2MASS wide field extinction maps IV : The Orion, Monoceros R2, Rosette, and Canis Major star forming regions

We present a near-infrared extinction map of a large region (approximately 2200 deg2 ) covering the Orion, the Monoceros R2, the Rosette, and the Canis Major molecular clouds. We used robust and optimal methods to map the dust column density in the near-infrared (Nicer and Nicest) towards  ~19 million stars of the Two Micron All Sky Survey (2MASS) point source catalog. Over the relevant regions of the field, we reached a 1-σ error of 0.03 mag in the K -band extinction with a resolution of 3arcmin. We measured the cloud distances by comparing the observed density of foreground stars with the prediction of galactic models, thus obtaining d OrionA  = (371 ± 10) pc, d OrionB  = (398 ± 12) pc, d MonR2  = (905 ± 37) pc, d Rosette  = (1330 ± 48) pc, and d CMa  = (1150 ± 64) pc, values that compare very well with independent estimates.