Conveners
High and Very High Energy Emission from Gamma-Ray Bursts: Block 1
- Francesco Longo (University of Trieste and INFN, Trieste)
- Fabian Schüssler (IRFU / CEA Paris-Saclay)
High and Very High Energy Emission from Gamma-Ray Bursts: Block 2
- Francesco Longo (University of Trieste and INFN, Trieste)
- Fabian Schüssler (IRFU / CEA Paris-Saclay)
Description
GeV and TeV observations of gamma-ray bursts (GRBs) gamma-ray and ground based telescopes over the past decade have opened a new era in the study of GRBs. This session will discuss recent observations of GRBs at GeV and TeV energies and their relation to the prompt < ~ MeV emission and the long-lived afterglow emission. The theoretical implications of these observations will be also discussed, which range from the progenitor nature to the prompt GRB emission mechanism and outflow Lorentz factor and composition, through the GRB jet launching and acceleration mechanism, to particle acceleration in collisionless shocks or magnetic reconnection, constraints on Lorentz invariance violation and the Extragalactic Background light. The session will also discuss the prospects of GRB detection by the future MeV to TeV telescopes.
The detection of gamma-ray bursts (GRBs) is one of the main scientific targets pursued by the MAGIC collaboration since almost 20 years. The MAGIC telescopes were specifically designed for this purpose: the main figures of merit are the fast slewing speed (7deg/s), the low energy threshold (~50 GeV at zenith) and the high sensitivity in the low energy regime. These features make MAGIC one of...
Since their discovery in the late 1960s Gamma-Ray Burst (GRB) emission has been deeply investigated with the help of the huge amount of data collected covering the entire electromagnetic spectrum. This large and broadband dataset was essential to constitute a general picture describing the GRB physics, revealing the most credible underlying physical processes and environmental conditions...
In the last few years, gamma-ray bursts (GRBs) have been detected at Very High Energy (>100 GeV) gamma rays for the first time since their initial discovery half a century ago. This breakthrough occurred thanks to years of technical and strategic improvements (as well as a bit of good luck). In this talk, I will give an overview of the H.E.S.S. GRB program — how H.E.S.S. follows up GRBs, how...
Major advancements in the study of gamma-ray bursts (GRBs) have arisen in the last few years thanks to the recent detections at very high energy (VHE). In this contribution, the observation of GRB 190829A at VHEs with H.E.S.S. is presented. This GRB is one of the closest-ever detected with a redshift z~0.08, a characteristic that allowed an extended temporal detection from 4 hours to 56 hours...
Recent detections of gamma-ray bursts (GRBs) at energies above 100 GeV demonstrate that imaging atmospheric Cherenkov telescopes (IACT) operating in the very high energy range (VHE; E > 100 GeV) can provide insight into the physics of GRBs. By searching for the highest-energy photons emitted by GRBs, these telescopes can help answer questions about the particle acceleration and emission...
Satellites and imaging atmospheric Cherenkov telescopes (IACTs) have shown that gamma-ray bursts (GRBs) are capable of producing very-high-energy photons— most notably GRB 190114C, observed up to 1 TeV by the MAGIC telescopes approximately one minute after triggering the Fermi GBM and Swift BAT satellites. Particularly suited to such searches and follow-up studies is the High-Altitude Water...
Gamma-Ray Bursts (GRBs) are energetic transients originating in a violent explosion of a massive star or merger of two compact objects. These explosions create relativistic blastwave whose expansion leads to external shocks. The emission thus produced is the afterglow observed in
GRBs after the prompt emission. The properties of the emitting region i.e. non-thermal
particle spectrum,...
The precedented multi-messenger campaign launch by the gravitational wave (GW) signal GW170817 and the quasi-simultaneous gamma-ray burst GRB170817A, enabled the study of the various transient counterparts, over different energy bands and timescales, and confirmed for the first time, the hypothesis that binary neutron starts are the progenitor of at least a sub-sample of short GRBs, among many...
After more than 14 years activity, the AGILE satellite continues its exploration of the high-energy sky, investigating galactic and extragalactic sources in the hard X- and gamma-ray energy range. Among its scientific targets, Gamma-Ray Bursts (GRBs) represent one of the most interesting topics. In particular, the AGILE minicalorimeter (MCAL; 0.4-100 MeV) offers the opportunity to detect GRBs...
The Fermi Gamma-ray Space Telescope has provided unique insights into the Universe’s biggest explosions over the past 13 years. With thousands of gamma-ray bursts (GRBs) detected by the Gamma-ray Burst Monitor (GBM) and hundreds by the Large Area Telescope (LAT), we have studied the properties of the populations of these events and obtained unique insights into their emission mechanisms,...
This talk will provide an overview of our current knowledge and understanding of high energy (~0.1-100 GeV) emission from GRBs. Potentially relevant emission mechanisms will be discussed along with what we have learned from existing observations, most notably by Fermi, which has greatly contributed to our knowledge of GRB physics as well as in other areas. Fermi high-energy prompt GRB...
There is a small sample of long-duration gamma-ray bursts built on the intersection of two types of events: bursts associated with supernovae (GRB-SN) and bursts emitting high-energy photons (GeV-GRB). Being only few cases these GeV-GRB-SN can nevertheless shed some light on the emission mechanisms spanning the whole electromagnetic spectrum. We systematize the known events and analyze the new...
The Fermi LAT spectra of many bright gamma-ray bursts have a power law component that extends to several GeV. This power law component is distinct from the Band function present at lower energies (< 10 MeV), and it suggests the importance of inverse Compton scatterings at high energies.
With the advent of GRB observations at very high energies by Imaging Atmospheric Cherenkov Telescopes...
Gamma-ray Bursts (GRBs) have always been considered within the highest priority targets for all modern imaging atmospheric Cherenkov telescopes (IACTs). For a long time, the detection of such events in the very-high-energy band (VHE; E>100 GeV) posed a major challenge for IACTs from both the technical and the scientific point of view. On the other hand, it was well proven that the possibility...
Observation of high energy and very high emission from Gamma Ray Bursts (GRBs) is crucial to study the gigantic explosion and the underline processes. With a large field-of-view and almost full duty cycle, the Water Cherenkov Detector Array (WCDA), a sub-array of the Large High Altitude Air Shower Observatory (LHAASO), is appropriate to monitor the very high energy emission from unpredictable...
It has been established that Gamma-Ray Bursts (GRB) can produce Very High Energy radiation (E > 100 GeV), opening a new window through which to investigate particle acceleration and radiation properties in the most energetic domain. We expect that next-generation instruments, such as the Cherenkov Telescope Array (CTA), will mark a huge improvement in their observation. However, constraints...
