AIPS HELP file for SOUSP in 31DEC24
As of Wed May 1 23:53:17 2024
SOUSP: Fits, plots, returns spectral index parameters
INPUTS
INNAME Input UV file name (name)
INCLASS Input UV file name (class)
INSEQ 0.0 9999.0 Input UV file name (seq. #)
INDISK 0.0 9.0 Input UV file disk unit #
SRCNAME Source name
CALCODE Calibrator code
QUAL -1.0 Source qualifier -1 => any
DOCLIP > 0 allows the task to clip
bad values at DOCLIP * rms
ORDER Order of fit
REFREQ Reference frequency in GHz
< 0 -> header, 0 -> 1 GHz
NOISE Noise in Jy for each freq
0 => 0.1 initially
0 => rms on the plots
FLDSIZE (Flux, freq) in (Jy, GHz)
0 => use source table
DOCONFRM -1.0 1.0 > 0 => replace SU table
values with fit
SNVER -1.0 > 0 -> also correct SN table
INVERS -1.0 > 0 -> correct SNVER-INVERS
SYMBOL 0.0 24.0 Symbol to use on plot
FACTOR 0.0 20.0 Scale plot symbols
PIXRANGE Control the Y plot range
DOTV > 0 => plot on TV, 0 no plots
< 0 => make 2 plot files
GRCHAN 0.0 7.0 TV graphics channel to use
SPECFLUX @ Flux at REFREQ
SPECINDX @ Spectral index
SPECURVE @ Spectral index curvature
HELP SECTION
SOUSP
Task: This task fits fluxes for a source to determine the spectral
index and spectral index curvature:
log10 (flux) = A + SPECINDX * log10(f/f0) +
SPECURVE(1) * [log10(f/f0)]^2 + ...
where A is log10 of the flux at REFREQ, f is the frequency, and
f0 is REFREQ. It then plots the fit in both log and linear space
on the TV or in plot files. It will return the adverbs SPECINDX
and SPECURVE for use in other tasks such as BPASS.
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.
SRCNAME....Name of source ' ' not allowed
CALCODE....SOURCES(1) may occur more than once in the source table
with different calibator codes. CALCODE may then be used
to select which one you want.
' ' => any calibrator code selected
'* ' => any non blank code (cal. only)
'-CAL' => blank codes only (no calibrators)
anything else = calibrator code to select.
NB: The CALCODE test is applied in addition to the other
tests, i.e. SOURCES(1) and QUAL, in the selection of the
source for which to determine the solution.
QUAL.......Source qualifier: -1 => any, 0 is a real value.
DOCLIP.....> 0 -> examine fluxes(if) and drop any more than
DOCLIP(1) times the rms away from the median, all evaluated
in log10(flux(if)), 0 < DOCLIP <= 1 -> 5.
ORDER......<= 1 => fit spectral index only, 2 also fit SPECURVE(1),
3 also fit SPECURVE(2), 4 also fit SPECURVE(3). You will
normally not wish to use more than 2.
REFREQ.....Compute total flux, spectra index and curvature with
reference frequency REFREQ in GHz
0 => use 1 GHz; < 0 => use header frequency
If FLDSIZE is used, REFREQ is set to 1 GHz.
NOISE......Noise value for frequencies 1 up to 64. If FLDSIZE is
not used, then these apply to the fluxes in the SU table
for the named source. Otherwise, they apply to the
fluxes and frequencies listed in FLDSIZE.
0 -> 0.1 Jy for the weighting used in fitting
The error bars in the plots use NOISE(i), if > 0, and the
actual rms otherwise.
FLDSIZE....FLDSIZE(1,i) is the flux for the i'th frequency to be fit
in Jy and FLDSIZE(2,i) is the frequency in GHz. The
number of frequencies to be fit is determined by the
number of FLDSIZE pairs that are both > 0. If all are 0,
then the SU table is used to provide the fluxes for the
various IF frequencies.
DOCONFRM...> 0 => ask after plotting if the SU table values should
be replaced by the fit values - a YES or yes
answer must be given to make this happen. This is
only done if all of FLDSIZE is 0.
<= 0 => do not change the fluxes in the SU table and do
not ask about it.
SNVER......If > 0 and DOCONFRM > 0 and all of FLDSIZE is 0, then
correct SN table version SNVER for new fluxes (if any).
INVERS.....If > SNVER > 0, correct SN table versions SNVER through
INVERS for new fluxes (if any).
SYMBOL.....Choices are
1: Plus sign 13: Star of David
2: Cross (X) 14: Seven-pointed star
3: Circle 15: Eight-pointed star
4: Box 16: Nine-pointed star
5: Triangle 17: Ten-pointed star
6: Diamond 18: 11-pointed star
7: Pentagon 19: 12-pointed star
8: Hexagon 20: 13-pointed star
9: Septagon 21: 14-pointed star
10: Octagon 22: Plus (+) with gap
11: Nine-gon 23: Cross (X) with gap
12: Five pointed star 24: Vertical line
FACTOR.....Scale plot symbols by FACTOR 0 -> 1.
Data points are plotted as symbols, error bars as vertical
lines, and the fit as a connected line.
PIXRANGE...If PIXRANGE(2) > PIXRANGE(1), the plot will only cover
that range in flux. Otherwise it will cover the full
trange of the data (only).
DOTV.......> 0 => plot directly on the TV device, otherwise make a
plot file for later display on one or more devices
(including the TV if desired).
GRCHAN.....Graphics channel (1 - 7) to use for line drawing.
A value of 0 causes more than one graphics channel to be
used.
Returned adverbs
SPECFLUX...Flux at REFREQ
SPECINDX...Spectral index defined above.
SPECURVE...Spectral index curvature parameters based on a reference
frequency of REFREQ GHz and base-10 logarithms.
EXPLAIN SECTION