POL2STACK

Combine multiple Q, U and I images and create a vector catalogue from them

Description:

This script combines multiple Q, U and I images and creates a vector catalogue from them.

By default, the Q, U, I and PI catalogue values, together with the maps specified by parameters " QUI" and " PI" , are in units of Jy/beam (see parameter Jy).

Usage:

pol2stack inq inu ini cat pi [retain] [qui] [in] [msg_filter] [ilevel] [glevel] [logfile]

Parameters:

CAT = LITERAL (Read)
The output FITS vector catalogue.
DEBIAS = LOGICAL (Given)
TRUE if a correction for statistical bias is to be made to percentage polarization and polarized intensity. [FALSE]
GLEVEL = LITERAL (Read)
Controls the level of information to write to a text log file. Allowed values are as for " ILEVEL" . The log file to create is specified via parameter " LOGFILE. In adition, the glevel value can be changed by assigning a new integer value (one of starutil.NONE, starutil.CRITICAL, starutil.PROGRESS, starutil.ATASK or starutil.DEBUG) to the module variable starutil.glevel. [" ATASK" ]
ILEVEL = LITERAL (Read)
Controls the level of information displayed on the screen by the script. It can take any of the following values (note, these values are purposefully different to the SUN/104 values to avoid confusion in their effects):
  • " NONE" : No screen output is created

  • " CRITICAL" : Only critical messages are displayed such as warnings.

  • " PROGRESS" : Extra messages indicating script progress are also displayed.

  • " ATASK" : Extra messages are also displayed describing each atask invocation. Lines starting with " > > >" indicate the command name and parameter values, and subsequent lines hold the screen output generated by the command.

  • " DEBUG" : Extra messages are also displayed containing unspecified debugging information. In addition scatter plots showing how each Q and U image compares to the mean Q and U image are displayed at this ILEVEL.

In adition, the glevel value can be changed by assigning a new integer value (one of starutil.NONE, starutil.CRITICAL, starutil.PROGRESS, starutil.ATASK or starutil.DEBUG) to the module variable starutil.glevel. [" PROGRESS" ]

IN = Literal (Read)
A group of container files, each containing three 2D NDFs in components Q, U and I, as created using the QUI parameter of the pol2cat script. Parameters INQ, INU and INI are used if a null (!) value is supplied for IN. [!]
INI = Literal (Read)
A group of input I maps in units of pW. Only used if a null value is supplied for parameter IN.
INQ = Literal (Read)
A group of input Q maps in unts of pW. Only used if a null value is supplied for parameter IN.
INU = Literal (Read)
A group of input U maps in units of pW. Only used if a null value is supplied for parameter IN.
JY = _LOGICAL (Read)
If TRUE, the output catalogue, and the output Q, U, PI and I maps will be in units of Jy/beam. Otherwise they will be in units of pW (in this case, the I values will be scaled to take account of any difference in FCFs for POL-2 and non-POL-2 observations). [True]
LOGFILE = LITERAL (Read)
The name of the log file to create if GLEVEL is not NONE. The default is " <command >.log" , where <command > is the name of the executing script (minus any trailing " .py" suffix), and will be created in the current directory. Any file with the same name is over-written. The script can change the logfile if necessary by assign the new log file path to the module variable " starutil.logfile" . Any old log file will be closed befopre the new one is opened. []
MSG_FILTER = LITERAL (Read)
Controls the default level of information reported by Starlink atasks invoked within the executing script. This default can be over-ridden by including a value for the msg_filter parameter within the command string passed to the " invoke" function. The accepted values are the list defined in SUN/104 (" None" , " Quiet" , " Normal" , " Verbose" , etc). [" Normal" ]
PI = NDF (Read)
The output NDF in which to return the polarised intensity map. No polarised intensity map will be created if null (!) is supplied. If a value is supplied for parameter IREF, then PI defaults to null. Otherwise, the user is prompted for a value if none was supplied on the command line. []
QUI = NDF (Read)
If a value is supplied for QUI, the total Q, U and I images that go into the final polarisation vector catalogue will be saved to disk as a set of three 2D NDFs. The three NDFs are stored in a single container file, with path given by QUI. So for instance if QUI is set to " stokes.sdf" , the Q, U and I images can be accessed as " stokes.q" , " stokes.u" and " stokes.i" . [!]
RETAIN = _LOGICAL (Read)
Should the temporary directory containing the intermediate files created by this script be retained? If not, it will be deleted before the script exits. If retained, a message will be displayed at the end specifying the path to the directory. [FALSE]