The Use of E_(pk) Decay Rates to Find Standard Candles in GRBs

摘要

We have examined a possible correlation between the decay rate of E_(pk) and the luminosity distance for 15 gammaray bursts (GRB), in an attempt to determine if the decay constant (Φ_0) of the primary pulse within a bust may be used as a distance indicator. We show from physical first principles that the invariant quantity Φ_0d~2 should be a constant if the luminosity of GRBs is indeed a standard candle. We find tentative evidence that this quantity may be constant for clean separable FRED pulses, whereas chaotic pulses with unresolved structure do not yield the expected correlation. This is believed to be due to an inevitable overestimating of Φ_0 that occurs when trying to measure the E_(pk) decay rates of overlapping pulses. This method has the potential of yielding distances and hence luminosities of clean GRBs with separable pulses and may be related to the underlying physics of the lag-luminosity correlation.