Gamma ra 1. Cavity Detection • Centaurus - broad, soft, hard (inc. source-filled) • Sanders et al. 2016. CADET. Allen et al. 2006 • unsharp masking / beta modelling / CADET (one or more • students will get kT, ne profiles -> E, Pjet 2. Supernova remnant • SN1006. Winkler et al. 2014 • CIAO -> fluximages (2003, 2012) • expansion rate using DS9 / astropy • narrow band images -> metal distribution 3. GRB properties • GRB230307, • data from GRBalpha, VZLUSAT2 • orientation, T90, HR • neutron star collision -> kilonova 4. Spectral fitting - thermal (cluster) • Centaurus, Sanders et al. 2006 • real Chandra data • estimate temperature (1T, 2T, 3T, gdem) & metallicity 5. Spectral fitting - thermal (XRISM) • Perseus, XRISM spectrum, SPEX / Xspec • velocity broadening, redshift, temperature, metallicity 6. Spectral fitting - deprojection (giant elliptical) • NGC4649, real Chandra data, • deproject (Sherpa) • kT, ne, P, K, M( explosions must involve a compact object • the consensus at the end of 1980s was that GRBs originate in our Galaxy The Compton Gamma-Ray Observatory Burst and Transient Source Experiment (BATSE) NASA's Compton Gamma Ray Observatory EGRET 2704 BATSE Gamma-Ray Bursts +90 Gamma Ray Bursts distributed isotropically Trigger 105 Seconds Trigger 1425 Seconds Trigger 2067 Seconds Trigger 2571 ■\::r. 3CG 2SC o 100 Trigger 143 Trigger 1406 10 800 § 600 ■2 400 o 200 Seconds Trigger 1606 ISO Seconds Trigger 2151 Seconds Trigger 2812 i DO Seconds Trigger 1974 Seconds Trigger 2514 Seconds Trigger 3152 0.!> Seconds Seconds Seconds Large diversity of bursts Two flavors of GRBs • short GRBs with a duration of a fraction of a second • long GRBs lasting ~ 10s of seconds • dividing line Tgo~3s (T90 contains 90% of the counts) -2.0 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0 Observed Duration: Log(TgQ [s]) Two flavors of GRBs Hardness ratio = count rate (hard) / coun trate (soft) hard: 100-300 keV soft: 50-100 keV 1000 10.0 Long/soft Short/hard 0) 1.0 n—11111 0,1 I.......i 0.1 i i i i i 11 i i—i—i i i i i i ..... -i-1—i i i _i_.....■' 1.0 10.0 Duration (s) 100.0 slope 3/2 Distribution is isotropic, but inhomogeneous. Homogeneous out to large distance, then the number density drops. Similar to the distribution of galaxies... still Galactic halo not ruled out logF ' v u Eiso = 4nd2f = 2x1040 erg for d= 15 kpc Foe c/-2 =2x1041 erg for 6=50 kpc N ^ p-3/2 = 2x1051 erg for 6=5 Gpc Solving the mystery SAX [VI ACCOMODATION C.ONCFVTR-ATORS WIDE FIELD CAMERAS UPPir.K If LOOK SHEAR PANEL COKE The Italian-Dutch BeppoSax satellite with its Wide Field Cameras was the first to find a GRB X-ray afterglow and determine its position on the sky GRBs are of extragalactic origin! Association with "Hypernovae" 3000 4000 5000 6000 7000 Rest Wavelength (Á) 6 days after the GRB a supernova became visible as a bump in the optical light-curve. This established the connection of long GRBs and supernovae. The compactness problem E ~ ATlcP-f (total energy involved; fluence f\s the flux s-1 ) D< C At - 300 km (size of the source) fly ~ 47ZCpf/(EyD3) (number density of photons with energy Ey) Tie — feVly (fraction of photons producing electron positron pairs 2 x 0.511 MeV) J V5Gpc/ Vl0"6ergcm-2/ V Ey J \ At if true then large number of pairs produced resulting in thermal spectra - contrary to observations r, cos 0 r, cos 0 to observer • the source can be larger by a factor of y2 (Lorenz factor y2=1/(1-vz/c2)) • ft,obs = fi.em + (d - riCOS0)/c; fe,obs = fc,em + (d - r2COS0)/c • Atobs = feobs - h ,obs = Atem(1-(3C0S9) - y2 • photons blue shifted, EY,0bs = EY;em y, in reality only a small fraction of photons is energetic enough to produce electron-positron pairs • to circumvent the compactness problem, relativistic motions with Lorenz factors of hundreds toward the observer required Collimated outflows e, 4tT AQ = 2 • / / sin# dO d

