Universality of the Near-Infrared Extinction Law Based on the APOGEE
  Survey
  Whether the near-infrared (NIR) extinction law is universal has been a long
debated topic. Based on the APOGEE H-band spectroscopic survey as a key project
of SDSS-III, the intrinsic colors of a large number of giant stars are
accurately determined from the stellar effective temperature. Taking this
advantage and using a sample of 5942 K-type giants, the NIR extinction law is
carefully re-visited. The color excess ratio E(J-H)/E(J-Ks), representative of
the NIR extinction law, shows no dependence on the color excess when E(J-Ks)
changes from ~0.3 to ~4.0, which implies a universal NIR extinction law from
diffuse to dense regions. The constant value of E(J-H)/E(J-Ks), 0.64,
corresponds to a power law index of 1.95. The other two ratios, E(H-Ks)/E(J-Ks)
and E(J-H)/E(H-Ks), are 0.36 and 1.78 respectively. The results are consistent
with the MRN dust size distribution.
