VLA observations of the Herbig-Haro 1-2 system

We present a multifrequency, multiconfiguration of VLA study of the Herbig-Haro objects 1 and 2 and of their central source of energy. When observed with high angular resolution, the central source is elongated, and its major axis aligns within a few degrees with the HH 1-2 axis. The major axis of the central source is resolved at 20, 6, and 2 cm, while the minor axis remains unresolved at a scale of 0″.1. The deconvolved angular size of the major axis decreases with increasing frequency, θv ∝ v-0.7. This dependence of angular size with frequency, first reported here for the radio emission associated with a low-mass star, as well as the dependence of flux with frequency, Sv ∝ v0.3, favor a confined thermal jet nature for the central source. At high angular resolution, the radio continuum emission from both HH 1 and HH 2 is dominated by one component that we associate with the brightest optical subcondensation of each HH object, HH 1F and HH 2A′, respectively. Using radio data taken 2.3 yr apart, we have been able to measure the proper motion of HH 1F, obtaining μt = 21″ ± 4″ per century, in good agreement with the value measured in the optical by Herbig and Jones. In the case of HH 2A′, the proper motions are confused by the possible appearance of a new component upstream of the outflow. We also discuss the nature of other sources detected in the field.