ObservationStats¶

class gammapy.data.ObservationStats(n_on=None, n_off=None, a_on=None, a_off=None, obs_id=None, livetime=None)[source]¶

Observation statistics.

Class allowing to summarize observation (DataStoreObservation) statistics

Parameters:	n_on : int Number of on events n_off : int Number of off events a_on : float Relative background exposure of the on region a_off : float Relative background exposure of the off region obs_id : int ID of the observation livetime : `Quantity` Livetime of the observation

Attributes Summary

`alpha`	Alpha (on / off exposure ratio)
`background`	Background estimate (float)
`excess`	Excess (float)
`sigma`	Li-Ma significance for observation statistics (float).

Methods Summary

`from_observation`(observation, bg_estimate)	Create from `DataStoreObservation`.
`stack`(stats_list)	Stack (concatenate) list of `ObservationStats`.
`to_dict`(self)	Data as a dict.

Attributes Documentation

alpha¶

Alpha (on / off exposure ratio)

Override member function from Stats to take into account weighted alpha by number of Off events

background¶: Background estimate (float)

\[\mu_\mathrm{bg} = \alpha\ n_\mathrm{off}\]

excess¶: Excess (float)

\[n_\mathrm{ex} = n_\mathrm{on} - \mu_\mathrm{bg}\]

Methods Documentation

classmethod from_observation(observation, bg_estimate)[source]¶

Parameters:	observation : `DataStoreObservation` IACT data store observation bg_estimate : `BackgroundEstimate` Background estimate

classmethod stack(stats_list)[source]¶

Stack (concatenate) list of ObservationStats.

Parameters:	stats_list : list List of `ObservationStats`
Returns:	total_stats : `ObservationStats` Statistics for stacked observation

to_dict(self)[source]¶

Data as a dict.

This is useful for serialisation or putting the info in a table.