AIPS HELP file for MAPBM in 31DEC24
As of Wed Apr 24 22:41:46 2024
MAPBM: Map VLA beam polarization
INPUTS
INNAME Input UV data (name)
INCLASS Input UV data (class)
INSEQ Input UV data (seq. #)
INDISK Input UV data disk drive #
SOURCES Source (pointings) list
QUAL Source qualifier
TIMERANG Time range to process.
BIF 0.0 100.0 Lowest IF number 0=>all
EIF 0.0 100.0 Highest IF number 0=>all
PMODEL Source polarization
DOCALIB -1.0 101.0 > 0 calibrate data & weights
> 99 do NOT calibrate weights
GAINUSE CL table to apply
DOPOL -1.0 10.0 If >0.5 correct polarization.
PDVER PD table to apply (DOPOL>0)
BLVER BL table to apply.
FLAGVER Flag table version
DOBAND -1.0 10.0 If >0 apply bandpass cal.
Method used depends on value
of DOBAND (see HELP file).
BPVER Bandpass table version
SMOOTH Smoothing function. See
HELP SMOOTH for details.
OUTNAME Output image name (name)
OUTDISK Output image disk drive #
Note: OUTCLASS='ANT_#'
'RMS_#' for rms maps
where # is antenna number.
OUTSEQ -1.0 32000.0 Output seq. no.
IMSIZE 1. 4096. Image size (X,Y) in pixels
CELLSIZE 1.E-12 (X,Y) size of grid in asec
APARM Task enrichment parms
(1) Avg. time in sec.
(2) Blank time at the begin.
of the avg. time in sec.
(3) 0 => no rms maps
1 => yes rms maps
no scaling for the
rms maps
(4) 0 => Yes dividing of a
polarization map by
its maximum
1 => No dividing of a
polarization map by
its maximum
(5) 0 => create separate maps
for each of selected
antennas
1 => combine data of all
selected antennas
and create one map
ANTENNAS Selected antennas from the
list of measured antennas
0 => all
If any number is negative
then all antennas listed
are NOT selected and
all others are.
BASELINE The reference antenna list
Must be given!!!
BADDISK Disk drive #'s to avoid
HELP SECTION
MAPBM
Type: Task
Use: Image VLA quasi "holography" mode data to make total
intensity gain images and images of the fractional Q, U
and V polarizations. The uv data are expected to be
rasters in azimuth and elevation. Prior calibration and
editing may be applied and then the data is then averaged
over baseline.
The resultant images are the qubes of primary beam
(and the rms of each of these) for each of the selected antennas
with the stokes I, Q, U and V as the third axis.
For Stokes I, the image is the average observed I
divided by PMODEL(1). For the other values of Stokes the
image values are the real part of the ratio of the complex Stokes'
value to I (complex also) after correction for source polarization.
Note: QUACK is needed to eliminate the first couple of
integrations of a raster while the on-line system
(VLA 9/93) sorts out where it needs to be.
Note: QUACK may not be enough; exceedingly painful,
careful editing of the data will be needed to insure that
all the spurious points are removed.
Adverbs:
INNAME.....Input UV data file (name). Standard defaults.
MUST be a multi source file.
INCLASS....Input UV data file (class). Standard defaults.
INSEQ......Input UV data file (seq. #). 0 => highest.
INDISK.....Input UV data file disk drive #. 0 => any.
SOURCES....List of sources (pointings) to be processed.
All blank means any.
QUAL.......Source qualifier for rasters.
TIMERANG...Time range of the data to be processed. In order:
Start day, hour, min. sec,
end day, hour, min. sec. Days relative to ref.
date.
BIF........First IF to image. 0=>all.
EIF........Highest IF to image. 0=>all higher than BIF
PMODEL.....The Stokes parameters for the source.
PMODEL(1) = I flux density (Jy)
PMODEL(2) = Q flux density (Jy)
PMODEL(3) = U flux density (Jy)
PMODEL(4) = V flux density (Jy)
DOCALIB....If true (>0), calibrate the data using information in the
specified Cal (CL) table for multi-source or SN table for
single-source data. Also calibrate the weights unless
DOCALIB > 99 (use this for old non-physical weights).
GAINUSE....CL table version number to apply. 0=> highest.
DOPOL......If > 0.5 then correct data for instrumental polarization
as represented in the AN or PD table. This correction is
only useful if PCAL has been run or feed polarization
parameters have been otherwise obtained. See HELP DOPOL
for available correction modes: 1 is normal, 2 and 3 are
for VLBI. 1-3 use a PD table if available; 6, 7, 8 are
the same but use the AN (continuum solution) even if a PD
table is present.
