Galactic Parameters from Whole Sky 2MASS Star Count

C. K. Chang; C. M. Ko; T. H. Peng

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arXiv · 0811.3269

Galactic Parameters from Whole Sky 2MASS Star Count

C. K. Chang·C. M. Ko·T. H. Peng

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Abstract

The whole sky differential star counts (DSC) with 1 degree resolution are retrieved from 2MASS online data service. Galaxy with double exponential thin and thick disks and a single power law luminosity function (LF) is used to interpret the 2MASS data. The slope of the DSC appears roughly isotropic over the whole sky, the average value is ~0.32, which corresponds to a power law index ~1.8 of the LF. We find that the scale-length and scale-height the thin disk are ~3.0 kpc and ~245 pc, and those of the thick disk are ~3.0 kpc and ~780 pc. The ratio of the thick disk to the thin disk is ~7%. The location of Sun above the disk is ~15 pc. A comparison of the data and model and their discrepancy are also provided.

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BibTeX RIS

C. K. Chang, C. M. Ko, T. H. Peng. 2008-11-20. Galactic Parameters from Whole Sky 2MASS Star Count. https://arxiv.org/abs/0811.3269

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