The ionization of accretion flows in high-mass star formation: W51e2

Previous observations show that the hypercompact H II region W51e2 is surrounded by a massive molecular accretion flow centered on the H II region. New observations of the H53 alpha radio recombination line made with the VLA at 0.45'' angular resolution show a velocity gradient in the ionized gas within the H II region of 1500 km s(-1) pc(-1) comparable to the velocity gradient seen in the molecular accretion flow. New CO line observations made with the SMA at arcsecond angular resolution detect a molecular bipolar outflow immediately around the W51e2 H II region and extending along the axis of rotation of the molecular flow. These observations are consistent with an evolutionary phase of high-mass star formation in which a newly formed massive star first begins to ionize its surroundings including its own accretion flow.