PDVER......PD table to apply if PCAL was run with SPECTRAL true and
0 < DOPOL < 6. <= 0 => highest.
BLVER......Version number of the baseline based calibration (BL)
table to appply. <0 => apply no BL table, 0 => highest.
FLAGVER....Specifies the version of the flagging table to be
applied. 0 => highest numbered table. <0 => no flagging
to be applied.
DOBAND.....If true (>0) then correct the data for the shape of the
antenna bandpasses using the BP table specified by BPVER.
The correction has five modes:
(a) if DOBAND=1 all entries for an antenna in the table
are averaged together before correcting the data.
(b) if DOBAND=2 the entry nearest in time (including
solution weights) is used to correct the data.
(c) if DOBAND=3 the table entries are interpolated in
time (using solution weights) and the data are then
corrected.
(d) if DOBAND=4 the entry nearest in time (ignoring
solution weights) is used to correct the data.
(e) if DOBAND=5 the table entries are interpolated in
time (ignoring solution weights) and the data are then
corrected.
BPVER......Specifies the version of the BP table to be applied.
<0 => no bandpass correction done.
SMOOTH.....Specifies the type of spectral smoothing to be applied to
a uv database . The default is not to apply any smoothing.
The elements of SMOOTH are as follows:
SMOOTH(1) = type of smoothing to apply: 0 => no smoothing
To smooth before applying bandpass calibration
1 => Hanning, 2 => Gaussian, 3 => Boxcar, 4 => Sinc
To smooth after applying bandpass calibration
5 => Hanning, 6 => Gaussian, 7 => Boxcar, 8 => Sinc
SMOOTH(2) = the "diameter" of the function, i.e. width
between first nulls of Hanning triangle and sinc
function, FWHM of Gaussian, width of Boxcar. Defaults
(if < 0.1) are 4, 2, 2 and 3 channels for SMOOTH(1) =
1 - 4 and 5 - 8, resp.
SMOOTH(3) = the diameter over which the convolving
function has value - in channels. Defaults: 1,3,1,4
times SMOOTH(2) used when input SMOOTH(3) < net
SMOOTH(2).
OUTNAME....Output image name (name). Standard defaults.
OUTDISK....The disk drive # of output images. 0 => highest
with space.
Note: OUTCLASS='ANT_#' ('RMS_#' for rms maps)
where # is the antenna number.
In the case when all antenna data averaged (APARM(5) = 1)
OUTCLASS='ANT_*'
OUTSEQ.....Output sequence number. 0 => highest unique.
IMSIZE.....(X,Y) image size in pixels. Should be odd.
CELLSIZE...(X,Y) pixel separation in asec. It should be close to the
actual separation at the pointing at the holography
measurements.
APARM......Task enrichment parameters.
(1) Averaging time in seconds; normally interval
of each pointing.
(2) Time in seconds to ignore at the beginning of
each pointing; this allows for antenna move.
(3) 0 => no rms maps
1 => yes rms maps
no scaling (dividing by the map maxima)
for the rms maps
(4) 0 => Yes dividing of a polarization map by
its maximum
1 => No dividing of a polarization map by
its maximum
(5) 0 => create separate maps for each selected
antennas
1 => combine data of all selected antennas
and create one map
ANTENNAS...A list of the antennas to be selected.
0 => all.
If any number is negative then all antennas listed are NOT
selected and all others are.
ANTENNAS list is the list of measured antennas.
BASELINE...List of the reference antennas. Must be given!!!
BADDISK....Disk drive #'s to avoid for scratch files
EXPLAIN SECTION
You can create the average maps averaging all selected antennas
and all selected reference antennas, or
You can create maps for each selected antenna separately.
OUTCLASS of the output map is 'ANT_#'.
For 'rms' maps the OUTCLASS of the output map is 'RMS_#'.
where # is the antenna number.
In the case when all antenna data averaged (APARM(5) = 1)
OUTCLASS='ANT_*'
Each output map is the cube with the third axis dimension is 4
(one plate for Stokes parameter).
So KNTR can plot all polarization at one page. The four maps can
be normalized to 1(one) (APARM(4)) dividing by the maximum value
at each plate. No normalization for the 'rms' maps.
So the values of the maps have to be multiplied by the scale factors.
The value of the scale factors can be found as keywords using aips
verb 'imh'
The scaling all stokes maps to 1, simplifies selection of the levels
in KNTR.