Origin and Interpretation of Spectral Lags in GRB Prompt Emission with Multiple Components

Delays in the arrival time of lower-energy to higher-energy gamma-rays, called spectral lags, have been observed in the prompt emission of many long GRBs and are typically not significant in short GRBs. Though the origin of these lags is unclear, they have often been interpreted as the fingerprint of a single emission process. Recent results show that GRB prompt emission may be a mixture of multiple emission components of both thermal and non-thermal origin. Bright short GRB 120323A, known for its intense thermal component in addition to a non-thermal one, displays significant spectral lags. A possible explanation given for this was the thermal and non-thermal emission components peaking in different energy bands and therefore, biasing the cross-correlation function analysis used to measure the lags. In this presentation, I test this theory by deconvolving the emission components in GRB 120323A and measuring the spectral lags in each component individually. I show how this result may impact the interpretation of spectral lags reported in the literature.