2008ApJ...680.1174N

We have determined the ratios of total to selective extinction directly from observations in the optical V band and near-infrared J band toward the Galactic center. The OGLE (Optical Gravitational Lensing Experiment) Galactic bulge fields have been observed with the SIRIUS camera on the Infrared Survey Facility telescope, and we obtain A_V/E_V-J_=1.251±0.014 and A_J/E_V-J_=0.225±0.007. From these ratios, we derive A_J/A_V=0.188±0.005; combining this with the near-infrared extinction ratios obtained in Paper I for more reddened fields near the Galactic center, we obtain A_V_:A_J:A_H:A_Ks=1:0.188:0.108:0.062, which implies steeply declining extinction toward longer wavelengths. In particular, it is striking that the K_s-band extinction is ~1/16 the visual extinction A_V, much smaller than the 1/10 usually employed.