ALCHEMI Metadata Listing


TIP Last Modified: JeffMangum - 23 February 2021

This listing is meant to provide ALCHEMI Collab members working on research projects a detailed summary of all ALCHEMI survey measurements (both projects 2017.1.00161.L and 2018.1.00162.S).

The ALCHEMI metadata listing (in csv format) has been extracted using astroquery as follows:
ipython
In [1]: from astroquery.alma import Alma
In [2]: from astropy.io import ascii
In [3]: from astropy.table import vstack
# NOTE: Use public_data=False in the following two queries to get both public and proprietary data
In [4]: alchemi_data = Alma.query(payload={'project_code':'2017.1.00161.L'},public_data=False)
In [5]: b5_data = Alma.query(payload={'project_code':'2018.1.00162.S'},public_data=False)
In [6]: alchemi_data_all = vstack([alchemi_data,b5_data])
In [7]: alchemi_data.colnames
In [8]: ascii.write(alchemi_data_all,'ALCHEMIListingAll.csv',format='csv',fast_writer=False,overwrite=True)

The column names in this csv file are:
In [7]: alchemi_data.colnames
Out[8]:
['obs_publisher_did',
 'obs_collection',
 'facility_name',
 'instrument_name',
 'obs_id',
 'dataproduct_type',
 'calib_level',
 'target_name',
 's_ra',
 's_dec',
 's_fov',
 's_region',
 's_resolution',
 't_min',
 't_max',
 't_exptime',
 't_resolution',
 'em_min',
 'em_max',
 'em_res_power',
 'pol_states',
 'o_ucd',
 'access_url',
 'access_format',
 'proposal_id',
 'data_rights',
 'gal_longitude',
 'gal_latitude',
 'band_list',
 'em_resolution',
 'bandwidth',
 'antenna_arrays',
 'is_mosaic',
 'obs_release_date',
 'spatial_resolution',
 'frequency_support',
 'frequency',
 'velocity_resolution',
 'obs_creator_name',
 'pub_title',
 'first_author',
 'authors',
 'pub_abstract',
 'publication_year',
 'proposal_abstract',
 'schedblock_name',
 'proposal_authors',
 'sensitivity_10kms',
 'cont_sensitivity_bandwidth',
 'pwv',
 'group_ous_uid',
 'member_ous_uid',
 'asdm_uid',
 'obs_title',
 'type',
 'scan_intent',
 'science_observation',
 'spatial_scale_max',
 'qa2_passed',
 'bib_reference',
 'science_keyword',
 'scientific_category',
 'lastModified']

...and the definitions of each of these columns is as follows...
In [9]: Alma.help_tap()
Table to query is "voa.ObsCore".
For example: "select top 1 * from ivoa.ObsCore"
The scheme of the table is as follows.

