AIPS HELP file for UVADC in 31DEC24
As of Sat Apr 20 3:24:01 2024
UVADC: Task to correct and add CLEAN components to uv data.
INPUTS
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK Input UV file disk unit #
NMAPS 0.0 4096.0 No. maps to use for model.
CHANNEL -1.0 9999.0 Spectral channel (0=>all)
Use 0 for continuum
BIF 0.0 9999.0 First IF (0=>1)
EIF 0.0 9999.0 Highest IF (0=>BIF to last)
IN2NAME Cleaned map name (name)
IN2CLASS Cleaned map name (class)
IN2SEQ 0.0 9999.0 Cleaned map name (seq. #)
IN2DISK Cleaned map disk unit #
INVERS -1.0 46655.0 CC file version #.
OUTNAME Output UV file name (name)
OUTCLASS Output UV file name (class)
OUTSEQ -1.0 9999.0 Output UV file name (seq. #)
OUTDISK Output UV file disk unit #.
BCOMP First CLEAN comp to sub.
1 per field.
NCOMP Last CLEAN comp to sub.
to use (0 => all)
FLUX Lowest CC component used.
CPARM (1) >0 => max. correct for
bandwidth smearing
(2) bandwidth corr. factor
(3) frequency corr. factor
FACTOR Factor times CLEAN fluxes.
0->1.0 add
-1.0 subtract
SMODEL Source model, 1=flux,2=x,3=y
See HELP SMODEL for models.
BADDISK Disks to avoid for scratch
HELP SECTION
UVADC
Task: Fourier transforms a CLEAN point model and corrects for geometric
distortions and adds to a uv data set. This task is designed for
use to correct the effects of minor geometric distortions due to
curvature of the sky and optionally (1) bandwidth smearing, (2)
errors in the nominal bandwidth, and (3) errors in the nominal
center frequency. It is mostly of use for snapshots with the
VLA.
If a correction for bandwidth smearing is requested then the
correction factor for each component/visibility/frequency is
limited to the range (0.98, 1.0 + 0.01*CPARM(1)) If the computed
correction is outside of this range then 1.0 + 0.01*CPARM(1) is
used. Note: this correction cannot recover badly smeared images
and will amplify the noise on some baselines!
If a correction is to be made to the nominal bandwidth to be
used for the bandwidth smearing correction this can be passed as
CPARM(2). A similar correction to the nominal center frequency
(and thus the u, v and w) can be passed as CPARM(3).
Model images made with both values of IMAGR's DO3DIMAG
option are handled correctly, as are multi-scale images. Set
NMAPS = NFIELD * NGAUSS.
NOTE: this task does NOT apply flagging or calibration tables
to the input UV data. Run SPLIT first if that operation is
desired.
Adverbs:
INNAME.....Input UV file name (name). Standard defaults.
INCLASS....Input UV file name (class). Standard defaults.
INSEQ......Input UV file name (seq. #). 0 => highest.
INDISK.....Disk drive # of input UV file.0 => any.
NMAPS......Number of image files to use for model. For multi-scale
models, set NMAPS = NFIELD * NGAUSS to include the Clean
components of the extended resolutions. If more than one
file is to be used, the NAME, CLASS, DISK and SEQ of the
subsequent image files will be the same as the first file
except that the LAST 3 or 4 characters of the CLASS will
be an increasing sequence above that in IN2CLASS. Thus,
if INCLASS='ICL005', classes 'ICL005' through 'ICLnnn'
or 'ICnnnn', where nnn = 5 + NMAPS - 1 will be used. Old
names (in which the 4'th character is not a number) are
also supported: the last two characters are '01' through
'E7' for fields 2 through 512. In old names, the highest
field number allowed is 512; in new names it is 4096.
CHANNEL....Frequency channel, 0 => all (use 0 for continuum)
BIF........First IF to process. 0=>1
EIF........Highest IF to process 0=> do BIF to highest.
Note: not all data sets will have IFs.
IN2NAME....Model map name (name). Standard defaults.
IN2CLASS...Model map name (class). Standard defaults.
IN2SEQ.....Model map name (seq. #). 0 => highest.
IN2DISK....Disk drive # of model map. 0 => any.
INVER......CC file ver. number. 0 => highest.
OUTNAME....Output UV file name (name). Standard defaults.
OUTCLASS...Output UV file name (class). Standard defaults.
OUTSEQ.....Output UV file name (seq. #). 0 => highest unique.
OUTDISK....Disk drive # of output UV file. 0 => highest with space
BCOMP......The first clean component to process. One value is
specified for each field used.
NCOMP......Number of Clean components to use for the model, one
value per field. If all values are zero, then all
components in all fields are used. If any value is not
zero, then abs(NCOMP(i)) (or fewer depending on FLUX and
negativity) components are used for field i, even if
NCOMP(i) is zero. If any of the NCOMP is less than 0,
then components are only used in each field i up to
abs(NCOMP(i)), FLUX, or the first negative whichever
comes first. If abs(NCOMP(i)) is greater than the number
of components in field i, the actual number is used. For
example
NCOMP = -1,0
says to use one component from field one unless it is
negative or < FLUX and no components from any other
field. This would usually not be desirable.
NCOMP = -1000000
says to use all components from each field up to the
first negative in that field.
NCOMP = -200 100 23 0 300 5
says to use no more than 200 components from field 1, 100
from field 2, 23 from field 3, 300 from field 5, 5 from
field 6 and none from any other field. Fewer are used if
a negative is encountered or the components go below
FLUX.
FLUX.......Only components > FLUX in absolute value are used in the
model.
CPARM......Task enrichment parameters:
(1) If CPARM(1) is > 0 then a correction is applied for the
effects of bandwidth smearing. The value of CPARM(1)
gives the maximum correction in percent.
(2) If CPARM(2) > 0 then CPARM(2) is a factor to be
multiplied times the nominal (header) value of the
bandwidth before making the bandwidth smearing
correction.
(3) If CPARM(3) > 0 then CPARM(3) is a factor to correct
the reference frequency. This will correct both the
reference frequency and the values of, u, v and w in the
output dataset.
FACTOR.....This value will be multiplied times the CLEAN component
flux densities before addition. The default 0->1.0, so the
clean component model will be added from the UV data.
FACTOR=-1 will subtract the clean component model from the
uv data.
SMODEL.....A single component model to be used instead of a CLEAN
components model; if abs (SMODEL) > 0 then use of this
model is requested.
SMODEL(1) = flux density (Jy)
SMODEL(2) = X offset in sky (arcsec)
SMODEL(3) = Y offset in sky (arcsec)
SMODEL(4) = Model type (uses point only)
BADDISK....The disk numbers to avoid for scratch files.
EXPLAIN SECTION