JCMT Legacy Surveys, the JCMT Data Management System, and Science with Archival Data

1. CADC JCMT Legacy Surveys,the JCMT Data Management System, and Science with Archival Data (Sub)Millimetre Observing TechniquesRussell O. Redman

2. JCMT Legacy Surveys • Legacy Projects with HARP/ACSIS & SCUBA2 • Too big for PATT Proposals • Too valuable to omit • Too obvious to award to one small group • Seven projects authorized • Debris Disks Survey • Gould's Belt Survey • Spectral Scan Survey • Galactic Plane Survey • Local Universe Survey • Cosmology Survey • SCUBA-2 All Sky Survey (SASSy)

3. JCMT Legacy Surveys • Debris Disk Survey Many main-sequence stars are surrounded by dusty “debris” disks which are fed by colliding asteroids and comets orbiting the stars, and thus trace the extrasolar equivalents of the Kuiper and asteroid belts in the Solar System. This survey will use SCUBA-2 to search 500 nearby main-sequence stars for submm radiation from the dust. At submm wavelengths the stellar photospheric signal is irrelevant, and cold disks are more easily detected than at shorter IR wavelengths.

4. JCMT Legacy Surveys • Gould’s Belt Survey We will map with SCUBA-2 almost all star-forming regions within 0.5 kpc that are accessible by the JCMT. Most of these are associated with Gould’s Belt and include many well-known regions. Towards the regions surveyed by SCUBA-2, the survey will be sensitive to every Class 0 & I protostar and every L1544-like pre-stellar core within 0.5 kpc and will take the number of such known sources from tens to thousands. We will obtain HARP maps, in three CO isotopomers, of the thousand brightest sources in order to distinguish between protostellar and pre-stellar cores, determine outflow characteristics, and probe the kinematic and density properties of the sources in a uniform manner. We will also map the brightest hundred sources with the SCUBA-2 polarimeter, producing the first statistically significant set of polarization maps in the submillimetre.

5. JCMT Legacy Surveys • Spectral Scan Survey Stars form in the densest, coldest, most quiescent regions of molecular clouds. Molecules provide the only probes which can reveal the dynamics, physics, chemistry and evolution of these regions. The Spectral Legacy Survey (SLS) proposes to use the unique spectral imaging capabilities of HARP/ACSIS to study the molecular inventory and the physical structure of a sample of objects spanning different evolutionary stages and different physical environments in molecular clouds and to probe their evolution during the star formation process. It is proposed to obtain fully sampled single-footprint spectral scans complete from 325 GHz to 375 GHz of 3 low mass protostars, one outflow and 5 young high mass sources, plus scans over 16 GHz of the band towards one PDR and one prestellar core.

6. JCMT Legacy Surveys • Galactic Plane Survey This survey will map two thirds of the Galactic Plane in the submillimetre continuum with SCUBA-2. The survey will provide the means to answer key questions in massive star formation by examining all stages of the process and all the significant mechanisms operating on scales from dense cores to that of the whole Galaxy. The sample size and vast range of environments will place massive star formation research onto a firm statistical basis for the first time. This will allow the most exhaustive investigation into the physics that determines the upper IMF that can be undertaken in a spiral galaxy from our unique close-up vantage point.

7. JCMT Legacy Surveys • Local Universe Survey We propose a survey with the JCMT using SCUBA-2 and HARP of a sample of 331 nearby galaxies. With a large, well-selected sample, we will be able to search for variations in the physical processes in the ISM as a function of galaxy type, metallicity, star formation rate, mass, and environment. Specific science goals include: searching for evidence of cold dust and measuring its mass fraction in galaxies of different types; measuring the amount of warm, dense molecular gas associated with star formation using the CO J=3-2 line; etc. NGC 2903 (Stevens et al. 2005)

8. JCMT Legacy Surveys • Cosmology Survey The survey will obtain an image as deep as that obtained for the HDF, but over an area comparable to a sky-survey Schmidt plate. It will yield a sufficiently robust sample of sources with redshift information to allow the clustering strength of submm galaxies to be accurately measured, and the link between sub-mm galaxies and dark-matter halos to be established as a function of redshift. It will allow the detailed study of the high-redshift progenitors of the richest structures seen in the present-day universe. The proposed observations will provide enough information to calculate bolometric luminosities, which in turn will allow us to refine the ‘Lilly/Madau’ diagram, and establish the link between obscured and visible star formation over cosmic history.

9. JCMT Legacy Surveys • SCUBA-2 All Sky Survey • The aims of this survey of the sub-mm sky using the SCUBA-2 are: • to provide an unbiased volume-limited census of local star formation within 1 kpc; • to complete the census of massive Infrared Dark Clouds (IRDCs) within our Galaxy; • to carry out a census of star-formation at high galactic latitude & solve the distributed T-Tauri problem; • to identify extreme members of the population of sub-mm galaxies and constrain the number count models for bright objects; • to probe foregrounds relevant for Planck but at high angular resolution; • to leave a lasting legacy for ALMA by completely surveying the sky visible to both JCMT and ALMA. • The “All Sky” referred to is a declination band in the range (–30, +70) degrees, encompassing 18,000 square degrees.

