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We present subarcsecond observations toward the massive star-forming region G75.78+0.34. We used the Very Large Array to study the centimeter continuum and H2O and CH3OH maser emission, and the Owens Valley Radio Observatory and Submillimeter Array to study the millimeter continuum and recombination lines (H40α and H30α). We found radio continuum emission at all wavelengths, coming from three components: (1) a cometary ultracompact (UC) Hii region with an electron density ~3.7 × 104 cm-3, excited by a B0 type star, and with no associated dust emission; (2) an almost unresolved UCHii region (EAST), located ~6'' to the east of the cometary UCHii region, with an electron density ~1.3 × 105 cm-3, and associated with a compact dust clump detected at millimeter and mid-infrared wavelengths; and (3) a compact source (CORE), located ~2'' to the southwest of the cometary arc, with a flux density increasing with frequency, and embedded in a dust condensation of 30 M☉. The CORE source is resolved into two compact and unresolved sources which can be well fit by two homogeneous hypercompact Hii regions each one photoionized by a B0.5 zero-age main sequence star, or by free-free radiation from shock-ionized gas resulting from the interaction of a jet/outflow system with the surrounding environment. The spatial distribution and kinematics of water masers close to the CORE-N and S sources, together with excess emission at 4.5μm and the detected dust emission, suggest that the CORE source is a massive protostar driving a jet/outflow. [ABSTRACT FROM AUTHOR]

We present high-resolution 1.3 mm continuum observations of the massive young stellar object S140-IRS1. S140-IRS1 is a disc wind prototype with elongated radio emission (PA ∼ 45°) perpendicular to the large-scale CO outflow in the region. The observations taken with the CARMA B array and the Submillimetre Array (SMA) compact configuration correspond to a spatial resolution of 0.3 and 3.0 arcsec, respectively. Complementary 2.7 and 3.5 mm data taken with OVRO in a compact configuration are also discussed. The deconvolved position angle for S140-IRS1 of 37° ±15° is compatible with a disc perpendicular to the main CO outflow and near-infrared monopolar reflection nebula. We have utilized two-dimensional axisymmetric radiative transfer modelling to interpret the millimetre wave emission from S140-IRS1. The model required the addition of a disc component, as the observed image, flux and visibilities cannot be represented solely by a dusty envelope with polar cavities. We report that the high-resolution image of S140-IRS1 is consistent with the interpretation of emission from a dust disc in a large-scale envelope with cleared bipolar cavities. Strong continuum emission is also detected in both SMA and OVRO maps from the previously discovered submillimetre source S140-SMM1 and from the infrared source S140-IRS3. Furthermore, S140-SMM1 is identified with maser sources whose proper motions are consistent with being the source of the outflow with position angle ∼20° previously associated by some authors with a second outflow created by S140-IRS1. Our findings are consistent with a disc wind interpretation of the radio emission for S140-IRS1 rather than that of a jet. [ABSTRACT FROM PUBLISHER]

Optical, infrared and radio (single dish and interferometric) observations of jets and outflows from newly formed stars have helped to improve our understanding of molecular outflows and the outflow/accretion connection. However, once the Atacama Large Millimeter Array (ALMA) is completed, it will provide a significant increase in sensitivity and resolution at millimeter and sub-millimeter wavelengths that will allow astronomers to address critical issues that cannot be explored with established observatories. Of particular importance is that ALMA will recover both extended and compact emission from the large scale molecular cloud and outflows to compact cores and disks. Thus, we will be able to study the detailed kinematics of the outflows, entrainment properties, momentum transfer and feedback, and collimation. I will review our current observational limitations and provide examples of how ALMA will contribute to the study of molecular outflows in star forming regions. [ABSTRACT FROM AUTHOR]