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Galactic longitude dependent Galactic model parameters

  • Bilir, S.
  • Karaali, S.
  • Ak, S.
  • Yaz, E.
  • Hamzaoglu, E.
Published Article
Publication Date
Oct 04, 2006
Submission Date
Oct 04, 2006
DOI: 10.1016/j.newast.2006.10.001
arXiv ID: astro-ph/0610109
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We present the Galactic model parameters for thin disc estimated by Sloan Digital Sky Survey (SDSS) data of 14 940 stars with apparent magnitudes $16<g_{o}\leq21$ in six intermediate latitude fields in the first Galactic quadrant. Star/galaxy separation was performed by using the $SDSS$ photometric pipeline and the isodensity contours in the $(g-r)_{0}-(r-i)_{0}$ two colour diagram. The separation of thin disc stars is carried out by the bimodal distribution of stars in the $(g-r)_{o}$ histogram, and the absolute magnitudes were evaluated by a procedure presented in the literature Bilir et al. (2005). Exponential density law fits better to the derived density functions for the absolute magnitude intervals $8<M(g)\leq9$ and $11<M(g)\leq12$, whereas sech/sech$^{2}$ laws are more appropriate for absolute magnitude intervals $9<M(g)\leq10$ and $10<M(g)\leq11$. We showed that the scaleheight and scalelength are Galactic longitude dependent. The average values and ranges of the scaleheight and the scalelength are $<H>=220$ pc ($196\leq H \leq 234$ pc) and $<h>=1900$ pc ($1561\leq h \leq 2280$ pc) respectively. This result would be useful to explain different numerical values claimed for those parameters obtained by different authors for the fields in different directions of the Galaxy.

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