Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · 2507.05215

Testing the ubiquitous presence of very high energy emission in gamma-ray bursts with the MAGIC telescopes

S. Abe·J. Abhir·A. Abhishek·V. A. Acciari·A. Aguasca-Cabot·I. Agudo·T. Aniello·S. Ansoldi·L. A. Antonelli·A. Arbet Engels·C. Arcaro·T. T. H. Arnesen·K. Asano·A. Babic·C. Bakshi·U. Barres de Almeida·J. A. Barrio·L. Barrios-Jimenez·I. Batkovic·J. Baxter·J. Becerra Gonzalez·W. Bednarek·E. Bernardini·J. Bernete·A. Berti·J. Besenrieder·C. Bigongiari·A. Biland·O. Blanch·G. Bonnoli·Ž. Bošnjak·E. Bronzini·I. Burelli·A. Campoy-Ordaz·A. Carosi·R. Carosi·M. Carretero-Castrillo·A. J. Castro-Tirado·D. Cerasole·G. Ceribella·Y. Chai·A. Cifuentes·J. L. Contreras·J. Cortina·S. Covino·G. D'Amico·P. Da Vela·F. Dazzi·A. De Angelis·B. De Lotto·R. de Menezes·M. Delfino·J. Delgado·C. Delgado Mendez·F. Di Pierro·R. Di Tria·L. Di Venere·A. Dinesh·D. Dominis Prester·A. Donini·D. Dorner·M. Doro·L. Eisenberger·D. Elsaesser·J. Escudero·L. Fariña·A. Fattorini·L. Foffano·L. Font·S. Fröse·S. Fukami·Y. Fukazawa·R. J. García López·S. García Soto·M. Garczarczyk·S. Gasparyan·M. Gaug·J. G. Giesbrecht Paiva·N. Giglietto·F. Giordano·P. Gliwny·N. Godinovic·T. Gradetzke·R. Grau·D. Green·J. G. Green·P. Günther·D. Hadasch·A. Hahn·T. Hassan·L. Heckmann·J. Herrera Llorente·D. Hrupec·R. Imazawa·S. Inoue·D. Israyelyan·J. Jahanvi·I. Jiménez Martínez·J. Jiménez Quiles·J. Jormanainen
View original source ↗Read source document ↗Export metadata ↓

Abstract

Gamma-ray bursts (GRBs) are the most powerful transient objects in the Universe, and they are a primary target for the MAGIC Collaboration. Recognizing the challenges of observing these elusive objects with Imaging Atmospheric Cherenkov Telescopes (IACTs), we implemented a dedicated observational strategy that included an automated procedure for rapid re-pointing to transient sources. Since 2013, this automated procedure has enabled MAGIC to observe GRBs at a rate of approximately ten per year, which led to the successful detection of two GRBs at very high energies (VHE; E > 100 GeV). We present a comprehensive analysis of 42 non-detected GRBs (4 short GRBs) observed by MAGIC from 2013 to 2019. We derived upper limits (ULs) on the observed energy flux as well as on the intrinsic energy flux corrected for absorption by the extragalactic background light (EBL) from the MAGIC observations in selected energy and time intervals. We conducted a comprehensive study of their properties to investigate the reasons for these non-detections, including the possible peculiar properties of TeV-detected GRBs. We find that strong EBL absorption significantly hinders TeV detection for the majority of GRBs in our sample. For a subset of 6 GRBs with redshift z < 2, we compared the UL on the intrinsic flux in the VHE domain with the simultaneous X-ray flux, which is observed to be at the same level in the current population of TeV-detected GRBs. Based on these inferred MAGIC ULs, we conclude that a VHE component with a luminosity comparable to the simultaneously observed X-ray luminosity cannot be ruled out for this sample.

Explore related subjects

astro-ph.HE

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

S. Abe, J. Abhir, A. Abhishek, V. A. Acciari, A. Aguasca-Cabot, I. Agudo, T. Aniello, S. Ansoldi, L. A. Antonelli, A. Arbet Engels, C. Arcaro, T. T. H. Arnesen, K. Asano, A. Babic, C. Bakshi, U. Barres de Almeida, J. A. Barrio, L. Barrios-Jimenez, I. Batkovic, J. Baxter, J. Becerra Gonzalez, W. Bednarek, E. Bernardini, J. Bernete, A. Berti, J. Besenrieder, C. Bigongiari, A. Biland, O. Blanch, G. Bonnoli, Ž. Bošnjak, E. Bronzini, I. Burelli, A. Campoy-Ordaz, A. Carosi, R. Carosi, M. Carretero-Castrillo, A. J. Castro-Tirado, D. Cerasole, G. Ceribella, Y. Chai, A. Cifuentes, J. L. Contreras, J. Cortina, S. Covino, G. D'Amico, P. Da Vela, F. Dazzi, A. De Angelis, B. De Lotto, R. de Menezes, M. Delfino, J. Delgado, C. Delgado Mendez, F. Di Pierro, R. Di Tria, L. Di Venere, A. Dinesh, D. Dominis Prester, A. Donini, D. Dorner, M. Doro, L. Eisenberger, D. Elsaesser, J. Escudero, L. Fariña, A. Fattorini, L. Foffano, L. Font, S. Fröse, S. Fukami, Y. Fukazawa, R. J. García López, S. García Soto, M. Garczarczyk, S. Gasparyan, M. Gaug, J. G. Giesbrecht Paiva, N. Giglietto, F. Giordano, P. Gliwny, N. Godinovic, T. Gradetzke, R. Grau, D. Green, J. G. Green, P. Günther, D. Hadasch, A. Hahn, T. Hassan, L. Heckmann, J. Herrera Llorente, D. Hrupec, R. Imazawa, S. Inoue, D. Israyelyan, J. Jahanvi, I. Jiménez Martínez, J. Jiménez Quiles, J. Jormanainen. 2025-07-07. Testing the ubiquitous presence of very high energy emission in gamma-ray bursts with the MAGIC telescopes. https://doi.org/10.1051/0004-6361%2F202555468

