GTI

class gammapy.data.GTI(table)

Bases: object

Good time intervals (GTI) Table.

Data format specification: GTI

Note: at the moment dead-time and live-time is in the EVENTS header … the GTI header just deals with observation times.

Parameters

tableTable

GTI table

Examples

Load GTIs for a H.E.S.S. event list:

>>> from gammapy.data import GTI
>>> gti = GTI.read('$GAMMAPY_DATA/hess-dl3-dr1//data/hess_dl3_dr1_obs_id_023523.fits.gz')
>>> print(gti)
GTI info:
- Number of GTIs: 1
- Duration: 1687.0 s
- Start: 53343.92234009259 MET
- Start: 2004-12-04T22:08:10.184 (time standard: TT)
- Stop: 53343.94186555556 MET
- Stop: 2004-12-04T22:36:17.184 (time standard: TT)

Load GTIs for a Fermi-LAT event list:

>>> gti = GTI.read("$GAMMAPY_DATA/fermi-3fhl-gc/fermi-3fhl-gc-events.fits.gz")
>>> print(gti)
GTI info:
- Number of GTIs: 39042
- Duration: 183139597.9032163 s
- Start: 54682.65603794185 MET
- Start: 2008-08-04T15:44:41.678 (time standard: TT)
- Stop: 57236.96833546296 MET
- Stop: 2015-08-02T23:14:24.184 (time standard: TT)

Attributes Summary

time_delta	GTI durations in seconds (Quantity).
time_ref	Time reference (Time).
time_start	GTI start times (Time).
time_stop	GTI end times (Time).
time_sum	Sum of GTIs in seconds (Quantity).

Methods Summary

copy(self)
create(start, stop[, reference_time])	Creates a GTI table from start and stop times.
read(filename[, hdu])	Read from FITS file.
select_time(self, time_interval)	Select and crop GTIs in time interval.
stack(self, other)	Stack with another GTI.
union(self)	Union of overlapping time intervals.
write(self, filename, \*\*kwargs)	Write to file.

Attributes Documentation

time_delta

GTI durations in seconds (Quantity).

time_ref

Time reference (Time).

time_start

GTI start times (Time).

time_stop

GTI end times (Time).

time_sum

Sum of GTIs in seconds (Quantity).

Methods Documentation

copy(self)

classmethod create(start, stop, reference_time='2000-01-01')

Creates a GTI table from start and stop times.

Parameters

startQuantity

start times w.r.t. reference time

stopQuantity

stop times w.r.t. reference time

reference_timeTime

the reference time to use in GTI definition

classmethod read(filename, hdu='GTI')

Read from FITS file.

Parameters

filenamepathlib.Path, str

Filename

hdustr

hdu name. Default GTI.

select_time(self, time_interval)

Select and crop GTIs in time interval.

Parameters

time_intervalastropy.time.Time

Start and stop time for the selection.

Returns

gtiGTI

Copy of the GTI table with selection applied.

stack(self, other)

Stack with another GTI.

This simply changes the time reference of the second GTI table and stack the two tables. No logic is applied to the intervals.

Parameters

otherGTI

GTI to stack to self

Returns

new_gtiGTI

New GTI

union(self)

Union of overlapping time intervals.

Returns a new GTI object.

Intervals that touch will be merged, e.g. (1, 2) and (2, 3) will result in (1, 3).

write(self, filename, **kwargs)

Write to file.