Current star formation theories (Forster & Caswell 1989, Genzel & Downes 1977) suggest that as a YSO forms from a massive protostar, H2O masers form near the core while OH masers form within the circumstellar material. For this reason, we chose to use half of our summer student observing time to look at the 6_16 - 5_23 maser transition in water molecules (22 GHz, 1.3 cm, K band). The water maser regions were chosen based on a study published in 1995 by G. Tofain et al. and suggested by an NRAO staff scientist, Greg Taylor.
As in the first epoch of observations by Tofani et al., the VLA is in A-configuration this summer. The first observation ran from 5:30 to 7:00 LST on 16 July 1999, during which we observed 4 sources: AFGL5142, S233, S235B and NGC2071. The second run observed these same four sources and four additional ones (NGC281W, AFGL5180, Mon-R2, GGD-4) from 4:30 to 7:30 LST on 22 July 1999. By self-calibrating and imaging the data in AIPS, we hope to pursue a study in the proper motions of these masers, thereby lending some insight into the molecular outflows in star-forming regions.
Questions? E-mail Colleen Schwartz.