Observation¶
-
class
gammapy.data.
Observation
(obs_id=None, obs_info=None, gti=None, aeff=None, edisp=None, psf=None, bkg=None, events=None, obs_filter=None)[source]¶ Bases:
object
In-memory observation.
- Parameters
- obs_idint
Observation id
- obs_infodict
Observation info dict
- aeff
EffectiveAreaTable2D
Effective area
- edisp
EnergyDispersion2D
Energy dispersion
- psf
PSF3D
Point spread function
- bkg
Background3D
Background rate model
- gti
GTI
Table with GTI start and stop time
- events
EventList
Event list
- obs_filter
ObservationFilter
Observation filter.
Attributes Summary
A lazy FITS data descriptor.
A lazy FITS data descriptor.
A lazy FITS data descriptor.
Fixed pointing info for this observation (
FixedPointingInfo
).Observation muon efficiency.
Dead-time fraction (float).
Live-time duration in seconds (
Quantity
).Observation time duration in seconds (
Quantity
).Observatory location (
EarthLocation
).Pointing ALT / AZ sky coordinates (
SkyCoord
).Pointing RA / DEC sky coordinates (
SkyCoord
).Pointing zenith angle sky (
Quantity
).A lazy FITS data descriptor.
Target RA / DEC sky coordinates (
SkyCoord
).Observation start time (
Time
).Observation stop time (
Time
).Methods Summary
check
([checks])Run checks.
create
(pointing[, obs_id, livetime, tstart, …])Create an observation.
peek
([figsize])Quick-look plots in a few panels.
select_time
(time_interval)Select a time interval of the observation.
Attributes Documentation
-
aeff
¶ A lazy FITS data descriptor.
- Parameters
- cachebool
Whether to cache the data.
-
bkg
¶ A lazy FITS data descriptor.
- Parameters
- cachebool
Whether to cache the data.
-
edisp
¶ A lazy FITS data descriptor.
- Parameters
- cachebool
Whether to cache the data.
-
events
¶
-
fixed_pointing_info
¶ Fixed pointing info for this observation (
FixedPointingInfo
).
-
gti
¶
-
muoneff
¶ Observation muon efficiency.
-
observation_dead_time_fraction
¶ Dead-time fraction (float).
Defined as dead-time over observation time.
Dead-time is defined as the time during the observation where the detector didn’t record events: https://en.wikipedia.org/wiki/Dead_time https://ui.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.
-
observation_live_time_duration
¶ Live-time duration in seconds (
Quantity
).The dead-time-corrected observation time.
Computed as
t_live = t_observation * (1 - f_dead)
wheref_dead
is the dead-time fraction.
-
observation_time_duration
¶ Observation time duration in seconds (
Quantity
).The wall time, including dead-time.
-
observatory_earth_location
¶ Observatory location (
EarthLocation
).
-
psf
¶ A lazy FITS data descriptor.
- Parameters
- cachebool
Whether to cache the data.
Methods Documentation
-
classmethod
create
(pointing, obs_id=0, livetime=None, tstart=None, tstop=None, irfs=None, deadtime_fraction=0.0, reference_time='2000-01-01')[source]¶ Create an observation.
User must either provide the livetime, or the start and stop times.
- Parameters
- pointing
SkyCoord
Pointing position
- obs_idint
Observation ID as identifier
- livetime~astropy.units.Quantity`
Livetime exposure of the simulated observation
- tstart
Quantity
Start time of observation w.r.t reference_time
- tstop
Quantity
w.r.t reference_time Stop time of observation
- irfsdict
IRFs used for simulating the observation:
bkg
,aeff
,psf
,edisp
- deadtime_fractionfloat, optional
Deadtime fraction, defaults to 0
- reference_time
Time
the reference time to use in GTI definition
- pointing
- Returns
- obs
gammapy.data.MemoryObservation
- obs
-
peek
(figsize=(12, 10))[source]¶ Quick-look plots in a few panels.
- Parameters
- figszietuple
Figure size
-
select_time
(time_interval)[source]¶ Select a time interval of the observation.
- Parameters
- time_interval
astropy.time.Time
Start and stop time of the selected time interval. For now we only support a single time interval.
- time_interval
- Returns
- new_obs
Observation
A new observation instance of the specified time interval
- new_obs