In this paper , we explore time resolved Gamma-Ray Burst ( GRB ) spectra in the context of the synchrotron emission model presented in Lloyd and Petrosian ( 2000 ; LP00 ) .
First , we show that our model - which involves three distinct emission regimes - can provide excellent fits to the time resolved spectra of GRBs , and we present these results for a few bursts .
We then describe how the phenomenological Band spectrum ( Band et al. , 1993 ) can be interpreted in the context of our models based on the value of the low energy photon index \alpha .
We discuss the types of correlations one would expect to observe among the Band parameters if these models are correct .
We then compare these predictions to the existing data , combining a sample of 2,026 time resolved spectra ( from approximately 80 bursts ) .
We show that the correlations found in the data are consistent with the models , and discuss the constraints they place on the emission physics .
In particular , we find a ( \sim 4 \sigma ) negative correlation between the peak of the \nu F _ { \nu } spectrum , E _ { p } , and the low energy photon index \alpha for bursts with -2 / 3 < \alpha < 0 , in contrast to what is predicted by the instrumental effect discussed in LP00 .
We suggest that this correlation is simply due to the mechanism responsible for producing \alpha ’ s above the value of -2 / 3 - namely , a decreasing mean pitch angle of the electrons .
We also show that E _ { p } is correlated with the photon flux , and interpret this as a result of changing magnetic field or characteristic electron energy between emission episodes .
Finally , we discuss the implications our results have on particle acceleration in GRBs , and prospects for further testing these models with the anticipated data from HETE-2 , Swift and GLAST .