13-18 December 2015
International Conference Centre Geneva
Europe/Zurich timezone

Study of GRB light curve decay indices in the afterglow phase

14 Dec 2015, 17:55
Level 2, Room 7&8 (International Conference Centre Geneva)

Level 2, Room 7&8

International Conference Centre Geneva

17 Rue de Varembé, 1211 Geneva


Mrs Roberta Del Vecchio (Astronomical Observatory of the Jagiellonian University)


In this work we study the distribution of temporal power-law decay indices, $\alpha$, in the Gamma Ray Burst (GRB) afterglow phase, fitted for a sample of $164$ long GRBs with known redshifts using a power-law form. These indices are compared to the values of characteristic afterglow luminosity, $L_a$, the time, $T_a^*$, and the analogous decay index, $\alpha_W$, derived with global light curve fitting using the Willingale et al. (2007) model. This model fitting yields similar distributions of $\alpha_W$ to the fitted $\alpha$, but for several bursts difference between these indices can be significant. Analysis of the ($\alpha$, $L_a$) distribution reveals a weak correlation of these quantities. However, we discovered a significant regular trend when studying distribution of GRB $\alpha$ values at the $L_a$, vs. $T_a^*$ (LT) plane, with a differences of the $\alpha$ parameters below and above the fitted LT correlation line (Dainotti et al. 2008). Study of the presented systematic trend may allow one for constraining the physical models for GRBs. A proposed toy model accounting for this systematics applied to the analyzed GRB distribution results in increasing the LT correlation coefficient.
Collaboration Del Vecchio Roberta, Dainotti Maria Giovanna, Ostrowski Michał

Primary author

Mrs Roberta Del Vecchio (Astronomical Observatory of the Jagiellonian University)


Dr Maria Giovanna Dainotti (Stanford University) Prof. Michał Ostrowski (Astronomical Observatory Jagiellonian University)

Presentation Materials