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Basic Information on uvsub
Purpose: Subtract point source models from visibilities
Categories: uv analysis
UVSUB reads a file containing point source models and subtracts
them from the visibilities. Each model applies either to a
single spectral channel, or to all channels (continuum mode).
The output file contains all of the input channels whether
modified or not.
The name of the input visibility data sets (no default).
Standard Linetype: 'channel' (default) and 'velocity' are
recognized. Do 'help line' for more information. uvsub assumes
that only a single spectral window is processed.
The name of a text file containing the models (no default).
Each row must contain four columns which depend on the line type
specified. For line = 'channel':
CHAN No. FLUX DENSITY X OFFSET Y OFFSET
A channel number of zero is recognized as applying to all
channels (i.e. continuum). Otherwise, it is an error for the
channel number to lie outside the range in the data.
The flux density is in Jy and the offsets, true angular
distances in radians, are measured from the phase centre in the
offset = point source location - phase centre
For line = 'velocity', the channel number is replaced by
VELOCITY FLUX DENSITY X OFFSET Y OFFSET
The velocity must be in km/s, radio definition, i.e.
v = c (f0 - f) / f0,
with the same rest standard as the data-set. The model
visibility will be subtracted from the channel closest to this
velocity. Note that a rest frequency (f0) must be set in the
input visibility dataset in order to convert between velocity
and channel number (i.e. frequency).
Lines beginning with "#" are ignored.
The name of the output visibility data set (no default).
Revision: 1.6, 2013/08/30 01:49:21 UTC
Generated by firstname.lastname@example.org on 21 Jun 2016