Most of my interactive analysis, testing, and research scripts are
done with ISIS. These grow out
of research projects, but have (or may) become supported CIAO-contributions.
ACIS/Grating Light Curve; a suite to compute light or phase curves
from ACIS/grating data (HETG or LETG).
Direct fitting of Helium-like line ratios, for density and temperature
|44 Boo light curve (black), hard and soft light curves
(blue or red), hardness ratio (blue & red),
soft-filtered phase curve (red), and exposure function.
||Simulated O VII triplet (black), fit (red), residuals (black),
and confidence contours (red, green, blue) of G=(f+i)/r
(y-axis) and R=f/i (x-axis) ratios.
- tgplot.sl: Interactive browsing and
measurement of Chandra grating spectra. Defines thermal plasma model
for line identification, measures flux in regions, produces line-lists
Demos and Examples
- Simulation and line ratios: A demonstration of some key
ISIS functions for use in simulating spectra, measuring lines, and
comparing measured ratios to theoretical isothermal values (2007.05).
The full ISIS/S-Lang script
Software in Progress
Some analysis software in various stages of development are listed
below. They are available as-is on request (i.e., limited
documentation and support; subject to change.)
- CLP.sl: Composite Line Profile analysis, for summing many
weak lines for improved centroids vs phase or time. An example was
shown in a
Newsletter (Figure 16).
- zofind.sl: Interactively find the
zero order centroid via the intersection of a grating arm's events and
the CCD streak events. This requires the
GTK module and its
interactive filter function.
- lfree.sl: Line-free region and continuum modeling support.
Determines model- and instrument-dependent line-free regions from APED
plasma models in ISIS.
The figure shows two different thermal models in black and gray (at
instrumental resolution), and continuum in blue, with line-free
intervals in red, as determined from a ratio of line plus continuum to
continuum-only models. Line-free regions are returned as bin-lists
which can then be "noticed" and fits done to continuum-only bins in
order to derive continuum models for more accurate line-flux
measurements. The regions are computed for any given plasma model,
instrumental response, and selectable significance threshold. The
continuum model may be chosen from the true continuum or true plus
pseudo-continuum (sum or weak lines), as available in the
This page was last updated Nov 16, 2017 by David P. Huenemoerder. To comment on it or the material presented here, send email to email@example.com.