compute_lightcurve_doublingtime#

gammapy.estimators.utils.compute_lightcurve_doublingtime(lightcurve, flux_quantity='flux')[source]#

Compute the minimum characteristic flux doubling and halving time for the input lightcurve.

Internally calls the compute_flux_doubling function.

The characteristic doubling time is estimated to obtain the minimum variability timescale for the light curves in which rapid variations are clearly evident: for example it is useful in AGN flaring episodes.

This quantity, especially for AGN flares, is often expressed as the pair of doubling time and halving time, or the minimum characteristic time for the rising and falling components respectively.

Parameters:
lightcurveFluxPoints

The lightcurve object.

flux_quantitystr, optional

Flux quantity to use for calculation. Should be ‘dnde’, ‘flux’, ‘e2dnde’ or ‘eflux’. Default is ‘flux’.

Returns:
tableTable

Table of flux doubling/halving and associated error for each energy bin of the lightcurve with axis coordinates at which they were found.

References

Brown et al. (2013), “Locating the γ-ray emission region of the flat spectrum radio quasar PKS 1510−089”

Examples

from gammapy.estimators import FluxPoints
from gammapy.estimators.utils import compute_lightcurve_doublingtime

lightcurve = FluxPoints.read(
    "$GAMMAPY_DATA/estimators/pks2155_hess_lc/pks2155_hess_lc.fits",
    format="lightcurve",
)
doublingtime = compute_lightcurve_doublingtime(lightcurve)