Event

Gamma-ray bursts are the biggest explosions in our Universe since the Big Bang: In just a few seconds, they release as much energy as the Sun will radiate over its entire lifetime. Even though they occur in far-away galaxies, their emission dominates the high-energy astrophysical sky during their seconds-long duration. They come from the cataclysmic deaths of very massive stars or the mergers of two compact objects such as neutron stars and black holes. In both cases the energy is concentrated in an astrophysical jet moving at approximately the speed of light. In October 2022, a once-in-a-lifetime gamma-ray burst smashed records and was dubbed the ‘Brightest of All Time,’ or the BOAT. In fact, it was so bright that it oversaturated the most sensitive gamma-ray burst monitors, posing a challenge for data reconstruction and analysis. But why was it so bright? And how long do we have to wait until the next one?

Using the BOAT as an example, we will give an introduction about the fascinating phenomena called gamma-ray bursts. From their accidental discovery during the Cold War to our still surprisingly limited understanding of their nature. The talk will revisit the state-of-the-art of theoretical modelling/interpretations (how are jets launched? what produces the gamma rays?), as well as current detector techniques (how do we catch a gamma-ray photon on Earth or in space?). Naturally, we will also discuss what we really learn from prominent, outstanding events such as the BOAT -- and the questions that still give scientists headaches. **** Literature References/Further Reading ****

[R1] Vela 4 satellites https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=1967-040A​ [R2] First GRB publication Klebesadel et al 1973 https://articles.adsabs.harvard.edu/pdf/1973ApJ...182L..85​ [R3] Statistical test of isotropy on BATSE sample https://arxiv.org/abs/astro-ph/9509078 ​ [R4] First afterglow https://ui.adsabs.harvard.edu/abs/1997Natur.387..783C/abstract ​ [R5] First redshift measurement https://www.nature.com/articles/43132 ​ [R6] Gravitational waves NS-NS GW170817 and short GRB 170817A https://iopscience.iop.org/article/10.3847/2041-8213/aa920c/meta ​ [R7] Possible evolutions of a compact binary merger and assigned GW signals https://arxiv.org/abs/1212.2289​ [R8] A unified picture for compact binary mergers https://arxiv.org/abs/2309.00038 ​ [R9] Properties of Wolf-Rayet stars https://arxiv.org/abs/astro-ph/0610356​ [R10] Blandford-Znajek mechanism for jet launching, original paper https://academic.oup.com/mnras/article/179/3/433/962905 and short summary https://www.seramarkoff.com/2019/04/how-are-magnetised-jets-launched/ ​ [R11] GR-MHD simulation of NS-NS merger jet https://arxiv.org/abs/2205.01691 ​ [R12] GR-MHD simulation of collapsar jet https://arxiv.org/abs/2204.12501 ​ [R13] Fermi acceleration at astrophysical shocks confirmed by numerical simulations https://iopscience.iop.org/article/10.1086/590248 ​ [R14] Numerical simulations of acceleration in magnetic reconnection https://iopscience.iop.org/article/10.1088/2041-8205/783/1/L21 ​ [R15] Summary paper for current status of prompt phase GRB https://doi.org/10.3390/galaxies10020038 ​ [R16] Basic afterglow theory from a decelerating blastwave https://arxiv.org/abs/astro-ph/9712005 ​ [R17] Design example of optical telescope https://www.lsst.org/about/tel-site/optical_design​ [R18] Fermi GBM design https://ui.adsabs.harvard.edu/abs/2009ApJ...702..791M/abstract ​ [R19] Fermi LAT summary https://ui.adsabs.harvard.edu/abs/2022hxga.book..118R/abstract ​ [R20] LHAASO instrument and science https://arxiv.org/abs/1905.02773 ​ [R21] GCN of GRB 221009A https://gcn.gsfc.nasa.gov/other/221009A.gcn3 + TeVCat http://tevcat.uchicago.edu/?mode=1;id=364 ​ [R22] Fermi-GBM Pulse Pileup reconstruction https://ui.adsabs.harvard.edu/abs/2013NIMPA.717...21C/abstract​ [R23] The BOAT in context with other events https://iopscience.iop.org/article/10.3847/2041-8213/acc39c/meta​ [R24] Swift paper on the BOAT https://iopscience.iop.org/article/10.3847/2041-8213/acbcd1 ​ [R25] A structured jet explains the BOAT https://arxiv.org/abs/2302.07906 (open access version of science article) ​ [R26] LHAASO reports TeV emission from narrow jet https://arxiv.org/abs/2306.06372 (open access version of science article)​ [R27] LHAASO extra component at the highest energies https://www.science.org/doi/10.1126/sciadv.adj2778 ​ [R28] The BOAT high-energy emission explained by beyond the standard model physics https://arxiv.org/abs/2305.05145 ​

