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ms.contsub - Function

1.3.1 Subtract the continuum from the visibilities


Description

NOT FULLY IMPLEMENTED YET. uvcontsub uses the cb tool for now. (The only reason to implement it in ms is to save time and disk space.)

This function estimates the continuum emission of the MS and writes a MS with that estimate subtracted, using the ms tool. The estimate is made, separately for the real and imaginary parts of each baseline, by fitting a low order polynomial to the unflagged visibilities selected by fitspw (depending on combine).

Arguments





Inputs

outputms

The name of the resulting measurement set

allowed:

string

Default:

fitspw

Line-free spectral windows (and :channels) to fit to

allowed:

variant

Default:

*

fitorder

The order of the polynomial to use when fitting.

allowed:

int

Default:

1

combine

Ignore changes in these columns (spw, scan, and/or state) when fitting.

allowed:

string

Default:

spw

Spectral windows (and :channels) to select

allowed:

variant

Default:

*

unionspw

The union of fitspw and spw, i.e. how much needs to be read. ’*’ always works, but may be more than you need.

allowed:

variant

Default:

*

field

Fields to include, by names or 0-based ids. (” => all)

allowed:

variant

Default:

scan

Only use the scan numbers requested using the msselection syntax.

allowed:

variant

Default:

intent

Only use the requested scan intents.

allowed:

string

Default:

correlation

Limit data to specific correlations (LL, XX, LR, XY, etc.).

allowed:

string

Default:

obs

Only use the requested observation IDs.

allowed:

string

Default:

whichcol

’DATA’, ’MODEL_DATA’, ’CORRECTED_DATA’, and/or ’FLOAT_DATA’

allowed:

string

Default:

CORRECTED_DATA

Returns
bool

Example

 
 
  ms.open("multiwin.ms")  
  ms.contsub(’contsub.ms’, fitspw=’0:0~123;145~211,2:124~255’, fitorder=0,  
             field=[0], spw=’0,2’)  
 
  In this example the continuum estimates are made by seperately averaging  
  channels 0:0~123;145~211 and 2:124~255, and the separate estimates are  
  subtracted from spws 0 and 2.  The output only includes field 0 and spws 0  
  and 2 (now called 1).  
 
  ms.contsub(’contsub.ms’, fitspw=’0:0~123;145~211,2:124~255’, fitorder=0,  
             field=[0], combine=’spw’)  
  ms.close()  
 
  This time the estimate was made by simultaneously averaging channels  
  0:0~123;145~211 and 2:124~255, and the continuum is subtracted from all the  
  spws, including 1 (treated as a completely line-filled spw).  The output only  
  includes field 0.  
 

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