Glossary
========
.. _glossary_countscube:
.. topic:: Counts cube
A counts cube is a three-dimensional data cube spanned by Right Ascension
or Galactic longitude, Declination or Galactic latitude, and reconstructed
energy. The binning is logarithmic in energy.
.. _glossary_eventlist:
.. topic:: Event list
An event list is a table comprising the reconstructed properties of the
observed events. Each row of the table corresponds to an event. The columns
of the table provide event characteristics, such as trigger time,
reconstructed arrival direction (in Right Ascension and Declination), and
the reconstructed event energy.
.. _glossary_1dc:
.. topic:: First CTA Data Challenge
The goal of the first CTA Data Challenge is to enable the CTA Consortium
Science Working Groups to derive science benchmarks for the CTA Key Science
objectives.
The first CTA Data Challenge should provide quantitative estimates of CTA's
science capabilities that will enable the CTA Consortium Science Working
Groups to evaluate science trade-offs in the future. The first CTA Data
Challenge should also result in numerous show cases, including for example
images, spectra and light curves, that can be used to illustrate CTA's
science case, and that should enrich the CTA outreach material. And the
first CTA Data Challenge should also stimulate the enrichment of the CTA
Science Case.
.. _glossary_gti:
.. topic:: Good Time Interval
A Good Time Interval is a contiguous time period, defined by a start and
a stop time, during which the events can be used for a scientific analysis.
.. _glossary_irf:
.. topic:: Instrument Response Functions
The instrument response functions provide a mathematical description that
links the measured quantities of an event to the physical quantities of
the incident photon. The instrument response functions for CTA are factorised
into the effective area :math:`A_{\rm eff}(p, E, t)` (units :math:`cm^2`),
the point spread function :math:`PSF(p' | p, E, t)`,
and the energy dispersion :math:`E_{\rm disp}(E' | p, E, t)`
following:
.. math::
R(p', E', t' | p, E, t) =
A_{\rm eff}(p, E, t) \times
PSF(p' | p, E, t) \times
E_{\rm disp}(E' | p, E, t)
.. _glossary_moddef:
.. topic:: Model definition file
Source and background model components are defined in ctools by a model
definition file. The model definition file is an ASCII file in XML format.
The format of the model definition file is inspired from, and is
compatible with, the format used by the Fermi-LAT Science Tools.
The general structure of a model definition file is
.. code-block:: xml
Each model component is described by the ```` tag. Each source has
an mandatory spectral and a spatial component (tags ```` and
````) and an optional temporal component (tag ````).
Parameters that should be adjusted in a maximum likelihood fit should be
set to ``free="1"``; otherwise they are hold fixed.
.. _glossary_obs:
.. topic:: Observation
The data are split into observations. Each observation is characterised by
a stable instrument configuration that can be described by an instrument
response function. Observations are also known as runs.
.. _glossary_obsdef:
.. topic:: Observation definition file
Observations are combined in ctools using an observation definition file.
The observation definition file is an ASCII file in XML format.
The format of the observation definition file is illustrated below:
.. code-block:: xml