1. Name: Survey of the central fields in massive molecular outflows with the ALMA interferometer. Authors: D. Shepherd et al. 2. Science Goal: Molecular outflows from massive and intermediate-mass young stars are generally complex and are the result of the combined energetics from several OB stars and lower mass YSOs in a relatively dense cluster. The global properties of massive flow complexes is important for understanding the star formation efficiency in massive star forming regions and being able to relate galactic and extra-galactic star formation regions. In a companion proposal, 20 molecular outflow sources are chosen to obtain lower resolution observations of the molecular outflows and dust emission near embedded stars in the central clusters. This proposal seeks to obtain high angular resolution molecular line and continuum observations on the central fields in the survey to map the outflowing gas back to specific sources and obtain a census of the number of sources in the cluster and the mass, distribution, and kinematics of circumstellar material. Source and circumstellar properties will then be compared to outflow properties to examine trends in circumstellar material versus outflow evolution. Thus, a sensitive survey of outflow and dense molecular gas from intermediate to high-mass YSOs in lines such as 12CO(J=2-1), 13CO(J=2-1), C18O(J=2-1), C17O(2-1), and hydrogen recombination lines (H28-30alpha) (along with several other shock and high-density tracers in bands 6 & 7 (mm to submm) using the ALMA and ACA combined arrays would provide a uniform sample with accurate, high resolution, estimates of high velocity gas near protostars, dense gas, and cluster properties. Continuum observations with at least 2GHz of bandwidth will also detect embedded high- and intermediate-mass stars in the cluster that may be contributing to the outflow dynamics. If the continuum emission can be distributed between 230 & 219 GHz will be used to estimate the millimeter SED of the driving source(s). The mosaics must also be sensitive to size scales up to about 60" in the outflow. Multi-scale reconstruction of the combined uv-data will be needed to generate the final mosaic images. High resolution is NOT required at this stage. Promising candidates will be identified during this program and high-resolution and high-sensitivity follow up studies will be proposed. ************** Note: A similar survey should be contemplated for lower mass outflows. The low-mass survey should be separate from this one because: 1) The lines chosen will likely be different (fewer high density tracers) and the spectral resolution will be different. 2) The spatial resolution should be lower (e.g. low-mass outflows are generally less than a kiloparsec away, lower resolution is required match the expected size scale of circumstellar emission around low-mass YSOs). 3) The continuum sensitivity will need to be higher to detect dust emission around the less luminous sources. ************** 3. Number of Sources: 20 4. Coordinates: 4.1 To be taken from a list. 4.2 Moving target: No 4.3 Time Critical: No 5. Spatial Scales: 5.1 Angular Resolution: 0.01" to 0.1" (depending on source) 5.2 Range of spatial scales required: 0.01" to 5" (depending on source) FOV = 30" 5.3 Single dish: No (we want to resolve out some of the confusing outflow emission) 5.4 ACA: Yes 5.5 Subarrays: No 6. Frequencies: 6.1 Receiver Bands: 6 & 7 6.2 Band 6 Lines: CO(J=2-1), 13CO(J=2-1), C18O(J=2-1) Frequencies (GHz): 230.538, 220.398, 219.560 Band 7 Lines: H30alpha, CH3CN(16-15), SiO(J=7-6) Frequencies (GHz): 231.901, 294.161, 303.927 (only a few representative lines listed here). 6.3 Spectral Resolution (km/s): 0.1 to 0.3 km/s (differs with line depending on whether it is an outflow or disk/dense gas tracer). 6.4 Spectral Coverage (km/s or GHz): 20-100 km/s per line 7. Continuum flux density: 7.1 Typical Value: 0.5-10 mJy 7.2 Continuum Peak Value: Varies with source. 7.3 Required Continuum RMS: 0.03 mJy (to detect primary driving source of the flow as well as any lower-mass YSOs in the cluster) 7.4 Dynamic Range in Image: > 20 8. Line Intensity: 8.1 Typical value: > 10 Jy at 12CO line peak 10-100 mJy in high velocity wings few mJy to microJy for RRLs. 8.2 Required RMS per channel: 1 mJy/beam 8.3 Spectral Dynamic Range: > 100 9. Polarization: No 10. Time requested: 10.1 Integration time per source for the ALMA array: 30" primary beam, single field For a typical source/line with 0.3 km/s resolution 1 mJy/beam RMS in each field => 1 hr integration x 20 sources = 20 hrs 10.2 ACA observations take about 4 times longer to achieve a similar RMS as the ALMA array. Thus, this project requires 4 hrs of ACA integration time x 20 sources = 80 hrs. 10.3 In summary, this project requires 20 hours of ALMA array time, and 80 hours of ACA time. (overhead is not included in this estimate). ***************************************************************** Review Munetake Momose: This is a companion plan to 2.2.7., but it seems to me that the description is quite confusing (maybe due to some editorial error...); I believe this plan originally intends to make single pointing observations with fairly high angular resolution (0.1-0.01") to reveal the central regions of clusters, but in the latter half of this proposal there is a description of mosaics or a statement that "High resolution in NOT important required at this stage ...", which seems to be "contamination" from the DRSP 2.2.7. This may be an editorial error, but I recommend that both 2.2.7 - 2.2.8 should be re-considered to fit them into the current baseline ALMA project. Comment Ewine: Put ALMA time to 20 hr. Reconsider DRSP when situation on ACA and its sensitivity are clarified.