Add a "Known issue" about selecting a too coarse spatial (and spectral) binning.

Jürgen Knödlseder
1 parent 9e6fd31a
Showing 1 changed file with 13 additions and 0 deletions
doc/source/issues.rst
@@ -7,6 +7,7 @@ Below you will find a list of known issues.
  
 - :ref:`Broken power law has unreliable errors <issues_bplaw>`
 - :ref:`Errors become unreliable when fitting the pivot energy <issues_pivot>`
+- :ref:`Binned analysis is biased when using coarse binning <issues_binned>`
  
  
 .. _issues_bplaw:
@@ -33,3 +34,15 @@ Below you will find a list of known issues.
    parameters of the model to assure non-degeneracy of the free
    parameters.
  
+.. _issues_binned:
+
+.. topic:: Binned analysis is biased when using coarse binning
+
+   When performing a binned or stacked analysis you should make sure
+   that the spatial and spectral binning is sufficiently fine grained.
+   The spatial binning should be better than the best angular resolution
+   over the energy range of interest. Use a typical value of 0.02 degrees.
+   For the spectral binning, use at least 5 bins per decade.
+   If the binning is too coarse, the spectral parameters will be biased.
+   For example, a spectral hardening is observed when using a coarser
+   spatial binning.