SIMBAD references

We obtained near-infrared (NIR) imaging with the Subaru Telescope of the class 0 protostar candidates in the Orion molecular cloud 3, two of which were discovered to have X-ray emission by the Chandra X-Ray Observatory . We found strong evidence for the class 0 nature of the X-ray sources. First, our deep K-band image shows no emission brighter than 19.6 mag from both of these X-ray sources. Since class I protostars or class II T Tauri stars should be easily detected in the NIR with this sensitivity, the lack of K-band detection suggests that they are likely much more obscured than class I protostars. Second, our H₂v=1-0S(1) image shows a bubble-like feature from one of the X-ray class 0 protostar candidates, which reinforces the idea that this is a class 0 protostar. We also discuss the nature of nine NIR sources found in our deep image based on their colors, spatial coincidence with millimeter cores, and the properties of their X-ray counterparts.