  Name                 Type            Unit       Description
------------------------------------------------------------------------------------------
  access_format        char(9)                    Content format of the data
  access_url           char(72*)                  URL to download the data
  antenna_arrays       char(660*)                 Blank-separated list of Pad:Antenna pairs, i.e., A109:DV09 J504:DV02 J505:DV05 for antennas DV09, DV02 and DV05 sitting on pads A109, J504, and J505, respectively.
  asdm_uid             char(32*)                  UID of the ASDM containing this Field.
  authors              char(4000*)                Full list of first author and all co-authors
  band_list            char(30*)                  Space delimited list of bands
  bandwidth            double          GHz        Total Bandwidth
  bib_reference        char(4000*)                Bibliography code
  calib_level          int                        calibration level (2 or 3). 2 if product_type = MOUS, 3 if product_type = GOUS
  cont_sensitivity_bandwidth double          mJy/beam   Estimated noise in the aggregated continuum bandwidth. Note this is an indication only, it does not include the effects of flagging or dynamic range limitations.
  data_rights          char(11)                   Access to data.
  dataproduct_type     char(5*)                   type of product
  em_max               double          m          stop spectral coordinate value
  em_min               double          m          start spectral coordinate value
  em_res_power         double                     typical spectral resolution
  em_resolution        double          m          Estimated frequency resolution from all the spectral windows, using median values of channel widths.
  facility_name        char(3)                    telescope name
  first_author         char(256*)                 The first author as provided by <a href="http://telbib.eso.org">telbib.eso.org</a>.
  frequency            double          GHz        Observed (tuned) reference frequency on the sky.
  frequency_support    char(4000*)     GHz        All frequency ranges used by the field
  gal_latitude         double          deg        Galactic latitude of the observation for RA/Dec. Estimated using PyEphem and RA/Dec.
  gal_longitude        double          deg        Galactic longitude of the observation for RA/Dec. Estimated using PyEphem and RA/Dec.
  group_ous_uid        char(64*)                  Group OUS ID
  instrument_name      char(4)                    instrument name
  is_mosaic            char(1)                    Flag to indicate if this ASDM represents a mosaic or not.
  lastModified         char(*)                    Time stamp of last modification of the metadata
  member_ous_uid       char(64*)                  Member OUS ID
  o_ucd                char(35)                   UCD describing the observable axis (pixel values)
  obs_collection       char(4)                    short name for the data collection
  obs_creator_name     char(256*)                 case-insensitive partial match over the full PI name. Wildcards can be used
  obs_id               char(64*)                  internal dataset identifier
  obs_publisher_did    char(33*)                  publisher dataset identifier
  obs_release_date     char(*)                    timestamp of date the data becomes publicly available
  obs_title            char(256*)                 Case-insensitive search over the project title
  pol_states           char(64*)                  polarization states present in the data
  proposal_abstract    char(4000*)                Text search on the proposal abstract. Only abstracts will be returned which contain the given text. The search is case-insensitive.
  proposal_authors     char(2000*)                Full name of CoIs .
  proposal_id          char(64*)                  Identifier of proposal to which NO observation belongs.
  pub_abstract         char(4000*)                Case insensitive text search through the abstract of the publication.
  pub_title            char(256*)                 Case insensitive search through the title of the publication.
  publication_year     int                        The year the publication did appear in the printed version of the refereed journal.
  pwv                  float           mm         Estimated precipitable water vapour from the XML_CALWVR_ENTITIES table.
  qa2_passed           char(1)                    Quality Assessment 2 status: does the Member / Group OUS fulfil the PI's requirements?
  s_dec                double          deg        DEC of central coordinates
  s_fov                double          deg        size of the region covered (~diameter of minimum bounding circle)
  s_ra                 double          deg        RA of central coordinates
  s_region             char(*)         deg        region bounded by observation
  s_resolution         double          deg        typical spatial resolution
  scan_intent          char(256*)                 Scan intent list for the observed field.
  schedblock_name      char(128*)                 Name of the Scheduling Block used as a template for executing the ASDM containing this Field.
  science_keyword      char(200*)                 None
  science_observation  char(1)                    Flag to indicate whether this is a science observation.
  scientific_category  char(200*)                 None
  sensitivity_10kms    double          mJy/beam   Estimated noise in an nominal 10km/s bandwidth. Note this is an indication only, it does not include the effects of flagging or Hanning smoothing, and a 10km/s bandwidth may not be achievable with the data as taken.
  spatial_resolution   double          arcsec     Average of the maximum and minimum spatial resolution values of all spectral windows
  spatial_scale_max    double          arcsec     Due to the fact that radio antennas can not be placed infinitely close, measurements do have a smallest separation which translates into a maximal angular distance beyond which features can not be resolved reliably any more. Adding observations with the ALMA Total Power array can add those missing largest scales.
  t_exptime            double          s          exposure time of observation
  t_max                double          d          end time of observation (MJD)
  t_min                double          d          start time of observation (MJD)
  t_resolution         double          s          typical temporal resolution
  target_name          char(256*)                 name of intended target
  type                 char(16*)                  Type flags.
  velocity_resolution  double          m/s        Estimated velocity resolution from all the spectral windows, from frequency resolution.

Note that the information for a specific target or calibrator source in this listing is rolled-up into a single entry when the SB associated with the requested measurements contained multiple sessions. For example, for the SB named "ngc253_a_04_7M", which had 8 sessions, the UID for only three of those sessions is included in the listing above. Each of these three listings includes the cummulative total of measurements for all sessions for a particular target or calibrator. As this rolled-up information is all that ALMA provides to the outside world through their web interface, this is all that astroquery has access to.
-- JeffMangum - 2021-02-10
Topic revision: r6 - 2021-02-24, JeffMangum
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