sdaverage – ASAP SD task: averaging and smoothing of spectra – single dish task

Description

Task sdaverage performs averaging in time/polarization and smoothing of the single-dish spectra. When timeaverage=True, spectra are averaged in time. Spectra within each scan ID are averaged when scanaverage=True. When polaverage=True, spectra are averaged in polarization and time (Note time averaging with polaverage=True would be discarded in future). See examples in below for details of time/polarization average. When kernel is specified (!=''), each spectrum is smoothed by convolving the kernel after averaging of spectra.

If you give multiple IFs (spectral windows) in spw, then your scantable will have multiple IFs by default. Averaging of multi-resolution (multi-IFs) spectra can be achieved by setting a sub-parameter in timeaverage, averageall = True. It handles multi-IFs by merging IFs which have overlaps in frequency coverages and assigning new IFs in the output spectra.

Set plotlevel >= 1 to plot spectrum before and after smoothing, and verify=True to interactively select whether or not accept smoothing results. NOTE, so far, there is no mechanism to verify averaging of spectra in time and/or polarization.

Parameters

Title
Parameter	Default	Description
infile	`''`
antenna	`int(0)`
field	`''`
spw	`''`
scan	`''`
pol	`''`
timeaverage	`False`
tweight	`'tintsys'`	weighting for time averaging ['tintsys', 'tsys', 'tint', 'var', or 'median']
scanaverage	`False`
averageall	`False`
polaverage	`False`
pweight	`'tsys'`	weighting for polarization averaging ['tsys' or 'var']
kernel	`''`	type of spectral smoothing kernel ['hanning', 'gaussian', 'boxcar', 'regrid'] (''=no smoothing)
kwidth	`int(5)`
chanwidth	`'5'`
verify	`False`
plotlevel	`int(0)`
outfile	`''`
outform	`'ASAP'`	output file format ['ASAP', 'MS2', 'ASCII', or 'SDFITS']
overwrite	`False`	overwrite the output file if already exists [True, False]

Parameter Explanations

infile

''

name of input SD dataset

antenna

int(0)

select an antenna name or ID, e.g. 'PM03' (only effective for MS input)

field

''

select data by field IDs and names, e.g. '3C2*' (''=all)

spw

''

select data by IF IDs (spectral windows), e.g. '3,5,7' (''=all)

scan

''

select data by scan numbers, e.g. '21~23' (''=all)

pol

''

select data by polarization IDs, e.g. '0,1' (''=all)

timeaverage

False

average spectra over time [True, False] (see examples in help)

tweight

'tintsys'

weighting for time averaging

scanaverage

False

average spectra within a scan number [True, False] (see examples in help)

averageall

False

set True only when averaging spectra with different spectral resolutions

polaverage

False

average spectra over polarizations [True, False]

pweight

'tsys'

weighting for polarization averaging

kernel

''

type of spectral smoothing kernel (''=no smoothing)

kwidth

int(5)

width of smoothing kernel in channels

chanwidth

'5'

width of regridded channels

verify

False

interactively verify the results of smoothing for each spectrum. [not available for kernel=”regrid”]

plotlevel

int(0)

plot and summarize results (0=none). See description in help

outfile

''

name of output file (See a WARNING in help)

outform

'ASAP'

output file format (See a WARNING in help)

overwrite

False

overwrite the output file if already exists