suncasa.suncasatasks.private.task_subvs
Attributes
Functions
|
Perform vector subtraction for visibilities |
Module Contents
- suncasa.suncasatasks.private.task_subvs.subvs(vis=None, outputvis=None, timerange='', spw='', mode='linear', subtime1='', subtime2='', smoothaxis='time', smoothtype='flat', smoothwidth='5', splitsel=True, reverse=False, overwrite=False)[source]
Perform vector subtraction for visibilities Keyword arguments: vis – Name of input visibility file (MS)
default: none; example: vis=’ngc5921.ms’
- outputvis – Name of output uv-subtracted visibility file (MS)
default: none; example: outputvis=’ngc5921_src.ms’
- timerange – Time range of performing the UV subtraction:
default=’’ means all times. examples: timerange = ‘YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’ timerange = ‘hh:mm:ss~hh:mm:ss’
- spw – Select spectral window/channel.
default = ‘’ all the spectral channels. Example: spw=’0:1~20’
- mode – operation mode
- default ‘linear’
mode = ‘linear’: use a linear fit for the background to be subtracted mode = ‘lowpass’: act as a lowpass filter—smooth the data using different
smooth types and window sizes. Can be performed along either time or frequency axis
- mode = ‘highpass’: act as a highpass filter—smooth the data first, and
subtract the smoothed data from the original. Can be performed along either time or frequency axis
- mode = ‘linear’ expandable parameters:
- subtime1 – Time range 1 of the background to be subtracted from the data
default=’’ means all times. format: timerange = ‘YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’ timerange = ‘hh:mm:ss~hh:mm:ss’
- subtime2 – Time range 2 of the backgroud to be subtracted from the data
default=’’ means all times. examples: timerange = ‘YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’ timerange = ‘hh:mm:ss~hh:mm:ss’
- mode = ‘lowpass’ or ‘highpass’ expandable parameters:
- smoothaxis – axis of smooth
Default: ‘time’ smoothaxis = ‘time’: smooth is along the time axis smoothaxis = ‘freq’: smooth is along the frequency axis
- smoothtype – type of the smooth depending on the convolving kernel
Default: ‘flat’ smoothtype = ‘flat’: convolving kernel is a flat rectangle,
equivalent to a boxcar moving smooth
smoothtype = ‘hanning’: Hanning smooth kernel. See numpy.hanning smoothtype = ‘hamming’: Hamming smooth kernel. See numpy.hamming smoothtype = ‘bartlett’: Bartlett smooth kernel. See numpy.bartlett smoothtype = ‘blackman’: Blackman smooth kernel. See numpy.blackman
- smoothwidth – width of the smooth kernel
Default: 5 Examples: smoothwidth=5, meaning the width is 5 pixels
- splitsel – True or False. default = False. If splitsel = False, then the entire input
measurement set is copied as the output measurement set (outputvis), with background subtracted at selected timerange and spectral channels. If splitsel = True,then only the selected timerange and spectral channels are copied into the output measurement set (outputvis).
- reverse – True or False. default = False. If reverse = False, then the times indicated
by subtime1 and/or subtime2 are treated as background and subtracted; If reverse = True, then reverse the sign of the background-subtracted data. The option can be used for mapping absorptive structure.
- overwrite – True or False. default = False. If overwrite = True and
outputvis already exists, the selected subtime and spw in the output measurment set will be replaced with background subtracted visibilities