- evn2024@mpifr.de
Support
Contribution
Constraining the structure and the dynamics of Gamma-Ray Bursts with VLBI
Speakers
- Stefano GIARRATANA
Primary authors
- Stefano GIARRATANA (Osservatorio di Brera)
Co-authors
- Dr. Marcello GIROLETTI (INAF Istituto di Radioastronomia)
- Dr. Giancarlo GHIRLANDA (Osservatorio di Brera)
Files
Content
The very long baseline interferometry (VLBI) technique offers unique insights into the structure and dynamics of Gamma-Ray Bursts (GRBs). Specifically, VLBI serves as a fundamental tool for measuring the apparent superluminal expansion (if the GRB is seen on-axis) and proper motion (if the GRB is observed slightly off-axis) of the GRB outflow, enabling constraints on its geometry and characterisation of the circum-burst medium. This complementary information already proved to be crucial in alleviating, or even breaking, the degeneracy in the modelling. In this talk, I will focus on the results from two recent bursts, GRB201015A and GRB221009A. For the former, interferometric observations played a critical role in characterising the density profile of the circum-burst medium, while VLBI observations of GRB221009A, the brightest GRB ever recorded to date, enabled us to measure the size and the expansion of the outflow. Lastly, I will discuss future prospects of radio interferometry in GRB research.