2008/06/07 by Fu-Wen Zhang, Fu‐Wen Zhang
Physics and Astronomy · #Astrophysics #Energy (signal processing) #Galaxy #Gamma-ray burst #Gamma-ray bursts and supernovae #Lag #Light curve #Luminosity #Optics #Physics #Population #Pulse (music) #Quantum mechanics #astro-ph
paper · pdf · doi:10.1086/590951
26 pages, 10 figures, 3 tables, accepted for publication in ApJ
arxiv created 2008/06/07 · openalex publication_date 2008/09/26 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
It has been recently argued that low-luminosity gamma-ray bursts (LL-GRBs) are likely a unique GRB population. Here, we present systematic analysis of the light-curve characteristics from X-ray to gamma-ray energy bands for the two prototypical LL-GRBs, 980425 and 060218. It is found that both the pulse width ( w ) and the ratio of the rising width to the decaying width ( r / d ) of theses two bursts are energy-dependent over a broad energy band. There exists a significant trend that the pulses tend to be narrower and more symmetrical at higher energy bands for the two events. Both the X-rays and the gamma-rays follow the same w - E and r / d - E relations. These facts may indicate that the X-ray emission tracks the gamma-ray emission, and both are likely to originate from the same physical mechanism. Their light curves show significant spectral lags. We calculate the three types of lags with the pulse peaking time ( t peak ), the pulse centroid time ( t cen ), and the cross-correlation function (CCF). The derived t peak and t cen are power-law functions of energy. The lag calculated by CCF is strongly correlated with that derived from t peak . However, the lag derived from t cen correlates less with that derived from t peak and CCF. The energy dependence of the lags is shallower at higher energy bands. These characteristics are consistent with that observed in typical long-lag, wide-pulse GRBs, suggesting that GRBs 980425 and 060218 may share a similar radiation physics with them.