SIMBAD references

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 3 arcmin. We measured the cloud distances by comparing the observed density of foreground stars with the prediction of galactic models, thus obtaining dOrion A=(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.