ObservationCTA

class gammapy.data.ObservationCTA(obs_id=None, gti=None, events=None, aeff=None, edisp=None, psf=None, bkg=None, pointing_radec=None, observation_live_time_duration=None, observation_dead_time_fraction=None, meta=None)

Bases: object

Container class for an CTA observation

Parameters follow loosely the “Required columns” here: http://gamma-astro-data-formats.readthedocs.io/en/latest/data_storage/obs_index/index.html#required-columns

Parameters:

obs_id : int

Observation ID

gti : GTI

Good Time Intervals

events : EventList

Event list

aeff : EffectiveAreaTable2D

Effective area

edisp : EnergyDispersion2D

Energy dispersion

psf : PSF3D or EnergyDependentMultiGaussPSF or PSFKing

Tabled Point Spread Function

bkg : Background2D or Background3D

Background rate

pointing_radec : SkyCoord

Pointing RA / DEC sky coordinates

observation_live_time_duration : Quantity

Live-time duration in seconds

The dead-time-corrected observation time.

Computed as t_live = t_observation * (1 - f_dead) where f_dead is the dead-time fraction.

observation_dead_time_fraction : float

Dead-time fraction

Defined as dead-time over observation time.

Dead-time is defined as the time during the observation where the detector did not record events: https://en.wikipedia.org/wiki/Dead_time https://adsabs.harvard.edu/abs/2004APh….22..285F

The dead-time fraction is used in the live-time computation, which in turn is used in the exposure and flux computation.

meta : OrderedDict

Dictionary to store metadata

Examples

A minimal working example of how to create an observation from CTA’s 1DC is given in examples/example_observation_cta.py