Interpreting the Results
Now that you have a good fit of the data, you need to step back and
figure out what those results mean. Recall that your goal was to
determine some of the elements in a supernova explosion. Armed with the
best-fit models for those three emission lines, you are ready to
connect your model to the physical realm.
Your first task is to write down the energy where the central peaks
occur for each of your three lines. Recall that this information can be
found in the Xspec command window look for the three "LineE" values in
the results table. You may need to either scroll up in the command
window or enlarge the window to see all of the values.
The table below lists some of the line transitions that will produce photons in the 0.2 to 5.0 keV energy range. The transitions are from ions of different elements. Try to find the ions that produced the three lines that you modeled. (In one case it might be a toss-up between two, just pick the one that's closest in energy to the best-fit line energy.)
|C5+ ||0.37 keV
||C4+ ||0.30 keV|
|N6+ ||0.50 keV
||N5+ ||0.42 keV|
|O7+ ||0.65 keV
||O6+ ||0.55 keV|
|F8+ ||0.83 keV
||F7+ ||0.77 keV|
|Ne9+ ||1.02 keV
||Ne8+ ||0.91 keV|
|Na10+ ||1.23 keV
||Na9+ ||1.11 keV|
|Mg11+ ||1.47 keV
||Mg10+ ||1.33 keV|
|Al12+ ||1.72 keV
||Al11+ ||1.57 keV|
|Si13+ ||2.00 keV
||Si12+ ||1.84 keV|
|S15+ ||2.61 keV
||S14+ ||2.43 keV|
|Ar17+ ||3.30 keV
||Ar16+ ||3.10 keV|
|Ca19+ ||4.08 keV
||Ca18+ ||3.86 keV|
Answer these questions about your results:
You may need to consult a periodic table of the elements here
is an online periodic table if you need it: WebElements.com (http://www.webelements.com/).
- What elements are present in the supernova spectrum?
- What is the atomic number for each element in your spectrum?
(The atomic number is equal to the number of protons in the nucleus
of the element.)
- Recall that the numbers in the superscripts of the ion names
(i.e., "5+", "9+", "14+", etc.) indicate how many electrons the ion
has lost. Using the atomic weight and number of electrons lost, how
many electrons do your elements have left?