Estimation of Galactic model parameters with the SDSS and metallicity distribution in two fields in the anti-centre direction of the Galaxy

Abstract

We estimated the Galactic model parameters from the SDSS data reduced for two fields in the anti-centre direction of the Galaxy, $l=180^o$, and symmetric relative to the Galactic plane, $b=+45^o$ and $b=-45^o$. The large size of each field, 60 deg${}^2$, and the faint limiting apparent magnitude, g=22, give us the chance to determine reliable parameters for three components, thin and thick discs and halo, in the north and south hemispheres of the Galaxy, except the scalelengths for two discs which are adopted from Jurić et al. (2005). Metallicities were evaluated by a recent calibration for SDSS, and absolute magnitudes of stars with $4<M(g)\le 8$ were derived as a function of (g-r) colour and metallicity. Conspicuous differences could not be detected between the corresponding Galactic model parameters for the thin disc of north and south fields, and our results are consistent with the ones in the literature. The same case is valid for the halo, especially the axis ratios for two fields are exactly equal, $\kappa =0.45$. The metallicity distribution for unevolved G type stars with $5<M(g)\le 6$ shows three substructures relative to the distance from the Galactic plane: for $z^{\ast }<3$ kpc, the metallicity gradient for two fields is $d[M/H]/dz\sim -0.20(\pm 0.02)$ dex kpc${}^{-1}$, consistent with the formation scenario of the thin disc. For $5<z^{\ast }<10$ kpc, $d[M/H]/dz\sim -0.03(\pm 0.001)$ dex kpc${}^{-1}$ for two fields, confirming that the metallicity gradient for the halo component is close to zero. When we combine these substructures, however, we find a smooth metallicity gradient for two fields, $-0.30(\pm 0.04)$ dex kpc${}^{-1}$.

12 pages, 6 figures and 4 tables, accepted for publication in Astronomische Nachrichten

References in corpus (19)

• The Sloan Digital Sky Survey Photometric Camera
• The u'g'r'i'z' Standard Star Network
• Astrometric Calibration of the Sloan Digital Sky Survey
• The Third Data Release of the Sloan Digital Sky Survey
• A photometricity and extinction monitor at the Apache Point Observatory
• Outer structure of the Galactic warp and flare: explaining the Canis Major over-density
• A Catalog of Spectroscopically Identified White Dwarf Stars in the First Data Release of the Sloan Digital Sky Survey
• Starcounts Redivivus. IV. Density Laws Through Photometric Parallaxes
• Colors of 2625 Quasars at 0<z<5 Measured in the Sloan Digital Sky Survey Photometric System
• Vertical scaleheights in a gravitationally coupled, three-component Galactic disk
• A Second Stellar Color Locus: a Bridge from White Dwarfs to M stars
• New colour-transformations for the Sloan photometry and revised metallicity calibration and equations for photometric parallax estimation
• A different approach for the estimation of Galactic model parameters
• Galactic structure studies with BATC star counts
• The investigation of ELAIS field by Vega photometry: Absolute - magnitude dependent on the Galactic model parameters
• A CCD Study of High Latitude Galactic Structure: Testing the Model Parameters
• Galactic structure studies from BATC survey
• The metallicity distribution of F/G dwarfs derived from BATC survey data
• Galactic structure from the Calar Alto Deep Imaging Survey (CADIS)

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• The stellar metallicity distribution of the Milky Way from the BATC survey
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