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

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

• (Sub)Millimetre Observing TechniquesRussell O.
  Redman

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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)

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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.

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JCMT Legacy Surveys

• Goulds 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 Goulds
  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.

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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.

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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.

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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 J3-2
  line etc.

NGC 2903 (Stevens et al. 2005)
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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.

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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.

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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/su
  rveys/
• Wiki pages at http//wiki.jach.hawaii.edu/jssg_wik
  i-bin/wiki/SiteMap
• username survey password legacy
• See wiki pages for membership
• Survey coordinators
• Data Archive Coordinators (DAC)

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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!!!

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JCMT-DMSData Management System
CADC

• HARP-B/ACSIS SCUBA2 are mapping instruments
• gt 200 TB of raw data!
• Limited storage at JCMT
• Solution data streams daily from JCMT -gt CADC -gt
  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)

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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

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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

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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, 23 receptor chopping,
  etc.)
• Spectro-polarimetric hypercubes
• Standard ORAC-DR data reduction
• Sky subtraction
• De-spiking
• Calibration
• Mosaicing
• Etc
• Intended to be publication quality!

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JCMT-DMS Product Groupings

• Products produced for different kinds of grouping
• Observation (chiefly for quality checking)
• Night (if observed gt 1 time during night)
• Project (if observed on gt 1 night)
• Public (if observed in gt 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

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JCMTDMSAdvanced 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

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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!

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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)

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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

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Science with Archives Data Mining

• Large data sets are rarely analyzed completely
• One mans meat is another mans 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

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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/

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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

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Science with Archives Octet

• Displays association list
• List observations by query
• Select observations for display in Aladin

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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!