2014ApJS..211...18K

In our multi-epoch observation of the star-forming region NGC 2264 with the VLBI Exploration of Radio Astrometry, we detected two water maser features. We have measured the annual parallax of the maser sources for the first time in NGC 2264 and derived 1.356±0.098 mas, corresponding to the distance of 738_–50⁺⁵⁷ pc, which is consistent with its previously reported photometric observations. One of the maser features is located near a dust continuum core, CMM4S, positionally corresponding to the X-ray source FMS2-1269 listed in Flaccomio et al. Re-analyzing Chandra X-ray data, we found that FMS2-1269 is still surrounded by a dense envelope of a H₂ column density, 5.4x10²³/cm2. We suggest that the maser detected near the CMM4S core is most likely associated with the X-ray-emitting Class 0 candidate FMS2-1269. The other maser feature is found to emerge from a high-velocity outflow of 150 km/s and is associated with the 3.6 cm radio continuum source NGC 2264 VLA 3 located close to IRS1.