VLA observations of the high-velocity bipolar OH absorption in L1551

Abstract

The VLA was used to map the high-velocity 1667 MHz OH absorption in L1551. The OH shows the same bipolar geometry seen in CO. The OH absorption is detected along the NW edge of the SW lobe and along the SE edge of the NE lobe, indicating that the high-velocity OH is located in the walls of the bipolar cavities created by the wind of L1551 IRS 5. The OH is detected only at the end of the bipolar lobes. It is suggested that this peculiar spatial distribution is due to an OH enhancement in the outer parts of the outflow as shock-produced H2O is photodissociated by the interstellar UV radiation field. 28 references.