1999PASP..111.1088K

We present a spectral line image in CO (J=7-6) of the spatially compact molecular outflow from the massive protostar IRAS 20126+4014, observed using a novel superconductive hot-electron bolometer (HEB) heterodyne receiver we recently installed at the 10 m Heinrich Hertz Telescope. The bipolar outflow is clearly detected and resolved with a center of symmetry situated at the position of the massive protostar, previously identified as an IRAS source and a millimeter continuum source. The peaks of the emission from the red- and blueshifted CO lobes are separated by ~14" (0.1 pc), and the velocity of the CO emission extends ±30 km.s^–1 from the ambient cloud velocity. The total outflowing gas mass is approximately 4 M_☉, while the outflow rate is at least 6x10^–4 M_☉ yr^–1. Both high-velocity CO emission maxima trail the NH₃ (3, 3) and SiO clumps located 3"-4" downstream (farther from the IR source) in the flow. The high-excitation CO line and the NH₃ are likely tracing the heated gas entrained in different parts of the bow shocks. By interpreting our observations in terms of a jet-driven model, we estimate the density in the underlying jet to be at least 10⁵ cm^–3. The outflow appears much more compact and in a different orientation than the arcminute-scale north/south flow seen in low-J transitions of CO. These observations represent the first successful operation of a superconductive HEB receiver on a telescope and demonstrate the importance of high-frequency submillimeter lines to the understanding of the protostellar environment.