SPICE User's Guide - IRSA
SPICE User's Guide - IRSA
SPICE User's Guide - IRSA
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<strong>SPICE</strong> User’s <strong>Guide</strong><br />
Flux-calibrated spectrum (*.spect.tbl): The output of the module is the flux calibrated<br />
spectrum. It is written to the output table and displayed in the plot window. An ASCII version<br />
of the file is seen by clicking the View button.<br />
DISCUSSION<br />
This module applies absolute flux calibration to the one-dimensional spectral output file from<br />
Extract. For each separate spectral order in SL and LL and each Echelle order in SH and LH,<br />
Point Source Tune applies adjustments to the shape of the order and corrects by a scaling<br />
constant, in units of electrons/s/Jy, to convert the spectrum to units of Jy. The scaling and<br />
shape adjustments are contained in an input calibration file, fluxcon.tbl. This file contains the<br />
coefficients calculated by fitting an nth-order polynomial, where 1 ≤ n ≤ 5, to the Extract<br />
output of one or more calibration stars so that their observed IRS spectra are forced to match<br />
a model spectrum taken as truth. The ASCII output from Point Source Tune contains five<br />
columns containing the order number, wavelength in microns, flux in units of Jy, uncertainty<br />
in the flux measurement in Jy (currently not suited to derive signal-to-noise ratios), and any<br />
needed flags.<br />
2.7 Extended Source Tune<br />
PURPOSE<br />
The Extended Source Tune module converts the extracted spectrum of extended sources from<br />
units of electrons per second to flux density (Jy). Point Source Tune is used for point sources.<br />
The calibration assumes that the flux is measured over a 28-pixel straight edge aperture in the<br />
low-res modules and over the full slit in the high-res ones. These are the default parameters of<br />
the Extract module with Extended Source extraction. The resulting calibration is only strictly<br />
valid for cases in which the extended source is uniformly bright and covers an area much<br />
larger than the slit. In practice, the calibration will be approximately correct for sources that<br />
are uniform over the width of the slit plus several PSF widths (~6 pixels) on either side.<br />
INPUTS<br />
There are no user inputs for Extended Source Tune.<br />
OUTPUTS<br />
ReTune Results (*.aploss_spect.tbl, *.extsrc.tbl): The output of the module is two spectra.<br />
The first (aploss_spect.tbl) is the flux tuned spectrum (in Jy). The spectrum is derived<br />
<strong>SPICE</strong> Modules 33 Extended Source Tune
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