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A secularly evolved model for the Milky Way bar and bulge

Published online by Cambridge University Press:  05 March 2015

Inma Martinez-Valpuesta  and
Ortwin Gerhard
Inma Martinez-Valpuesta
Affiliation:
Max Planck Institute for Extraterrestrial Physics, 85748, Garching, Germany email: imv@mpe.mpg.de
Ortwin Gerhard
Affiliation:
Max Planck Institute for Extraterrestrial Physics, 85748, Garching, Germany email: imv@mpe.mpg.de
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Abstract

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Bars are strong drivers of secular evolution in disk galaxies. Bars themselves can evolve secularly through angular momentum transport, producing different boxy/peanut and X-shaped bulges. Our Milky Way is an example of a barred galaxy with a boxy bulge. We present a self-consistent N-body simulation of a barred galaxy which matches remarkably well the structure of the inner Milky Way deduced from star counts. In particular, features taken as signatures of a second “long bar“ can be explained by the interaction between the bar and the spiral arms of the galaxy (Martinez-Valpuesta & Gerhard 2011). Furthermore the structural change in the bulge inside l = 4° measured recently from VVV data can be explained by the high-density near-axisymmetric part of the inner boxy bulge (Gerhard & Martinez-Valpuesta 2012). We also compare this model with kinematic data from recent spectroscopic surveys. We use a modified version of the NMAGIC code (de Lorenzi et al. 2007) to study the properties of the Milky Way bar, obtaining an upper limit for the pattern speed of ~ 42 km/sec/kpc. See Fig. 1 for a comparison of one of our best models with BRAVA data (Kunder et al. 2012).

Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 10 , Highlights H16: Highlights of Astronomy , August 2012 , pp. 351
Copyright
Copyright © International Astronomical Union 2015 

References

de Lorenzi, F., Debattista, V. P., Gerhard, O., & Sambhus, N. 2007, MNRAS, 376, 71CrossRefGoogle Scholar
Kunder, A., Koch, A., Rich, R. M., et al. 2012, AJ, 143, 57Google Scholar
Gerhard, O. & Martinez-Valpuesta, I. 2012, ApJ, 744, L8CrossRefGoogle Scholar
Martinez-Valpuesta, I. & Gerhard, O. 2011, ApJ, 734, L20Google Scholar