10. JCMT Legacy Surveys • Survey membership is still open • Members must be from partner countries • (usually) • Be prepared to put in some work • Observing, data reduction, analysis… • Student thesis projects will be protected • Observations will start • HARP in 07A • SCUBA-2 in 07B (?) • Public pages at http://www.jach.hawaii.edu/JCMT/surveys/ • Wiki pages at http://wiki.jach.hawaii.edu/jssg_wiki-bin/wiki/SiteMap • username survey; password legacy • See wiki pages for membership • Survey coordinators • Data Archive Coordinators (DAC)

11. JCMT-Archive • Canadian Astronomy Data Centre • Maintains JCMT Archive • Raw data files • Reduced data • Various formats • Primarily to aid selection of raw data • UNTIL NOW!!!

12. JCMT-DMSData Management System CADC • HARP-B/ACSIS & SCUBA2 are mapping instruments • > 200 TB of raw data! • Limited storage at JCMT • Solution: data streams daily from JCMT -> CADC -> Users •  NEW  Proprietary data will be distributed to users through the CADC • Every raw data file comes flagged with a release date • PROPRIETARY before the release date • PUBLIC after the release date • CADC users (i.e. with accounts) will be gathered into groups • Each PATT project & legacy survey constitutes a group • Only group members have access to proprietary data • CADC users can be members of multiple groups (projects)

13. JCMT-DMS Access Control CADC • JAC set initial group administrators • Five levels of access • General public • Public data products & metadata • Public outreach • Public users • + public raw data • Requires CADC account • Group members • + proprietary data & metadata • Requires group membership • Group administrator • + add/remove group members • Assigned by JAC • OMP

14. JCMT-DMS Data Reduction • New CADC Services for Data Reduction • Reduction of raw data to basic data products • Processing into advanced data products • Acceptance of externally generated data products

15. JCMT-DMS Basic Data Products • Reduced data • SCUBA-2 • Stokes I images (jiggle & scan maps) • Separate images for 850 and 450 m • Stokes IQU (or QU ?) cubes with polarimeter • HARP / ACSIS • Spectral datacubes (jiggle and scan maps) • Separate datacubes for each sub-band • Spectra (single points, 2&3 receptor chopping, etc.) • Spectro-polarimetric hypercubes • Standard ORAC-DR data reduction • Sky subtraction • De-spiking • Calibration • Mosaicing • Etc… • Intended to be publication quality!

16. JCMT-DMS Product Groupings • Products produced for different kinds of grouping • Observation (chiefly for quality checking) • Night (if observed > 1 time during night) • Project (if observed on > 1 night) • Public (if observed in > 1 project) • Release date for products = latest release date of raw data • observation, night, and project products are initially proprietary • Public products generated after raw data becomes public • Multiple versions will be generated for project & public products

17. JCMT–DMSAdvanced Data Products • Supported Products • Source & Line Catalogs • Clump-finding in 2D and 3D • Spectral Index Maps (SCUBA2) • Polarization Catalogs • Advanced products defined by Legacy Survey requirements • Algorithms still under development • send advice & suggestions to your survey Data Archive Coordinator (DAC) • Probably run under ORAC-DR (but does not have to be) • Does NOT include • Visualization • Modeling • Analysis

18. JCMT-DMS External Products CADC • Raw data and basic products can also be processed externally • e.g. cross-correlate SCUBA2 clumps list with other CO maps • Improved/custom data reduction algorithms • (Custom reduction by user request at CADC???) • Check-in of externally generated advanced data products • Products need to be vetted for format, content and suitability • Compatibility and standards • Images and data cubes must have WCS meeting FITS I, II and III • Spitzer, MSX, etc. (GLON-CAR, GLAT-CAR) • JCMT-OT (JSky - J2000.0 only; may need conversion routine) • Check FITS files with fitsverify + + + • PLEASE - no public announcements until products have been checked into the CADC and are at least accessible to group members!

19. JCMT-DMS Versions • Versions are required for • Project products • Over-written regularly • Published results • Saved indefinitely • There is a journal-sponsored movement to store published data (not just papers) with permanent URLs • CADC wants to join this effort • CADC is willing to create permanent URLs to hold product descriptions (provenance)

20. Science with ArchivesProposal Preparation • Has the source already been observed? • Have similar sources been observed? • Brightness, integration times, observing modes… • Has the source been observed at other transitions • CO, HCO+, H2CO, … • Line or continuum • Has the source been observed at other observatories? • Simultaneous proposals to multiple telescopes often fail • Representative sources might already have been observed

21. Science with Archives Data Mining • Large data sets are rarely analyzed completely • One man’s meat is another man’s poison (and vice versa) • Time variability • Moving sources • Exotic objects? • Cross-correlation of datasets • Objects prominent at multiple wavelengths • Pulsars • Quasars • Star-forming regions • H II regions • Etc…

22. Science with ArchivesVirtual Observatory • Major, international effort to make available electronically every public astronomical observation • Many things to many people • STANDARDS!!!! • (Start with FITS and generalize to everything…) • Octet • Early example of VO tool • Finds associations amongst observations • Launch from http://test.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/cvo/

23. Science with Archives Octet • Associations found using multiple, simultaneous queries • Associations must overlap in RA, Dec • Queries built of several conditions • Usually only one position condition • Energy/wavelength/frequency condition, not instrument/observatory

24. Science with Archives Octet • Displays association list • List observations by query • Select observations for display in Aladin

25. Science with Archives Octet / Aladin • Image 21cm continuum • Contours • Red - 21cm continuum • Blue - 850 micron continuum • Items to note • DR15 • Dust belt (850 m) • IRDC (850 m) • Ring from LBV • Beware of coincidences!