Empirical extinction coefficients for the GALEX, SDSS, 2MASS and WISE
  passbands
  Using the "standard pair" technique of paring stars of almost nil and high
extinction but otherwise of almost identical stellar parameters from the SDSS,
and combing the SDSS, GALEX, 2MASS and WISE photometry ranging from the far UV
to the mid-IR, we have measured dust reddening in the FUV-NUV, NUV-u, u-g, g-r,
r-i, i-z, z-J, J-H, H-Ks, Ks-W1 and W1-W2 colors for thousands of Galactic
stars. The measurements, together with the E(B-V) values given by Schlegel et
al. (1998), allow us to derive the observed, model-free reddening coefficients
for those colors. The results are compared with previous measurements and the
predictions of a variety of Galactic reddening laws. We find that 1) The dust
reddening map of Schlegel et al. (1998) over-estimates E(B-V) by about 14 per
cent, consistent with the recent work of Schlafly et al. (2010) and Schlafly &
Finkbeiner (2011); 2) All the new reddening coefficients, except those for
NUV-u and u-g, prefer the R(V) = 3.1 Fitzpatrick reddening law rather than the
R(V) = 3.1 CCM and O'Donnell (O'Donnell 1994) reddening laws. Using the Ks-band
extinction coefficient predicted by the R(V) = 3.1 Fitzpatrick law and the
observed reddening coefficients, we have deduced new extinction coefficients
for the FUV, NUV, u, g, r, i, z, J, H, W1 and W2 passbands. We recommend that
the new reddening and extinction coefficients should be used in the future and
an update of the Fitzpatrick reddening law in the UV is probably necessary. We
stress however that the FUV- and NUV-band coefficients should be used with
caution given their relatively large measurement uncertainties. Finally,
potential applications of the "standard pair" technique with the LAMOST
Galactic surveys are discussed.
