Title Chemical survey of hot cores and inner warm envelopes around YSOs Pi E. van Dishoeck Time 650 hrs 1. Name: Chemical survey of hot cores and inner warm envelopes around YSOs Authors: E. van Dishoeck, M. Wright, P. Schilke, F. Schoeier, ..... 2. Science goal: In recent years, it has become clear that the chemistry in the inner few hundred AU around deeply embedded (`class 0') YSOs is distinctly different from that of their outer colder envelopes. This chemistry is driven by sublimation of ices at temperatures around 90 K and subsequent high temperature chemical reactions between the evaporated species leading to complex organic species. These so-called `hot cores' have been detected both around low- and high-mass YSOs on the basis of single-dish unresolved data and their sizes have been determined from detailed modeling of continuum and multi-line data to be a few hundred AU (high-mass) (e.g., Wyrowski et al. 1999, ApJ 514, L43; van der Tak et al. 2000, ApJ 537, 283) to <100 AU (low-mass) (e.g. Ceccarelli et al. 2000, A&A 357, L9, Schoeier et al. 2002, A&A 390, 1001). ALMA can resolve these hot core regions and map the distribution of the molecules. These data can be used to test models of thermal evaporation vs. liberation of icy mantles in shocks, models of hot core chemistry (e.g., spatial separation of oxygen- and nitrogen-bearing species) and dynamical effects (are these complex molecules infalling or outflowing?). Chemical signatures of disks in the embedded stage can also be investigated. Multiline/multiband observations are needed to separate excitation effects from abundance effects. The source list should be coordinated with that of HIFI so that complementary information on H2O is also obtained. Band 5 will cover the H218O 204 GHz line, Band 8 the HDO 464 GHz line. Water is a crucial species in the chemistry. 3. Number of sources: 50 (20 high mass; 10 intermediate mass; 20 low-mass) 4. Coordinates: 4.1. 7 sources in Oph (RA=16:30, DEC=-24) 7 sources in Perseus (RA=03, DEC=+30) 7 sources in Taurus (RA=04, DEC=+20) 7 sources in Orion/Monoceros (RA=05-06, DEC=-05) 22 sources distributed over sky (RA=any, DEC=<+20) 4.2. Moving target: no 4.3. Time critical: no 4.4. Scheduling constraints: no 5. Spatial scales: 5.1. Angular resolution: 0.20"-0.25" 5.2. Range of spatial scales/FOV: 3"x3" 5.3. Required pointing accuracy: <1" (cf. specifications) 6. Observational setup 6.1. Single dish total power data: required Observing modes for single dish total power: nutator switch 6.2. Stand-alone ACA: beneficial/required (would be required if same data are also used to study outer envelope) 6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas: no 6.4. Subarrays of 12m baseline-ALMA antennas: no 7. Frequencies: 7.1. Receiver band: Band 3 Band 4 Band 5 Band 6 Band 7 Band 8 Band 9 7.2. Line: 1 1 1 3 4 1 2 settings 7.3. Spectral resolution (km/s): ~0.25 km/s (may be binned for weaker/broad lines) 7.4. Spectral coverage (km/s or GHz): maximum at spectral resolution with both polarizations (1 GHz Band 6-7; 2 GHz Band 9) 8. Continuum flux density: Band 3 Band 6 Band 7 Band 9 8.1. Typical value: 0.02-0.2 0.2-2 0.3-8 1-60 Jy low-mass 0.2-2 2-20 6-100 30-600 Jy high-mass 8.2. Continuum peak value: 0.2-2 2-20 8-100 60-600 (interpolate for Bands 3, 4, 5 and 8) 8.3. Required continuum rms: 0.1 Jy (not relevant for this program) 8.4. Dynamic range in image: >100 9. Line intensity: 9.1. Typical value: 2-150 K (low-mass) 3-500 K (high-mass) 9.2. Required rms per channel: 1 K 9.3. Spectral dynamic range: 3 (for species which are barely detected) >100 (for brightest lines) 9.4. Calibration requirements: absolute 10% repeatability 5% relative 5% See earlier response for motivation 10. Polarization: no 10.1. Required Stokes parameters: N/A 10.2. Total polarized flux density (Jy): N/A 10.3. Required polarization rms and/or dynamic range: N/A 10.4. Polarization fidelity: N/A 10.5. Required calibration accuracy: N/A 11. Integration time per setting: typically 1 hr per setting (for all bands, binning to lower spectral/spatial resolution for weakest lines) 12. Total integration time for program: 50 x 1 x 1 = 50 hr Band 3 50 x 1 x 1 = 50 hr Band 4 50 x 1 x 1 = 50 hr Band 5 50 x 3 x 1 = 150 hr Band 6 50 x 4 x 1 = 200 hr Band 7 50 x 1 x 1 = 50 hr Band 8 50 x 2 x 1 = 100 hr Band 9 650 hr Total *********************************************************************** Review Lee Mundy: OK.