next up previous
Next: List of contributing authors Up: weeds Previous: Modeling a spectrum

For more information

This documentation manual covers the basic usage of the Weeds extension. More detailed information on each command is available using the Gildas online help, e.g.:

LAS90> help modsource
WEEDS\MODSOURCE = "python weeds/"
    Model  the  emission  of a source at the local thermodynamic equilibrium
    (LTE). The model paramaters (column density, kinetic temperature, source
    size,  line  width  and  velocity offset for each species) are read from
    MODFILE. The modeled antenna temperature is stored in the TB_MODEL memo-
    ry. For convenience the current spectra is also stored in a memory, OBS,
    so one can easily overplot the result of the model on the observed spec-
      MODFILE     the  name  of the file containing the parameters. The file
                  must have one line per species with at least  six  columns
                  containing respectively:
                  1) The species name
                  2) The column density for this species in cm-2
                  3) The exitation temperature in K
                  4) The source size in arcsecs
                  5) The offset velocity from the source VLSR, in km/s
                  6) The line FWHM in km/s
                  One  additional  column  may be used to select a different
                  database for each species:
                  7) The name of the database to use for  this  species.  If
                  empty,  the  default  database  (selected  with USE IN) is
                  The following options may be used at the end of the line:
                  /ABSORPTION  If this option is set, the component  is  as-
                  sumed  to  be  a foreground layer. See Belloche et al. A&A
                  559, A47 (2013) for details.
                  /PARTFUNC Q  Set the log10 of the  partition  function  at
                  the excitation temperature to Q. If not set, the partition
                  function values (log-log interpolated/extrapolated at  the
                  excitation  temperature)  from  the  selected database are
                  Lines that start with a "!" are treated as comments.
      ANTSIZE     the antenna size in meters
      /BACKGROUND set the background temperature to TBG, in  K.  Default  is
      /OPACITY  I store  the  opacity  of the Ith component in the TAU_MODEL
                  memory. Components are numbered in the same  order  as  in
                  MODFILE, starting from 1.
      /VERBOSE    prints  partition function, lines frequencies, upper level
                  energies and degeneracies, Einstein coefficients and opac-
                  ity at the line center.

For a more detailed description of the Weeds extension, we refer the interested reader to Maret, Hily-Blant, Pety et al., Astronomy & Astrophysics 526, A47 (2011). This paper describes the implementation of the extension, and gives more details about the spectroscopic databases that it uses, and explains how spectra are modeled7,

Weeds developers can be contacted by email at Bug reports should also be sent to this address.

next up previous
Next: List of contributing authors Up: weeds Previous: Modeling a spectrum
Gildas manager 2014-07-01