Speaker
Mrs
Roberta Del Vecchio
(Astronomical Observatory of the Jagiellonian University)
Description
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.
Author
Mrs
Roberta Del Vecchio
(Astronomical Observatory of the Jagiellonian University)
Co-authors
Dr
Maria Giovanna Dainotti
(Stanford University)
Prof.
Michał Ostrowski
(Astronomical Observatory Jagiellonian University)
