INTEGRAL detects a GRB with a concurrent fast optical flux rise
Following the trigger from the INTEGRAL Burst Alert System (IBAS) of GRB
190919B (top left), the F/Photometric Robotic Atmospheric Monitor (FRAM)
30-cm robotic telescope, part of the Auger Observatory in Malargüe,
Argentina, obtained a series of images which revealed a bright optical
afterglow (top right). A careful analysis of the INTEGRAL/IBIS gamma-ray
data revealed a faint flare contemporaneous to the first of the two peak
profiles (bottom left) that fit the optical time profile (bottom
right). This suggests that the first peak is a result of the prolonged
gamma-ray burst internal engine activity. The emission of the second
peak has all the properties of a relativistic shock wave spreading into
the interstellar medium, known as afterglow. The first peak may not seem
strictly necessary in the optical light curve fit, but the steep rise of
the afterglow emission cannot be explained properly with a physical
model, so another component is needed.
Credits:
"GRB 190919B: Rapid optical rise explained as a flaring activity",
Martin Jelínek, Martin Topinka, Sergey Karpov, Alžběta Maleňáková, Y.-D.
Hu, Michela Rigoselli, Jan Štrobl, Jan Ebr, Ronan Cunniffe, Christina
Thoene, Martin Mašek, Petr Janeček, Emilio Fernandez-García, David
Hiriart, William H. Lee, Stanislav Vítek, René Hudec, Petr Trávníček,
Alberto J. Castro-Tirado, Michael Prouza
2022, A&A, in press,
https://arxiv.org/abs/2203.11059
https://doi.org/10.1051/0004-6361/202143010
