Title Ultradeep ALMA continuum survey Pi A. Blain Time 4120 hrs 1. Name of program and authors Ultradeep ALMA continuum survey Andrew Blain 2. One short paragraph with science goal(s) High-redshift dusty galaxies are known to be responsible for a reasonable fraction of the energy emitted by all galaxies over the history of the Universe. Only a large interferometer offers the opportunity to study more the brightest 10% of the population. In particular, ALMA has the capability to detect all other classes of distant galaxies detected at radio, optical and X-ray wavelengths to generate a unified picture of galaxy evolution. We propose: i) to cover the entire area of the GOODS-S field, to provide a link between different populations of galaxies selected at a range of wavelengths. ii) to probe deeper in the enclosed UDF region and in the separate HDFS field. iii) to make a small number of single images to the deepest possible level inside. Note that should not make blank field images shallower than about 0.15 mJy RMS, as these can be done using single-antenna telescopes, and interesting populations of optically-selected galaxies are known from stacking analyses to be detectable at this level. The number of detected sources, some with spectral line information will provide the first insight into the properties of sub-L* dusty galaxies at high redshifts, and to address their spatial and spectral relationships with the faintest galaxies detected at other wavelengths. The ultradeep fields could detect the very first dusty objects to form at any plausible redshifts up to 20, and certainly impose severe upper limits on the properties of the faintest, earliest metal-rich objects. 3. Number of sources (e.g., 1 deep field of 4'x4', 50 YSO's, 300 T Tauri stars with disks, ...; do NOT list individual sources or your "pet object", except in special cases like LMC, Cen A, HDFS) 1 deep field of 15'x10' (GOODS-S/UDF) 1 deeper sub-field of 3'x3' (UDF) 1 field of 2'x2' to the same depth as UDF (HDF-S) 1 field of 1.3' radius to the same depth as UDF (A370) 2 ultradeep+ single pointings: one in the UDF, and one in the most strongest magnified region of A370. 4. Coordinates: 4.1. Rough RA and DEC (e.g., 30 sources in Taurus, 30 in Oph, 20 in Cha, 30 in Lupus) Indicate if there is significant clustering in a particular RA/DEC range (e.g., if objects in one particular RA range take 90% of the time) 03h 32m; -27 (GOODS) 22h 33m; -60 (HDF-S) 02h 23m; -01 (A370) Other deep fields could be possible, but these are the prime sites for deep surveys in the South. Other RA ranges can be filled by sparser observations of clusters of galaxies (see other proposals), which give ALMA a powerful boost using their gravitational lensing magnification. Also, COSMOS field at 10hr, -02deg is a good place to put a deep observation. At least one Ultradeep+ fields should be in the UDF to maximize multiwaveband coverage. 4.2. Moving target: yes/no (e.g. comet, planet, ...) No 4.3. Time critical: yes/no (e.g. SN, GRB, ...) No 4.4. Scheduling constraints: (optional) None 5. Spatial scales: 5.1. Angular resolution (arcsec): Angular resolution (arcsec): At least 0.1" to resolve galaxies 5.2. Range of spatial scales/FOV (arcsec): (optional: indicate whether single-field, small mosaic, wide-field mosaic...) Moderate field mosaic to ensure smooth coverage; however, no targets are larger than a few arcsec. 5.3. Required pointing accuracy: (arcsec) 1", unless mosaic imposes greater requirement. 6. Observational setup 6.1. Single dish total power data: no/beneficial/required No Observing modes for single dish total power: (e.g., nutator switch; frequency switch; position switch; on-the-fly mapping; and combinations of the above) 6.2. Stand-alone ACA: no/beneficial/required No 6.3. Cross-correlation of 7m ACA and 12m baseline-ALMA antennas: no/beneficial/required Possibly for increased depth if not required for other work 6.4. Subarrays of 12m baseline-ALMA antennas: yes/no No 7. Frequencies: 7.1. Receiver band: Band 3, 4, 5, 6, 7, 8, or 9 6/7 7.2. Lines and Frequencies (GHz): (approximate; do _not_ go into detail of correlator set-up but indicate whether multi-line or single line; apply redshift correction yourself; for