Use Case:  Basic data mining.

Goal: Demonstrate basic retrieving capabilities of ALMA meta-data informations from user-selected positions in space and eventually frequency/velocity.

Contact Author:   F. Viallefond

• ASA user, OT user

• Staff Astronomer, Interactive Observer, OT sub-system.

Priority: Critical

Performance:   << minute

Frequency:  minutes to hours

Preconditions: 

1. Database is running
2. User got authenticated

1. Select one target using one of the following methods:
   
   • Object name or position on the sky
   • Not mandatory, if the goal is to search for continuum data, set frequency range(s)
     Alternate Course 1: if the goal is to search for line data, line name(s) and, not mandatory, transition(s).
     Input strings must support the "*" character to ease specifications and to mean any line and or transition in case the string corresponds to that single character.
     Alternate Course 2: Without selected range of frequencies and line/transition specifications the search is performed considering all the continuum and line ALMA projects for that source.
   • Not mandatory, for the alternate course 1, set the systemic velocity at reference.
   • Not mandatory, for the alternate course 1, set the velocity width at zero level.
2. Set a lower cut-off for the primary beam attenuation, e.g. use a default value of 1/10.
3. The target is searched within these constraints.
4. If the search is successful return a summary of basic meta-data parameters:
   1. The object name, its position on the sky
   2. The actual frequency range(s) from the meta-data
   3. The selected line(s)/transition(s), if any, or all the lines and transitions from the meta-data for that object if the "*" character has been used.
      N.B.: The user-specified line may not correspond to the line specified, if any, for the observations. In this case, the search is considered as successful if that line fall into a frequency range observed by ALMA, provided the velocity of the object is known.
   4. If line(s) has been specified, the systemic velocity at reference. This systemic velocity could correspond to a velocity used for ALMA observations of a line different from the one specified specified by the user in the selection criteria of the basic course.
   5. Per line or frequency range the synthetized beam size,
   6. Per line or frequency range the spectral resolution
   7. Per line or frequency range the integration time and rms noise level achieved at the position requested and the dynamic range, the primary beam correction factor (assuming a a Gaussian primary beam) applied, the radial distance (arcsec) to the pointing center in case of pointed observations.
   8. Per line or frequency range the observation date.
   9. A mean to access any meta-data item in the descriptor of the associated project(s).
      
   Alternate Course: No meta-data found: indicate which item(s) in the selection is (are) causing the unsuccess in the search.

Postconditions:

1. Idle state for the search engine,
2. Mean to modify selection criteria for a new search.

Issues to be Determined or Resolved:   None

Notes:   This Use Case was created by F. Viallefond.