Bipolar molecular outÑows are a basic component of the star formation process. This is true for stars of all masses, although it has not yet been well established how outÑows associated with massive stars di †er from those associated with low-mass stars. We present results from a project to identify bipolar outÑows from massive young stellar objects (YSOs) and determine how they compare with low-mass YSO systems. Ten massive star formation regions with high-velocity 12CO(J \ 1È0) line wings were mapped with the Kitt Peak 12 m telescope using the On-the-Fly (OTF) mapping technique. Five of the regions have bipolar outÑows. We determine accurate mass estimates of the molecular gas in the redand blueshifted lobes by taking into account variations in the optical depth as a function of velocity in the Ñow. We Ðnd that the molecular outÑows have masses between D16 and 72 and kinetic energies M _ between D1045 and 1046 ergs. The outÑows have signiÐcantly more mass and kinetic energy than those from low-mass YSOs. Of the remaining Ðve regions, two have a clumpy distribution in 12CO with multiple velocity components within the cloud complex, and three sources did not have sufficient signal-tonoise ratio (S/N) to map the high-velocity line wings. We combine our data with 18 additional outÑow sources with stellar luminosities that range from 0.6 to 2.1 ] 105 to predict the luminosity of the L _ L _ star responsible for the outÑow. We Ðnd that the stellar luminosities of the sources in our sample range from D102 to 104 which correspond to mid-to early-B type stars ; the precursors of Herbig Be L _ , stars. One source, G173.58, has an IRAS source on the Ñow axis with the appropriate luminosity to drive the observed outÑow. For the remaining four sources, there is no detectable ultracompact (UC) H II region or isolated IRAS source with the appropriate luminosity to produce the observed molecular outÑow. The outÑows mapped in this work begin to Ðll in a region of outÑow parameter space in which relatively few sources have been studied, and they help to bridge the gap between low-luminosity outÑow sources and the few isolated outÑows from massive O stars. Our data are consistent with the ideas that (1) in a molecular outÑow increases continuously with of the driving source over a range from M 0 L bol D1 to D106 (2) one can predict the central source luminosity from the measured mass Ñux in L _ L _ , the Ñow, (3) there is a clear versus age relationship for stars of all luminosities, and (4) the M flow (t d ) larger for higher luminosity sources implies that these objects produce massive outÑows on short M 0 timescales relative to low-mass stars.

ABSTRACT. Hi-GAL, the Herschel infrared Galactic Plane Survey, is an Open Time Key Project of the Herschel Space Observatory. It will make an unbiased photometric survey of the inner Galactic plane by mapping a 2°wide strip in the longitude range |l| < 60°in five wavebands between 70 μm and 500 μm. The aim of Hi-GAL is to detect the earliest phases of the formation of molecular clouds and high-mass stars and to use the optimum combination of Herschel wavelength coverage, sensitivity, mapping strategy, and speed to deliver a homogeneous census of starforming regions and cold structures in the interstellar medium. The resulting representative samples will yield the variation of source temperature, luminosity, mass and age in a wide range of Galactic environments at all scales from massive YSOs in protoclusters to entire spiral arms, providing an evolutionary sequence for the formation of intermediate and high-mass stars. This information is essential to the formulation of a predictive global model of the role of environment and feedback in regulating the star-formation process. Such a model is vital to understanding star formation on galactic scales and in the early universe. Hi-GAL will also provide a science legacy for decades to come with incalculable potential for systematic and serendipitous science in a wide range of astronomical fields, enabling the optimum use of future major facilities such as JWST and ALMA.

We present images of the molecular gas in the IRAS 20126]4104 massive outÑow and examine the interaction between the energetic outÑowing material and the surrounding molecular cloud. Mosaic interferometric images in CO(1È0), 13CO(1È0), C18O(1È0), C17O(1È0), and millimeter continuum emission are compared with mid-infrared images at 12.5 and 17.9 km, near-infrared images in the band K s (2.17 km) and line emission, and optical Ha and [S II] images. We show that the molecular outÑow H 2 is approximately 6 ] 104 yr old with a mass of about 50È60and mass outÑow rateThe driving source is located near the center of the molecular cloud, and the mass M _ Z300 M _ of the disk plus circumstellar envelope traced by millimeter continuum emission is D50 The M _ . outÑow appears to be bounded on most sides by higher density gas traced by C18O emission. Shocks identiÐed by and [S II] emission knots follow a NW-SE jet close to the young stellar object and then H 2 rotate more north-south along the edges of the CO Ñow. The most likely interpretation appears to be that the knots trace the working surfaces of a collimated jet that precesses through an angle of D45¡. Possible mechanisms that could produce the jet precession include tidal interactions between the disk and a companion star in a noncoplanar orbit or an anisotropic accretion event that dramatically altered the angular momentum vector of the disk.

Abstract. We present 7 mm observations of the dusty disk surrounding the 10 Myr old 1.5 M pre-main-sequence star CQ Tauri obtained at the Very Large Array with 0.8 arcsec resolution and 0.1 mJy rms sensitivity. These observations resolve the 7 mm emission in approximately the north-south direction, confirming previous results obtained with lower resolution. We use a twolayer flared disk model to interpret the observed fluxes from 7 mm to 1.3 mm together with the resolved 7 mm structure. We find that the disk radius is constrained to the range 100 to 300 AU, depending on the steepness of the disk surface density distribution. The power law index of the dust opacity coefficient, β, is constrained to be 0.5 to 0.7. Since the models indicate that the disk is optically thin at millimeter wavelengths for radii greater than 8 AU, the contribution of an optically thick region to the emission is less than 10%. This implies that high optical depth or complex disk geometry cannot be the cause of the observed shallow millimeter spectral index. Instead, the new analysis supports the earlier suggestion that dust particles in the disk have grown to sizes as large as a few centimeters. The dust in the CQ Tauri system appears to be evolved much like that in the TW Hydra system, a well-studied pre-main-sequence star of similar age and lower mass. The survival of gas-rich disks with incomplete grain evolution at such old ages deserves further investigations.