Observations of Molecular Clouds in the HH 1–2 Region

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Abstract
We observed the region of Herbig-Haro object HH 1-2 with several molecular lines. The emission is dominated by two large-scale (~150'') elongations roughly parallel to each other in the HCO+ J = 3 → 2 line map. We discuss our results testing the two possibilities suggested in the literature: a molecular toroid around VLA 1, as suggested by Torrelles et al. (1994), and two physically disconnected elongations, as suggested by Cernicharo (1991). Around the central source, VLA 1, our HCO+ J = 4 → 3 and H2CO JK−1K+ 1=303→202 maps all show a ~40'' scale elongation nearly perpendicular to the HH 1-2 axis. We suggest that this molecular core is a disk/toroid-like structure. Our CO J = 3 → 2 data reveal the existence of a molecular outflow around VLA 1. We also observed an HCO+ clump downwind of HH 2, where the HCO+ abundance is possibly enhanced by the shock. We also discuss the star formation activities around VLA 3.