EXTOPT -- Standard optimal extraction based upon the paper
Horne, K, 1986, PASP, 98, 609.
EXTOPT fits polynomials to the fraction of flux falling into each column.
These are then used to compute the optimal weights and reject cosmic rays.
The background should have been estimated with 'skyfit'.
Parameters:
IMAGE -- The data file for extraction.
FLAT -- Contains balance factors which when multiplied into
the data correct for short scale sensitivity variations.
DLOAD -- TRUE if dark frame is required.
DARK -- Dark frame representing counts unaffected by slit
profile. This will be subtracted off data before applying
the balance factors.
REGION -- Contains the object region limits. This file should
have been generated by 'regpic' or 'skymov'.
SKY -- Contains fits to the background sky in the region of
the object. Produced by 'skyfit'.
SPECT -- The output file for both the spectrum and the uncertainty
estimates.
YSTART,YEND -- The Y pixel limit of the extraction.
READOUT -- The readout noise of the detector in RMS data units/pixel
PHOTON -- The number of detected photons = electrons per data number.
OLD -- True if you want to use an old profile fit. This is an option
generally used when extracting arc spectra at the same position
as an object.
If .NOT.OLD
NPOLY -- number of terms for profile polynomial fits.
THRESH -- threshold for poly fits.
NBLOCK -- number of rows to add to give one block
for profile fitting stage.
NMED -- median filter width. This is used to filter the profile
sums before they are divided into the profile to obtain
fractions. Use it to reject cosmic rays, but be careful with
sources with many narrow lines.
PROFIT -- If OLD = .TRUE., name of old profile fit file.
If OLD = .FALSE., name of new profile fit file.
PNEW --
ZAPRATS -- .TRUE. then outlying points are ignored. Should not be used
if profile does not represent frame to be extracted (e.g.
arc or sky frame)
If ZAPRATS
RATLO -- Lower outlier zap threshold
RATHI -- Upper outlier zap threshold
EPS -- Fudge factor to avoid silly rejections. On high signal-to-noise
data you can get very close fits but still be several sigma out.
EPS imposes a lower limit to the fractional deviation required
for a point to be rejected.
VMAX -- Maximum value acceptable (to partially cope with saturated data)
PLOT -- .TRUE. if you want plots
DEVICE -- Plot device
If
PNEW -- File name of profile fit if STORE = .TRUE.
This command belongs to the classes: extract , fitting