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+
+Systematics Uncertainties
+=========================
+
+NMMA currently uses ``--error-budget`` to specify the constant systematic uncertainties to be added to the likelihood quadrature.
+
+However, it is now possible to use systematic error (:math:`\sigma_{sys}`) prior  in form of a freely sampled parameter, time dependent and/or filter dependent systematic error. This can done by specifying the file path using the ``--systematics-file`` in ``lightcurve-analysis`` command.
+
+For more information on systematics error, please refer to the `paper <https://arxiv.org/abs/2410.21978>`__.
+
+The following are the examples of the systematics file:
+
+Example 1: Freely sampled (time independent) systematic error
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In this case the systematic error is freely sampled and is not dependent on time or filter.
+
+.. code:: yaml
+
+  config:
+    withTime:
+      value: false
+      filters:
+        - null
+      time_nodes: 4
+      type: Uniform
+      minimum: 0
+      maximum: 2
+    withoutTime:
+      value: true
+      type: Uniform
+      minimum: 0
+      maximum: 2
+
+Example 2: Time dependent systematic error
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In this configuration, a single systematic error is applied across all filters.
+
+.. code:: yaml
+
+    config:
+      withTime:
+        value: true
+        filters:
+          - null
+        time_nodes: 4
+        type: Uniform
+        minimum: 0
+        maximum: 2
+      withoutTime:
+        value: false
+        type: Uniform
+        minimum: 0
+        maximum: 2
+
+
+Example 3: Time and filter dependent systematic error
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+In this configuration, the ``sdssu`` and ``ztfr`` filters are sampled together for systematic errors, while the ``2massks`` filter is sampled independently. All other filters are grouped and sampled together
+
+.. code:: yaml
+
+    config:
+      withTime:
+        value: true
+        filters:
+          - [sdssu, ztfr]
+          - [2massks]
+          - null
+        time_nodes: 4
+        type: Uniform
+        minimum: 0
+        maximum: 2
+      withoutTime:
+        value: false
+        type: Uniform
+        minimum: 0
+        maximum: 2
+  
+
+Distribution types
+==================
+
+Distribution can be of any of the ``analytical`` prior from `bilby <https://git.ligo.org/lscsoft/bilby>`__.
+Please refer to bilby documentation for more information on the available distribution type and their usage. Only positional arguments are required for any of the distrbutions.