OBSERVATIONS OF THE IR RECOMBINATION LINE EMISSION FROM MASSIVE YOUNGSTELLAR OBJECTS

We present new, high-resolution observations of the infrared H I emiss ion lines of massive YSOs. The widths of the Br alpha, Br gamma and Pf gamma lines indicate outflowing material with velocities of 100-200 k m s(-1) for all the sources observed. We discuss the morphology of the line profiles and examine the velocity-resolved line ratios. Three of the sources appear to be dominated by an expanding optically thick st ellar wind, whilst BN shows some evidence for an additional narrow, mo re optically thin component, as we found previously for S106IR. The ob ject M17 SW IRS1 has line profiles more like those of a Herbig Be star .