The most violent cosmic explosions in the Universe produce gamma ray bursts, photon flashes of very short duration but which are extremely energetic. And two of them have just broken the current energy record, thus confirming that the energies of these gamma ray emissions could be at least 1000 billion times highr than those in visible light !
These detections prove for the first time that in these gamma ray burst are particles accelerated to extreme energies. And they also highlight the fact that these particles are still there, or were created a long time after the initial burst.
The most likely hypothesis is that the original explosion led to the creation of a plasma jet : when this jet interacts with the interstellar medijum it slows down and creates a shock wave which then behaves like a « cosmic ray accelerator ».
These results, found by international research teams [1], including CNRS scientists, as well as those from the Paris Observatory - PSL, using a variety of observational techniques [2], can be found in three papers published in the November 20th 2019 issue of the journal Nature.
References
- A very-high-energy component deep in the γ-ray burst afterglow. H.E.S.S. Collaboration, Abdalla et al. Nature, le 20 novembre 2019.
- Observation of inverse Compton emission from a long γ-ray burst. Veres et al. Nature, le 20 novembre 2019.
- Teraelectronvolt emission from the γ-ray burst GRB 190114C. MAGIC Collaboration, Acciari et al. Nature, le 20 novembre 2019.
The press alert on the CNRS site
Premières détections de sursauts gamma à très haute énergie (First detection of verey high energy gamma ray bursts)
[1] In France have participated in this work scientists from the Centre de physique des particules de Marseille (CNRS / Aix-Marseille Université), du Centre d’études nucléaires de Bordeaux Gradignan (CNRS / Université de Bordeaux), de l’Institut de planétologie et d’astrophysique de Grenoble (CNRS / Université Grenoble Alpes), de l’Institut de recherche sur les lois fondamentales de l’Univers (CEA), du laboratoire « Astroparticule et cosmologie » (CNRS / Université Paris Diderot / CEA / Observatoire de Paris - PSL), du laboratoire « Astrophysique, interprétation, modélisation » (CNRS / CEA / Université Paris Diderot), du Laboratoire d’Annecy de physique des particules (CNRS / Université de Savoie Mont Blanc), du Laboratoire de physique nucléaire et de hautes énergies (CNRS / Sorbonne Université), du laboratoire « Galaxies, étoiles, physique, instrumentation » (Observatoire de Paris - PSL / CNRS), du Laboratoire Leprince-Ringuet (CNRS / Ecole polytechnique), du Laboratoire Univers et particules de Montpellier (CNRS / Université de Montpellier), du Laboratoire Univers et théories (Observatoire de Paris - PSL / CNRS).
[2] Including the two telescope arrays H.E.S.S. and MAGIC.