Feature #3606

Add spectral bin function

Added by Knödlseder Jürgen almost 4 years ago. Updated almost 4 years ago.

Status:ClosedStart date:04/13/2021
Priority:NormalDue date:
Assigned To:Knödlseder Jürgen% Done:

100%

Category:-
Target version:2.0.0
Duration:

Description

Creating a spectrum in the COMPTEL standard energy bands excluding the 26Al band (1.7-1.9 MeV) the spectral node functions gives unreliable flux and error estimates. For spectral analysis it seems more appropriate to have a spectral bin function that defines a constant intensity within a given energy band.

A class GModelSpectralBins should be added to implement this functionality. The formal of the model definition XML file should be as follows:

<spectrum type="BinFunction">
    <bin>
        <parameter scale="1.0"   name="LowerLimit" min="0.1"   max="1.0e20" value="0.75" free="0"/>
        <parameter scale="1.0"   name="UpperLimit" min="0.1"   max="1.0e20" value="1.0"  free="0"/>
        <parameter scale="1e-07" name="Intensity"  min="1e-07" max="1000.0" value="1.0"  free="1"/>
    </bin>
    <bin>
        <parameter scale="1.0"   name="LowerLimit" min="0.1"   max="1.0e20" value="1.0"  free="0"/>
        <parameter scale="1.0"   name="UpperLimit" min="0.1"   max="1.0e20" value="3.0"  free="0"/>
        <parameter scale="1e-07" name="Intensity"  min="1e-07" max="1000.0" value="0.1"  free="1"/>
    </bin>
</spectrum>

Recurrence

No recurrence.

History

#1 Updated by Knödlseder Jürgen almost 4 years ago

  • Status changed from New to Pull request
  • % Done changed from 0 to 90

I implemented the GModelSpectralBins class, modelled on the GModelSpectralNodes class, but now with statistically independent spectral bins. Within a bin, the spectrum follows a power law, with a spectral index that is the same for all bins. The value of the spectral index is added as an additional parameter to the XML file, as shown below:

<spectrum type="BinFunction">
    <parameter name="Index" scale="-1" value="2.48" min="0.0" max="+5.0" free="0"/>
    <bin>
        <parameter scale="1.0"   name="LowerLimit" min="0.1"   max="1.0e20" value="0.75" free="0"/>
        <parameter scale="1.0"   name="UpperLimit" min="0.1"   max="1.0e20" value="1.0"  free="0"/>
        <parameter scale="1e-07" name="Intensity"  min="1e-07" max="1000.0" value="1.0"  free="1"/>
    </bin>
    <bin>
        <parameter scale="1.0"   name="LowerLimit" min="0.1"   max="1.0e20" value="1.0"  free="0"/>
        <parameter scale="1.0"   name="UpperLimit" min="0.1"   max="1.0e20" value="3.0"  free="0"/>
        <parameter scale="1e-07" name="Intensity"  min="1e-07" max="1000.0" value="0.1"  free="1"/>
    </bin>
</spectrum>

I added unit tests to test the check the validity of the class.

#2 Updated by Knödlseder Jürgen almost 4 years ago

I also added GModelSpectralNodes::error(int&) and GModelSpectralBins::error(int&) method so that the intensity error can be accessed directly.

#3 Updated by Knödlseder Jürgen almost 4 years ago

  • Status changed from Pull request to Closed
  • % Done changed from 90 to 100

Merged into devel.

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