multi-line observations in a single band requiring different frequency settings, indicate e.g. "3 frequency settings in Band 7" without specifying each frequency (or give dummies: 340., 350., 360. GHz). For projects of high-z sources with a range of redshifts, specify, e.g., "6 frequency settings in Band 3". Apply redshift correction yourself.) Top of band 6/bottom of band 7 - 280 GHz. Tunings at similar frequencies for all imaging, as 280-GHz is expected to lead to the detection of sources at the highest rate. May be sensible to shift tuning over several adjacent 8GHz ranges for imaging within each field to maximize the chances of serendipitous emission line detection. The decision on this should wait for a more concrete understanding of the range of emission properties of faint dusty galaxies, both to confirm the best frequency to search at, and the most efficient depth. 7.3. Spectral resolution (km/s): 300 km/s for serendipitous line detection 7.4. Bandwidth or spectral coverage (km/s or GHz): 8 GHz 8. Continuum flux density: 8.1. Typical value (Jy): (take average value of set of objects) (optional: provide range of fluxes for set of objects) Typical optical galaxies at 0.1mJy or less. Deep survey, so unknown 8.2. Required continuum rms (Jy or K): GOODS-S 0.02 mJy UDF/HDF-S/A370 0.004 mJy Ultradeep+ <0.001 mJy 8.3. Dynamic range within image: (from 7.1 and 7.2, but also indicate whether, e.g., weak objects next to bright objects) No bright objects expected (brightest ~ 10mJy). 8.4. Calibration requirements: absolute ( 1-3% / 5% / 10% / n/a ) repeatability ( 1-3% / 5% / 10% / n/a ) relative ( 1-3% / 5% / 10% / n/a ) relative 10% 9. Line intensity: N/A 9.1. Typical value (K or Jy): (take average value of set of objects) (optional: provide range of values for set of objects) 9.2. Required rms per channel (K or Jy): 9.3. Spectral dynamic range: 9.4. Calibration requirements: absolute ( 1-3% / 5% / 10% / n/a ) repeatability ( 1-3% / 5% / 10% / n/a ) relative ( 1-3% / 5% / 10% / n/a ) 10. Polarization: yes/no (optional) N/A 10.1. Required Stokes parameters: 10.2. Total polarized flux density (Jy): 10.3. Required polarization rms and/or dynamic range: 10.4. Polarization fidelity: 10.5. Required calibration accuracy: 11. Integration time for each observing mode/receiver setting (hr): GOODS - 3800s per pointing, 1000 pointings = 1050 hours HDF-S - 96000s per pointing, 20 pointings = 530 hours A370 - 96000s per pointing, 20 pointings = 530 hours UDF - 96000s per pointing, 60 pointings = 1590 hours Ultradeep - a 0.001mJy RMS pointing takes 420 hours (single field assumed for total time calculation 12. Total integration time for program (hr): 4120 hours (long term can be used) 13. Comments on observing strategy : (optional) (e.g. line surveys, Target of Opportunity, Sun, ...): Should be an excellent first look at representative areas of sky using ALMA's deep imaging capability. Probably best to make a very deep subfield as early as possible to verify the system, produce headline science results, check the strategy by estimating the faint counts, and provide some objects at a wide range of fluxes for follow-up imaging at higher frequencies (in better weather?). The required atmospheric conditions will be determined by experience, but in principle, 280GHz observations could be done in the daytime and worse conditions, subject to the coherence being verfied to be acceptable under these conditions. Only ALMA can confirm the density of sources, but expect 20 sources per square arcmin at detection threshold of 0.1mJy and 80 per square arcmin at detection threshold of 0.02mJy: should get 3000 detections in GOODS-S field and 700 in UDF, matching reasonably well to the surface density of galaxies in the optical images. -------------------------------------------------- Review v2.0: 1.1.6 Sensitivity calculations were checked. In some of the proposed fields (close to the equator), we may have to check whether there are any nearby strong sources or not; if we go down to a microJy level; sidelobes from such a luminous (~ 10 - 100 mJy level) mm source could be problematic, although it is expected that the dynamic range will be high enough thanks to the huge number of antennas.