***** Image References ***** [IM1] 123RF​ [IM2]USAF​ [IM3] Bonnell 1995​ [IM4] https://en.m.wikipedia.org/wiki/File:Compton_Gamma_Ray_Observatory_grappeled_by_Atlantis_(S37-99-056).jpg​ [IM5] D. Perley, Wikimedia Commons https://en.m.wikipedia.org/wiki/File:GRB_BATSE_12lightcurves.png​ [IM6] https://www.esa.int/Science_Exploration/Space_Science/Gaia/Gaia_creates_richest_star_map_of_our_Galaxy_and_beyond​ [IM7] BATSE https://heasarc.gsfc.nasa.gov/docs/cgro/images/epo/gallery/grbs/index.html​ [IM8] E. Costa et al., Nature, Vol. 387, Issue 6635, pg. 783-785 (1997). https://ui.adsabs.harvard.edu/abs/1997Natur.387..783C/abstract ​ [IM9] https://heasarc.gsfc.nasa.gov/docs/sax/saxgof.html ​ [IM10] Neil Gehrels Swift Observatory​ [IM11] https://commons.wikimedia.org/wiki/File:Redshift.svg​ [IM12] https://commons.wikimedia.org/wiki/File:The_Blue_Marble_(remastered).jpg​ [IM13] https://en.wikipedia.org/wiki/File:NGC_4414_(NASA-med).jpg​ [IM14] Edo Berger (Harvard/CfA)​ [IM15] NASA's Goddard Space Flight Center​ [IM16] BATSE team​ [IM17] iStock​ [IM18] https://arxiv.org/abs/1212.2289​ [IM19] https://www.nasa.gov/image-article/mini-supernova-explosion-could-have-big-impact/​ [IM20] Ore Gottlieb https://oregottlieb.com/NSM_GRMHD.html ​ [IM21] Ore Gottlieb https://oregottlieb.com/collapsar.html ​ [IM22] NASA/CXC/Rutgers/J.Warren & J.Hughes et al ​ [IM23] NorthNorth West​ [IM24] https://www.stockio.com/free-clipart/cartoon-eyes​ [IM25] https://eljentechnology.com/products/plastic-scintillators​ [IM26] C. Meegan et al., ApJ, Vol. 702, Issue 1, pg. 791-804 (2009)​ [IM27] NASA, https://science.nasa.gov/toolkits/spacecraft-icons​ [IM28] W. B. Atwood et al., ApJ Vol. 697, pg. 1071 (2009)​ [IM29] NASA, https://commons.wikimedia.org/wiki/File:GLAST_on_the_payload_attach_fitting.jpg​ [IM30] NASA and Steven Ritz / UC Santa Cruz​ [IM31] J. Knapp​ [IM32] Armelle Jardin-Blicq, https://ui.adsabs.harvard.edu/abs/2019PhDT........47J/abstract​ [IM33] LHAASO​ [IM34] https://en.m.wikipedia.org/wiki/File:BlankMap-World.svg ​ [IM35] https://www.center.top/eng/attractions/202203/58434437.html ​ [IM36-IM38] Adam Goldstein, Fermi-GBM​ [IM39] V. Chaplin et al., NIM-A, Vol. 717, pg. 21-36 ​ [IM40] C. Meegan et al., ApJ, Vol. 702, Issue 1, pg. 791-804 (2009)​ [IM41 & IM43] Maia A. Williams et al 2023 ApJL 946 L24 ​ [IM42 & IM44] Eric Burns et al 2023 ApJL 946 L31​ [IM45] LHAASO collaboration Science 380 (2023) 6652​ [IM46] LHAASO collaboration Sci.Adv. 9 (2023) 46, adj2778