F. Hammer, M. Puech, H. Flores, Y. B. Yang, J. L. Wang, S. Fouquet
Cosmologists have often considered the Milky Way as a typical spiral galaxy,
and its properties have considerably influenced the current scheme of galaxy
formation. Here we compare the general properties of the Milky Way disk and
halo with those of galaxies selected from the SDSS. Assuming the recent
measurements of its circular velocity results in the Milky Way being offset by
~2 sigma from the fundamental scaling relations. On the basis of their location
in the (M_K, R_d, V_flat) volume, the fraction of SDSS spirals like the
MilkyWay is only 1.2% in sharp contrast with M31, which appears to be quite
typical. Comparison of the Milky Way with M31 and with other spirals is also
discussed to investigate whether or not there is a fundamental discrepancy
between their mass assembly histories. Possibly the Milky Way is one of the
very few local galaxies that could be a direct descendant of very distant,
z=2-3 galaxies, thanks to its quiescent history since thick disk formation.
View original:
http://arxiv.org/abs/1111.2044
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