Extinction in the large magellanic cloud

We present an extinction map of the Large Magellanic Cloud ( LMC), using 204,502 stars from the Two Micron All-Sky Survey point-source catalog. We first use the NICE method to determine the reddening distribution, E( H - K) and E( J - H), which we compare to the H I distribution to find a near-infrared reddening law of E( J - H)/E( H - K) 1.20 +/- 0.04. A visual extinction map ( similar to 6 degrees x 6 degrees) of the LMC is created using the NICER method; at 4' resolution, a mean value of A(V) = 0.3 mag is found. We derive the LMC CO-to-H-2 conversion factor, X-LMC, independent of assumptions about the virialization of giant molecular clouds, by comparing the NICER extinction map with NANTEN (CO)-C-12 observations. In regions where A(V) > 1 mag and (CO)-C-12 emission is >= 2 K km s(-1), we measure X-LMC = 9.3 +/- 0.4 x 10(20) cm(-2) ( K km s(-1))(-1). In the same regions, the LMC contains a total molecularmass of ( 4.5 +/- 0.2) x 10(7) M-circle dot.