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Deciphering the Physical Origin of GRB 240825A: A Long GRB Lacking a Bright Supernova

We present a comprehensive multiwavelength analysis of GRB 240825A, a bright gamma-ray burst (GRB) detected by Fermi and Swift, with a prompt duration ($T_{\rm 90}$ $\sim$ 4 sec in 50-300 keV in GBM) near the boundary separating short and long GRBs, prompting a detailed investigation into its classification and progenitor. We use classical prompt metrics (duration, minimum variability timescale (MVT), lag, and spectral hardness) and modern classification techniques (machine-learning (ML) based t-SNE, support vector machine, energy-hardness-duration, and $\varepsilon \equiv E_{γ,\mathrm{iso},52} / E_{p,z,2}^{5/3}$) and find most properties (prompt energetics, placement on the Amati relation, and spectral lag) of GRB 240825A consistent with a collapsar origin. However, extensive late-time optical and NIR follow-up with the 10.4m GTC and 8.4m binocular LBT telescopes reveals no bright supernova (like SN 1998bw) is detected down to stringent limits (e.g., $m_r > 25.0$ mag at 17.59 days), despite a redshift of $z = 0.659$ measured from GTC spectroscopy. Host galaxy SED modeling with Prospector indicates a massive, and star-forming galaxy-typical of collapsar GRB hosts, though with a large offset. We compare these findings with hybrid events like GRB 211211A, GRB 230307A, GRB 200826A, including SNe-GRBs, and conclude that GRB 240825A most likely originated from a massive star collapse, possibly with the associated SN heavily obscured or intrinsically faint. This study emphasizes the need for multiwavelength follow-up and a multi-layered classification to determine GRB progenitors.

astro-ph.HE↗
arXiv2026

The impact of flickering variability and magnetisation on the dynamics, stability and morphology of radio-loud AGN jets

The physics governing the morphology of radio-loud AGN jets is not fully understood. We investigate how magnetization, flickering jet power and their interplay affects the morphology of radio galaxies. We present a grid of relativistic magnetohydrodynamic simulations using the PLUTO code covering constant and variable jets with two levels of magnetisation. We find that the constant high magnetisation jets can lead to highly asymmetrical cocoon morphologies, whilst the variable high magnetisation jet can exhibit a broken morphology, caused by a discontinuous jet beam. Our work highlights the importance of magnetisation and variability on the stability and resulting morphology of radio-loud AGN jets, suggesting both are significant factors in addition to jet power or environment. Furthermore, we show that the interaction between magnetisation and variability can lead to the development of localised kink instabilities along the jet beam. Finally, we discuss the effects of hydrodynamic mixing in low magnetisation jets and the role of viewing angle dependence in comparisons between our simulations and observed sources. To facilitate this comparison we present a library of simulated radio images at different times in the simulations and from various viewing angles, which highlight a diverse set of complex morphologies.

astro-ph.HE↗
arXiv2026

Magnetic Eruption and Nucleosynthesis in GRνMHD Simulations of Spinning Neutron Star Mergers

We present three-dimensional general relativistic magnetohydrodynamics simulations of equal-mass binary neutron star mergers with varied neutron star spin configurations and second-moment neutrino transport, following the formation and early evolution of long-lived remnants. We compare a fiducial irrotational binary with binaries having spins that are aligned or antialigned with the orbital angular momentum, and examime how spin affects the merger dynamics, magnetic field evolution, outflows, and nucleosynthesis. Compared to the fiducial case, the aligned spin configuration releases more cold, neutron-rich tidal ejecta in the equatorial plane, which enables the development of a more tightly collimated polar outflow erupting from the remnant and inner accretion disk. Conversely, the case with spins antialigned with the orbit experiences a more violent collision at merger, disrupting magnetic amplification, loading the environment with debris, and impeding the propagation of magnetically driven winds. Strong neutrino reprocessing of the polar outflow in the irrotational and aligned spin cases produces $2.4\times 10^{-3}\,M_\odot$ of proton-rich ($Y_e \geq 0.49$) material, resulting in the synthesis of light r-process elements, whose subsequent decay potentially sends a unique electromagnetic signal from long-lived remnants. However, the outflows remain too dense and slow to be consistent with typical short gamma-ray bursts.

astro-ph.HE↗