SIMBAD references

The young stellar object SVS 13 is believed to power the chain formed by the HH 7-11 objects. Recent observations have revealed that in the radio continuum (3.6-cm) the source is a binary with components separated by about 0.3" in the east-west direction. The members of the binary are named VLA 4A (western component) and VLA 4B (eastern component). In an attempt to ascertain which of the two components of the binary is the most likely candidate to drive the outflow, we obtained accurate positions for the H₂O maser spots toward this source, also known as H₂O(A), derived from Very Large Array observations in its highest angular resolution A configuration. We detected a total of eleven spots over four observational sessions (made in the years 1983, 1985, 1988, and 1989). The spots are segregated in two velocity groups: a velocity group with v_LSR similar to that of the ambient cloud (v_LSR ≃8km/s), for which we detected five features (with v_LSR in the range of 6.5 to 12.2km/s) and a blueshifted velocity group (six features with v_LSR in the range of -25.4 to -5.6km/s). Remarkably, all the spots in the first velocity group are associated with VLA 4A, while all the spots in the blueshifted velocity group are associated with VLA 4B. We discuss the possible implications of this observation. We also present accurate positions of the H₂O maser HH 7(B) and of the masers associated with IRAS4B (VLA 28) and IRAS7 (VLA 27, the exciting source of HH 6).