An experimental clone of uvcontsub
uvcontsub3 is an experimental clone of uvcontsub with the goal of taking
less time and temporary disk space.
Continuum fitting and subtraction in the uv plane:
This task estimates the continuum emission by fitting polynomials to
the real and imaginary parts of the spectral windows and channels
selected by fitspw. This fit represents a model of the continuum in
all channels.
The fitted continuum spectrum is subtracted from all channels
selected in spw, and the result (presumably only line emission)
is stored in a new MS (vis + ".contsub").
It will read from the CORRECTED_DATA column of vis if it is present,
or DATA if it is not. Whichever column is read is presumed to have
already been calibrated.
Keyword arguments:
vis -- Name of input visibility file
default: none; example: vis='ngc5921.ms'
fitspw -- Selection of spectral windows and channels to use in the
fit for the continuum, using general spw:chan syntax.
See the note under combine.
default: '' (all)
example: fitspw='0:5~30;40~55'
combine -- Let the continuum estimation span multiple spectral windows.
default = '' (Make separate estimates for each spw.)
combine = 'spw': Necessary when one or more of the spws are
completely blanketed by lines, so the estimate
must be made in different spws.
fitorder -- Polynomial order for the fits of the continuum w.r.t.
frequency. fitorders > 1 are strongly discouraged
because high order polynomials have more flexibility, may
absorb line emission, and tend go wild at the edges of
fitspw, which is not what you want.
default: 0 (constant); example: fitorder=1
field -- Field selection for continuum estimation and subtraction.
The estimation and subtraction is done for each selected field
in turn. (Run listobs to get lists of the ID and names.)
default: ''=all fields. If the field string is a non-negative
integer, it is assumed to be a field index
otherwise, it is assumed to be a field name
field='0~2'; field ids 0,1,2
field='0,4,5~7'; field ids 0,4,5,6,7
field='3C286,3C295'; fields named 3C286 and 3C295
field = '3,4C*'; field id 3, all names starting with 4C
spw -- Select spectral windows for the output.
default: ''=all spectral windows
N.B. uvcontsub3 does not yet support exclusion by channels for
the output. Meanwhile, use split to further reduce the size
of the output MS if desired.
spw='0~2,4'; spectral windows 0,1,2,4
spw='<2'; spectral windows less than 2 (i.e. 0,1)
scan -- Scan number range
default: ''=all
intent -- Select by scan intent (state). Case sensitive.
default: '' = all
Examples:
intent = 'CALIBRATE_ATMOSPHERE_REFERENCE'
intent = 'calibrate_atmosphere_reference'.upper() # same as above
# Select states that include one or both of CALIBRATE_WVR.REFERENCE
# or OBSERVE_TARGET_ON_SOURCE.
intent = 'CALIBRATE_WVR.REFERENCE, OBSERVE_TARGET_ON_SOURCE'
correlation -- Select correlations, e.g. 'rr, ll' or ['XY', 'YX'].
default '' (all).
observation -- Select by observation ID(s).
default: '' = all
1.8.0