Generating fake spectra in Xspec

Before starting

Be able to run LHEASOFT, either on your machine or on orfeo.
Be familiar with starting xspec and fitting spectra from the data analysis project.
For reference, the XSpec manual is at http://heasarc.gsfc.nasa.gov/xanadu/xspec/manual/manual.html.

First try at generating a fake spectrum

In these instructions, a semicolon means hit Enter.
Move to your suzaku directory (cd suzaku)
Start xspec
Set up an absorbed powerlaw model with a column density of 2E21 cm-2, a photon index of 2.0, and a normalization of 1.0
model wabs*pow; 0.2; 2.0; 1.0;
Create a fake spectrum
fakeit none; spec1.rmf; spec1.arf; y; pow; ; 1000;
This makes one fake spectrum using the suzaku response files and Poisson statistics. The spectrum is saved as powspec1.fak and is for a 1000 second exposure with no background.
Set the horizontal axis to be energy (setplot energy)
Ignore low and high energies (ignore **-0.4; ignore 5.0-**)
Plot the data on a log scale (plot ldata)
Try fitting the data with the absorbed powerlaw model (fit)
Plot the data and the residuals (plot ldata delchi)
Now you know how to generate fake spectra in xspec and fit them.

Using the apec model to find the oxygen line emission as a function of temperature

The assignment is to use the apec model to generate spectra for various temperatures in the range from 10⁵ K to 10⁷ K, then fit each spectrum to measure the strength of the oxygen O VII and O VIII lines and plot the strength of those lines and their ratio as a function of temperature. To complete the assignment, you will need to generate spectra using fakeit as described above but with an apec or vapec model and then fit those spectra using model that is a sum of vapec and gaussians, as in the data analysis assignment.

Some hints:

The spectra should be generated for a plasma with cosmological element abundances.
You might want to think about how long an exposure you want to simulate and whether or not to use photon statistics.
You might want to think about whether or not you need an absorption component.
The apec model, and xspec in general, use keV for temperatures, not Kelvin. However, your final plot should be in Kelvin. You could also make one in keV if you like.
Astronomers like log scales. You might bear this in mind when picking your set of temperature values. You need enough values to clear show any features in the curves of line strength versus temperature.
You might be able to save some effort using xspec scripts and the 'save model' command, which you can read about in the manual.
If you are familiar with python, you might use matplotlib to plot your results.

You should hand in (not necessarily in this order):

Your plots of line strength and line ratio versus temperature.
A table of the data went into the plot.
A list of the xspec commands that you used to generate one of your fake spectra.
A list of the xspec commands that you used to fit that same spectrum.
A description of the process, including answers to the 'might think abouts' above and a description of your plotted results.