We report on observations of correlated behavior between the prompt \gamma -ray and optical emission from GRB 080319B , which confirm that ( i ) they occurred within the same astrophysical source region and ( ii ) their respective radiation mechanisms were dynamically coupled .
Our results , based upon a new cross-correlation function ( CCF ) methodology for determining the time-resolved spectral lag , are summarized as follows .
First , the evolution in the arrival offset of prompt \gamma -ray photon counts between Swift-BAT 15-25 keV and 50-100 keV energy bands ( intrinsic \gamma -ray spectral lag ) appears to be anti-correlated with the arrival offset between prompt 15-350 keV \gamma -rays and the optical emission observed by TORTORA ( extrinsic optical/ \gamma -ray spectral lag ) , thus effectively partitioning the burst into two main episodes at \sim T + 28 \pm 2 sec .
Second , the rise and decline of prompt optical emission at \sim T + 10 \pm 1 sec and \sim T + 50 \pm 1 sec , respectively , both coincide with discontinuities in the hard to soft evolution of the photon index for a power law fit to 15-150 keV Swift-BAT data at \sim T + 8 \pm 2 sec and \sim T + 48 \pm 1 sec .
These spectral energy changes also coincide with intervals whose time-resolved spectral lag values are consistent with zero , at \sim T + 12 \pm 2 sec and \sim T + 50 \pm 2 sec .
These results , which are robust across heuristic permutations of Swift-BAT energy channels and varying temporal bin resolution , have also been corroborated via independent analysis of Konus-Wind data .
This potential discovery may provide the first observational evidence for an implicit connection between spectral lags and GRB emission mechanisms in the context of canonical fireball phenomenology .
Future work includes exploring a subset of bursts with prompt optical emission to probe the unique or ubiquitous nature of this result .