Revolution in Astronomy with Alma: the Third Year

We present preliminary analysis of ALMA cycle 1 12m array CO /CO /CO data of the HH 46/47 molecular outflow. CO and CO trace relatively denser outflow material than CO and allow us to trace the outflow to lower velocities than what it possible using only the CO emission. Interestingly, the cavity wall of the red lobe can be seen at velocity as low as 0.2 km/s. Using CO, we are now able to estimate the optical depth of CO, and then use the corrected CO emission to further and better correct the CO emission and estimate the mass, momentum, and kinetic energy of the outflow. Moreover, CO reveals a flattened rotational structure at the center, likely to be a rotational envelope infalling onto an inner Keplerian disk. The outflow feedback on the protostellar core may be responsible for finally dispersing it and setting the core-to-star efficiency. Therefore it is crucial to accurately estimate the mass, momentum and kinetic energy of the outflow, especially at low velocities where the data often suffers from high CO opacities. Here we present ALMA cycle 1 12m array data of the HH 46/47 molecular outflow driven by a low-mass Class 0/I source at 450 pc. ALMA cycle 0 observations of CO(1-0) showed that the molecular outflow is formed by the entrainment of the gas by a jet and/or a wide-angle wind (Arce et al. 2013). CO and CO trace relatively denser and slower material than CO and are only detected within ∼1 km/s from the cloud velocity (Figure 1). This allows us to trace the outflow to lower velocities than what it possible using only the CO. Interestingly, the cavity wall of the red lobe can be seen at outflow velocity as low as ∼0.2 km/s. Furthermore, using CO we are able to study the dependence of the CO opacity on velocity. The second panel of Figure 2 shows the emission ratio between these tracers, which is close to 0 when optically thick, and reach the abundance ratio of two tracers when optically thin. We can see that CO is optically thick within ∼ 0.8 km/s. The corrected CO emission is then used to further and better correct the CO emission (first panel of Fig. 2) and estimate the mass spectrum of the outflow (right four panels). Such correction significantly increased the estimated outflow mass within about 4km/s. With the high sensitivity and resolution we actually are able to study such velocity dependence of opacities for each sub-region (central part, extended outflow, etc.). In addition, CO reveals a flattened rotational structure around the central source, likely to be a rotational envelope infalling onto an inner Keplerian disk. With the full data set (which includes 12m array, ACA and total power data of CO, CO and CO)