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Paper: The Galactic Structure and Stellar Population in the CFHTLS Wide Fields
Volume: 446, Galaxy Evolution: Infrared to Millimeter Wavelength Perspective
Page: 169
Authors: Xiao, Q. B.; Shu, C. G.; Luo, Z. J.; Shao, Z. Y.; Shen, S. Y.
Abstract: Using the star counts from the CFHTLS (Canada-France-Hawaii Telescope Legacy Survey) release T0005, we individually investigate the Milky Way structure in each of the four wide fields. Both for the thin- and thick-disk, we adopt a double exponential model and fit the stars with g'–r' > 1.0 to determine their scale heights. The best-fittings give a similar thin-disk model of the scale heights H1220 pc in all fields. The scale heights of the thick-disk are about 700 pc in all fields. The local space number density normalization of the thick-disk is 6.2% – 11.9% of the thin disk. Given the binary fraction ƒm = 35%, the corrected scale heights of the thin- and thick-disk and the thick-to-thin disk density normalization is 260 pc, 860 pc and 10%, respectively. For the halo, the stellar density distribution is modeled as a power law. We fixed the disk parameters and estimate the structure of stellar halo based on all stars in each wide field. The results give a sharp (large power index: n>2.8) and round (large axial ratio: c/a > 0.8) halo. We find that it is difficulty to well constrain the stellar halo by a single power law, and a “dual-halo” model is needed to describe the density distribution of the stellar halo.
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