Interstellar Extinction Law in theJ,H, andKsBands toward the Galactic Center

We have determined the ratios of total to selective extinction in thenear-infrared bands (J, H, Ks) toward the Galactic center from the observationsof the region |l| < 2.0deg and 0.5deg < |b| < 1.0deg with the IRSF telescopeand the SIRIUS camera. Using the positions of red clump stars incolor-magnitude diagrams as a tracer of the extinction and reddening, wedetermine the average of the ratios of total to selective extinction to beA(Ks)/E(H-Ks) = 1.44+-0.01, A(Ks)/E(J-Ks) = 0.494+-0.006, and A(H)/E(J-H) =1.42+-0.02, which are significantly smaller than those obtained in previousstudies. From these ratios, we estimate that A(J) : A(H) : A(Ks) = 1 :0.573+-0.009 : 0.331+-0.004 and E(J-H)/E(H-Ks) = 1.72+-0.04, and we find thatthe power law A(lambda) \propto lambda^{-1.99+-0.02} is a good approximationover these wavelengths. Moreover, we find a small variation in A(Ks)/E(H-Ks)across our survey. This suggests that the infrared extinction law changes fromone line of sight to another, and the so-called ``universality'' does notnecessarily hold in the infrared wavelengths.Comment: 18 pages, 9 figures, Accepted for publication in the Ap