. The research presented here is partially supported by the 973 Program of China under grant no. 2014CB845700, by the National Natural Science Foundation of China under grant nos.11333003, 11322326, 11403072, and by the Strategic Priority Research Program “The Emergence of Cosmological Structures” (no. XDB09000000) of the Chinese Academy of Sciences. ZYL is grateful for the support from Shanghai Yangfan Talent Youth Program (No. 14YF1407700). This work made use of the facilities of the Center for High Performance Computing at Shanghai Astronomical Observatory.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Shen, J., Li, ZY. (2016). Theoretical Models of the Galactic Bulge. In: Laurikainen, E., Peletier, R., Gadotti, D. (eds) Galactic Bulges. Astrophysics and Space Science Library, vol 418. Springer, Cham. https://doi.org/10.1007/978-3-319-19378-6_10
Download citation
DOI: https://doi.org/10.1007/978-3-319-19378-6_10
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-19377-9
Online ISBN: 978-3-319-19378-6
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)