importvla – Import VLA archive file(s) to a measurement set – import/export task

Description

Imports an arbitrary number of VLA archive-format data sets into a casa measurement set. If more than one band is present, they will be put in the same measurement set but in a separate spectral window. The task will handle old style and new style VLA (after July 2007) archive data and apply the tsys to the data and to the weights.

Parameters

Title

Parameter	Default	Description
archivefiles	numpy.array( [  ] )	Name of input VLA archive file(s)
vis	''	Name of output visibility file
bandname	''	VLA frequency band name:''=>obtain all bands in the archive file
frequencytol	'150000.0Hz'	Frequency shift to define a unique spectra window (Hz)
project	''	Project name: '' => all projects in files
starttime	''	Start time to search for data
stoptime	''	End time to search for data
applytsys	True	Apply nominal sensitivity scaling to data and weights
autocorr	False	Import autocorrelations to MS, if set to True
antnamescheme	'new'	'old' or 'new'; 'VA04' or '04' for VLA ant 4
keepblanks	False	Fill scans with blank (empty) source names (e.g. tipping scans)
evlabands	False	Use updated eVLA frequencies and bandwidths for bands and wavelengths

Parameter Explanations

archivefiles

numpy.array( [  ] )

Name of input VLA archive file(s)

Default: none. Must be supplied

Examples: archivefiles = ‘AP314_A959519.xp1’ archivefiles=[‘AP314_A950519.xp1’, ‘AP314_A950519.xp2’]

vis

''

Name of output visibility file

Default: none. Must be supplied

Example: vis=’NGC7538.ms’

NOTE: Will not over-write existing ms of same name. A backup flag-file version ‘Original’ will be made in vis.flagversions. See help flagmanager.

bandname

''

VLA frequency band name:

Default: ‘’ (obtain all bands in the archive file) Options: ‘4’=48-96 MHz,’P’=298-345 MHz,’L’=1.15-1.75 GHz, ‘C’=4.2-5.1 GHz,’X’=6.8-9.6 GHz,’U’=13.5-16.3 GHz, ‘K’=20.8-25.8 GHz,’Q’=38-51 GHz

Example: bandname=’K’

frequencytol

'150000.0Hz'

Tolerance in frequency shift in making spectral windows

Default: = 150000.0Hz’

Example: frequencytol = 1500000.0 (units = Hz)

For Doppler shifted data, less than 10000 Hz may may produce too many unnecessary spectral windows.

project

''

Project name to import from archive files

Default: ‘’ (all projects in file)

Example: project=’AL519’ Project = ‘al519’ or AL519 will work.

WARNING: Do not include leading zeros; project = ‘AL0519’ will not work.

starttime

''

Time after which data will be considered for importing

Default: ‘’ (all)

syntax: starttime = ‘2003/1/31/05:05:23’. Date must be included!

stoptime

''

Time before which data will be considered for importing

Default: ‘’ (all)

syntax: starttime = ‘2003/1/31/08:05:23’. Date must be included!

applytsys

True

Apply data scaling and weight scaling by nominal sensitivity (~Tsys)

Default: True (strongly recommended) Options: True|False

autocorr

False

Import autocorrelations to MS

Default: False (no autocorrelations) Options: False|True

antnamescheme

'new'

‘old’ or ‘new’ antenna names.

Default: ‘new’ Options: new|old

• ‘new’ gives antnenna names ‘VA04’ or ‘EA13 for VLA telescopse 04 and 13 (EVLA)

• ‘old’ gives names ‘04’ or ‘13’

keepblanks

False

Should sources with blank names be filled into the data base?

Default: False (do not fill) Options: False|True

These scans are tipping scans (as of June 1, 2009) and should not be filled in the visibility data set.

evlabands

False

Use the EVLA’s center frequency and bandwidths for frequencies specified via wavelength or band.

Default: False Options: False|True