Acceptance of CTA

[micheledoro]

The latest plot that I found about the sensitivity of CTA offaxis is in the CTA webpage https://www.cta-observatory.org/science/cta-performance/#1472563544190-020879e1-468f, that I also report here. Is this useful? Are four points sufficient?

[Jopana]

Yes, and no...

1) Until now, I always assumed that the efficiency was flat until somewhere, and from there exponentially decaying. With this four points, we could assume flat until 0.5, and then exponentially decaying. But we need to see if this makes sense. As far as I remember, the code only 'interpolates' the TGraph given, so if we want to impose something like this, we may need to create a TF1* or make sure to fill the TGraph in an intelligent way (by artificially adding more points)

2) Currently, the code does not take into account any energy dependance. Hence, we need to artificially fix the energy region we are interested. I do not recall now, hod did I do that for the last paper, but probably I picked the energy region where the instrument was the most sensitive... or some arbitrary definition like this.

[micheledoro]

As you see, the energy dependence is quite strong. We should at some point reason whether we can actually forget about it or change the code accordingly. Anyhow. The method with which you include this should be written down in the read è file

[micheledoro]

Do you remember what txt file did you use for the acceptance of CTA? If I run exampleJDinstruments with the CTA file sensitivityCTA500to800.txt the script fails with the message

Error in <HandleInterpreterException>: Trying to dereference null pointer or trying to call routine taking non-null arguments.
Execution of your code was aborted.
In file included from input_line_12:1:
/Users/mdoro/Soft/obsopt_ctapaper/macros/my_instrument.cxx:357:2: warning: null passed to a callee that requires a non-null argument [-Wnonnull]
        functionCameraAcceptance->Draw("same");

[micheledoro]

The error was the two columns of the file were separated by a comma. Removing the comma I could read the file