[Okc-wp4] EO meeting: 4th of November

[Davide Gizzi]

Dear all,


a kind reminder of the EO meeting, today at 13:15.


Kind regards


Ana Sagués Carracedo & Davide Gizzi



________________________________
From: Davide Gizzi
Sent: Thursday, October 28, 2021 12:06:35 PM
To: Okc-wp4 at fysik.su.se; people at nordita.org
Cc: Eliot Henri Roger Ayache
Subject: EO meeting: 4th of November


Dear all,



our next EO meeting will take place next Thursday, 4th of November, at 13:15  (CET) via Zoom.

To join access: https://stockholmuniversity.zoom.us/j/67378581617


The speaker is Eliot Henri Roger Ayache, a postdoc who recently joined Anders Jerkstrand's Supernova group. He did his PhD at the University of Bath (UK) in Hendrik van Eerten's group, working on numerical modeling of GRBs afterglow. His research currently focuses on the late time dynamics and emission of kilonovae, as well as on the kilonova/GRB jet interaction.


Below is the title and abstract of the talk.



GRB afterglows from early to late times or how to accurately capture non-thermal emission using moving meshes


Recent years have seen massive breakthroughs in the observations of gamma-ray bursts and other high-energy astrophysical transients. Dynamical jet simulations have progressed to a point where it is now becoming possible to fully numerically resolve gamma-ray burst (GRB) jet evolution across scales. However, the modeling of radiative emission is currently lagging behind and makes for a bottleneck severely limiting our efforts to fully interpret the physics of GRBs in the multi-messenger era. In this talk, I will present new numerical developments to resolve this discrepancy and focus on providing insights into GRB afterglow physics. Using numerical simulations, we set out to understand the impact of the presence of multiple emission sites on afterglow light curves. We also investigate the trans-relativistic evolution of the jet and poorly understood behaviour of the spectral breaks in the radiation as the jet decelerates. In order to do this, we developed a new method for the local numerical calculation of non-thermal emission in relativistic shocks. This method combines a moving mesh finite-volume code with a local description of particle acceleration and corresponding synchrotron process in a code called GAMMA. The resulting improvements in computational efficiency, and subsequent ability to reach very high spatial resolution, enables the accurate simulation of GRB afterglow spectral evolution from early to late times. Using these simulations, we can: (i) investigate the short timescale variability of GRB afterglow light curves such as the origin of flares, (ii) quantify the expected deviations of the approximate analytical methods for the calculation of emissivity that are currently in use in the GRB afterglow community.



Hope to see you there!


Ana Sagués Carracedo & Davide Gizzi




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