The color gradients of spiral disks in the Sloan Digital Sky Survey - Astrophysics > Cosmology and Nongalactic AstrophysicsReportar como inadecuado




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Abstract: We investigate the radial color gradients of galactic disks using a sample ofabout 20,000 face-on spiral galaxies selected from the fourth data release ofthe Sloan Digital Sky Survey SDSS-DR4. We combine galaxies with similarconcentration, size and luminosity to construct composite galaxies, and thenmeasure their color profiles by stacking the azimuthally averaged radial colorprofiles of all the member galaxies. Except for the smallest galaxies R {50}<3kpc, almost all galaxies show negative disk color gradients with mean g-rgradient G {gr}=-0.006 mag kpc^{-1} and r-z gradient G {rz}=-0.018 magkpc^{-1}. The disk color gradients are independent of the morphological typesof galaxies and strongly dependent on the disk surface brightness \mu {d}, withlower surface brightness galactic disks having steeper color gradients. Wequantify the intrinsic correlation between color gradients and surfacebrightness as G {gr}=-0.011\mu {d}+0.233 and G {rz}=-0.015\mu {d}+0.324. Thesequantified correlations provide tight observational constraints on theformation and evolution models of spiral galaxies.



Autor: C.Z. Liu, S.Y. Shen, Z.Y. Shao, R.X. Chang, J.L. Hou, J. Yin, D.W. Yang

Fuente: https://arxiv.org/







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