Commit 503850526be1d142a7f8e044d82977a5039f900c
1 parent
fb8d78c8
Add information to User Manual about setting of instrument specific scale factor…
…s in the model definition XML file
Showing
1 changed file
with
40 additions
and
0 deletions
doc/source/users/user_manual/models_implementation.rst
| ... | ... | @@ -94,3 +94,43 @@ term will be appended to each ``<parameter>`` tag. |
| 94 | 94 | made some modifications. |
| 95 | 95 | Nevertheless, the format used by the Fermi/LAT ScienceTools is also |
| 96 | 96 | supported. |
| 97 | + | |
| 98 | +.. note:: | |
| 99 | + | |
| 100 | + To cope with cross-calibration uncertainties between different instruments, | |
| 101 | + instrument specific scaling factors :math:`S_{\rm inst}` can be multiplied | |
| 102 | + to the source models according to | |
| 103 | + | |
| 104 | + .. math:: | |
| 105 | + M(p,E,t) = S_{\rm inst} \times M_{\rm spatial}(p|E) \times M_{\rm spectral}(E) \times M_{\rm temporal}(t) | |
| 106 | + | |
| 107 | + and an example for the specification of scale factors :math:`S_{\rm CTA}` for | |
| 108 | + ``CTA`` and :math:`S_{\rm HESS}` for H.E.S.S. in the | |
| 109 | + :ref:`model definition XML file <glossary_moddef>` | |
| 110 | + is shown below. | |
| 111 | + In the example, :math:`S_{\rm CTA}` is fixed to :math:`1`, hence the | |
| 112 | + scale factor could also be omitted from the XML file. | |
| 113 | + The scale factor :math:`S_{\rm HESS}` is set to :math:`1.1` and will be | |
| 114 | + fitted during the model fit. | |
| 115 | + | |
| 116 | + .. code-block:: xml | |
| 117 | + | |
| 118 | + <?xml version="1.0" standalone="no"?> | |
| 119 | + <source_library title="source library"> | |
| 120 | + <source name="Crab" type="PointSource"> | |
| 121 | + <spectrum type="PowerLaw"> | |
| 122 | + <parameter name="Prefactor" scale="1e-16" value="5.7" min="1e-07" max="1000.0" free="1"/> | |
| 123 | + <parameter name="Index" scale="-1" value="2.48" min="0.0" max="+5.0" free="1"/> | |
| 124 | + <parameter name="PivotEnergy" scale="1e6" value="0.3" min="0.01" max="1000.0" free="0"/> | |
| 125 | + </spectrum> | |
| 126 | + <spatialModel type="PointSource"> | |
| 127 | + <parameter name="RA" scale="1.0" value="83.6331" min="-360" max="360" free="0"/> | |
| 128 | + <parameter name="DEC" scale="1.0" value="22.0145" min="-90" max="90" free="0"/> | |
| 129 | + </spatialModel> | |
| 130 | + <scaling> | |
| 131 | + <instrument name="CTA" scale="1.0" min="0.1" max="10.0" value="1.0" free="0"/> | |
| 132 | + <instrument name="HESS" scale="1.0" min="0.1" max="10.0" value="1.1" free="1"/> | |
| 133 | + </scaling> | |
| 134 | + </source> | |
| 135 | + </source_library> | |
| 136 | + | ... | ... |