hanningsmooth – Hanning smooth frequency channel data to remove Gibbs ringing – manipulation task

Description

The hanningsmooth task uses the MSTransform framework underneath but keeps roughly the same interface as the old hanningsmooth task.

This function Hanning smooths the frequency channels with a weighted running average. The weights are 0.5 for the central channel and 0.25 for each of the two adjacent channels. The first and last channels are flagged. Inclusion of a flagged value in an average causes that data value to be flagged.

If the ‘CORRECTED’ data column is requested for an MS that does not contain this column, it will use ‘DATA’ to calculate the smoothing and save it to ‘DATA’ in the output MS.

WARNING: by default, all visibility columns will be smoothed.

Parameters

Title

Parameter	Default	Description
vis	''	Name of input visibility file
outputvis	''	Name of output visibility file
keepmms	True	Create a Multi-MS as the output if the input is a Multi-MS.
field	''	Select field using field id(s) or field name(s)
spw	''	Select spectral window/channels
scan	''	Scan number range
antenna	''	Select data based on antenna/baseline
correlation	''	Select data based on correlation
timerange	''	Select data based on time range
intent	''	Select observing intent
array	''	Select (sub)array(s) by array ID number.
uvrange	''	Select data by baseline length.
observation	''	Select by observation ID(s)
feed	''	Multi-feed numbers: Not yet implemented.
datacolumn	'all'	Which data column(s) to use for processing

Parameter Explanations

vis

''

Name of input visibility file

Default: none

Example: vis=’ngc5921.ms’

outputvis

''

Name of output visibility file

Default: ‘’ (same as vis)

Example: outputvis=’ngc5921_out.ms’

keepmms

True

Create a Multi-MS as the output if the input is a Multi-MS.

Default: True Options: True|False

By default it will create a Multi-MS when the input is a Multi-MS. The output Multi-MS will have the same partition axis of the input MMS. See CASA Docs for more information on the MMS format.

field

''

Select field using field id(s) or field name(s)

Default: ‘’ (all fields)

Use ‘go listobs’ to obtain the list id’s or names. If field string is a non-negative integer, it is assumed a field index, otherwise, it is assumed a field name.

Examples: field=’0~2’; field ids 0,1,2 field=’0,4,5~7’; field ids 0,4,5,6,7 field=’3C286,3C295’; field named 3C286 and 3C295 field = ‘3,4C*’; field id 3, all names starting with 4C

spw

''

Select spectral window/channels

Default: ‘’=all spectral windows and channels

Examples: spw=’0~2,4’; spectral windows 0,1,2,4 (all channels) spw=’<2’; spectral windows less than 2 (i.e. 0,1) spw=’0:5~61’; spw 0, channels 5 to 61 spw=’0,10,3:3~45’; spw 0,10 all channels, spw 3 - chans 3 to 45. spw=’0~2:2~6’; spw 0,1,2 with channels 2 through 6 in each. spw = ‘*:3~64’ channels 3 through 64 for all sp id’s spw = ‘ :3~64’ will NOT work.

NOTE: mstransform does not support multiple channel ranges per spectral window (‘;’).

scan

''

Scan number range

Subparameter of selectdata=True Default: ‘’ = all

antenna

''

Select data based on antenna/baseline

Subparameter of selectdata=True Default: ‘’ (all)

If antenna string is a non-negative integer, it is assumed an antenna index, otherwise, it is assumed as an antenna name

Examples: antenna=’5&6’; baseline between antenna index 5 and index 6. antenna=’VA05&VA06’; baseline between VLA antenna 5 and 6. antenna=’5&6;7&8’; baselines with indices 5-6 and 7-8 antenna=’5’; all baselines with antenna index 5 antenna=’05’; all baselines with antenna number 05 (VLA old name) antenna=’5,6,10’; all baselines with antennas 5,6,10 index numbers

antenna=’!ea03,ea12,ea17’: all baselines except those that include EVLA antennas ea03, ea12, or ea17.

correlation

''

Select data based on correlation

Default: ‘’ ==> all

Example: correlation=”XX,YY”.

timerange

''

Select data based on time range

Subparameter of selectdata=True Default = ‘’ (all)

Examples: timerange = ‘YYYY/MM/DD/hh:mm:ss~YYYY/MM/DD/hh:mm:ss’ (Note: if YYYY/MM/DD is missing date defaults to first day in data set.) timerange=’09:14:0~09:54:0’ picks 40 min on first day timerange= ‘25:00:00~27:30:00’ picks 1 hr to 3 hr 30min on NEXT day timerange=’09:44:00’ pick data within one integration of time timerange=’>10:24:00’ data after this time

intent

''

Select observing intent

Default: ‘’ (no selection by intent)

Example: intent=’BANDPASS’ (selects data labelled with BANDPASS intent)

array

''

(Sub)array number range

Default: ‘’ (all)

uvrange

''

Select data by baseline length.

Default = ‘’ (all)

Examples: uvrange=’0~1000klambda’; uvrange from 0-1000 kilo-lambda uvrange=’>4klambda’;uvranges greater than 4 kilo-lambda uvrange=’0~1000km’; uvrange in kilometers

observation

''

Select by observation ID(s)

Subparameter of selectdata=True Default: ‘’ = all

Example: observation=’0~2,4’

feed

''

Selection based on the feed

NOT IMPLEMENTED YET! Default: ‘’ = all

datacolumn

'all'

Which data column(s) to use for processing

(case-insensitive). Default: ‘all’ (= whichever of the options that are present) Options: ‘data’, ‘model’, ‘corrected’, ‘all’,’float_data’, ‘lag_data’, ‘float_data,data’, ‘lag_data,data’

Example: datacolumn=’data’