Relationship between pulse width and energy in GRB 060124: from X-ray to gamma-ray bands

Abstract

GRB 060124 is the first event that both prompt and afterglow emission were observed simultaneously by the three \emph{Swift} instruments. Its main peak also triggered Konus-Wind and HETE-II. Therefore, investigation on both the temporal and spectral properties of the prompt emission can be extended to X-ray bands. We perform a detailed analysis on the two well identified pulses of this burst, and find that the pulses are narrower at higher energies, and both X-rays and gamma-rays follow the same $w - E$ relation for an individual pulse. However, there is no a universal power-law index of the $w - E$ relation among pulses. We find also that the rise-to-decay ratio $r/d$ seems not to evolve with $E$ and the $r/d$ values are well consistent with that observed in typical GRBs. The broadband spectral energy distribution also suggest that the X-rays are consistent with the spectral behavior of the gamma-rays. These results indicates that the X-ray emission tracks the gamma-ray emission and the emissions in the two energy bands are likely to be originated from the same physical mechanism.