9j, the light curve will drop faster than before at all wavelengths Achromatic break Typical 9j are around 4 degrees time [doys since GRB 990510] ÍO49 ÍO50 1061 1052 1053 1054 Energy (erg) The afterglows of short GRBs Coded Aperture Mask / Radiator Graded-Z Shield Optical Bench Module Control Box BAT Detector Array Power Supply Box The detection of the first afterglow of a short GRB had to wait until 2005, the SWIFT satellite The involved energies are smaller by ~3 orders of magnitude Short GRBs have systematically lower redshifts They occur in all types of galaxies, also galaxies with no star formation.This points to older stellar population Two flavors of GRBs long GRBs only in blue star-forming galaxies - young stars short GRB in non-star-forming elliptical galaxies - old stars The fireball model hidden engine produced in ^107cm ^1013cm external shocks ^1018cm • Central engine, 1051 erg in ro = 100 km, E/MbaryonsC2 > 100 (/Vfbaryons=E/yc2 = 6x10-6 MSun(f/705i erg) (100/y)) • expansion to ultra-relativistic velocities (requires low baryon loading) • optical depth drops below 1, thermal preburst • production of gamma rays via internal shocks (outflow not completely homogeneous, contains portions with different Lorenz factors that collide with each other) Short GRB are due to NS-NS or NS-BH merger • several times 1053erg of binding energy released • 105 mergers per galaxy (observed burst rate 107) • Tdyn.ns = 0.4 ms(1014g cm-3/p)i/2 • T=2n/o)K,isco~ 1ms (MBH/3Msun) • because of long in-spiral of the compact binary, mergers occur late in the evolution of the Universe Crashing neutron stars can make gamma-ray burst jets Simulation begins 7.4 milliseconds 13.8 milliseconds 15.3 milliseconds 21.2 milliseconds 26.5 milliseconds Credit: NASA/AEI/ZIB/M. Koppitz and L. Rezzolla Soft-Gamma Ray Repeaters 0 100 200 300 Time (seconds) strongest burst with E=2x1046 erg (1043 ergs s~1) in December 2004 from SGR 1806-20 hard spike with a rise time of -1 ms, the rest released in a softer tail with pulsations dye to neutron star rotation Magnetars • if the rotation period at birth is shorter than the convective overturn time,rConv ~ 10 ms magnetic field can be amplified by dynamo action to 1014—1015 Gauss (convection because of entropy and lepton-number gradient due to neutrino radiation) • field strengths are larger than the quantum-critical magnetic field where Larmor radius rL=vmec/eB < \dB=h/mev; Bqc=4.4x1013 G (other effects: photons propagate speeds depending on polarisation, atoms in a magnetar atmosphere have needle like shapes • P = 5-8 s Pdot ~ 7x10"11 s S"1 (they spin down in -300 years) Soft-Gamma Ray Repeaters Emag ~ i/mag V ~ £2/8n 4/3 TtFP ~ 1048erg magnetar quake releases few percent of the magnetic energy reservoir create a fireball and a trapped (evaporating) fireball First two papers in Astronomy and Astrophysics A&A677,L2 (2023) https ://doi. org/10.1051 /0004-6361 /202346128 ©The Authors 2023 /^stronomy Astrophysics A&A 677, A40 (2023) https://doi.org/10.1051/0004-6361/202346182 ©The Authors 2023 Astronomy Astrophysics Letter to the Editor The peak flux of GRB 221009A measured with GRBAIpha Jakub Řípa' , Hiromitsu Takahashi2, Yasushi Fukazawa2, Norbert Werner' , Filip Münz', András Pál3, Masanori Ohno2, Marianna Dafčíková', László Mészáros3, Balázs Csák3, Nikola Husáriková', Martin Kolář', Gábor Galgóczi4,5, Jean-Paul Breuer', Filip Hroch', Ján Hudec6, Jakub Kapuš6, Marcel Frajt6, Maksim Rezenov6, Robert Laszlo7, Martin Koleda7, Miroslav Smelko8,9, Peter Hanák9, Pavol Lipovský9, Tomáš Urbanec'0, Miroslav Kasal'0, Aleš Povalač'0, Yuusuke Uchida", Helen Poon2, Hiroto Matake2, Kazuhiro Nakazawa'2, Nagomi Uchida'3, Tamás Bozóki'4, Gergely Dálya'5, Teruaki Enoto'6, Zsolt Frei4, Gergely Friss4, Yuto Ichinohe'7 Kornel Kapáš18,19,5, László L. Kiss3, Tsunefumi Mizuno2, Hirokazu Odaka20, Jánoš Takátsy4,5, Martin Topinka21, and Kento Torigoe2 (Affiliations can be found after ihe references) Received 12 February 2023 / Accepted 14 March 2023 is detected by a multitude of ABSTRACT Context On 2022 October 9 the brightest gamma-ray burst (GRB) ever observed lit up the high-ene instruments, attracting the close attention of the GRB community, and saturated many detectors. Aims. GRBAIpha, a n a no-satellite with a form factor of a 1U CubeSat, detected this extraordinarily bright long-duration GRB, GRB 221O09A, without saturation but affected by pile-up. We present light curves of the prompt emission in 13 energy bands, from SOkeV to 950keV, and performed a spectra] analysis to calculate the peak flux and peak isotropic-equivalen Methods. Since the satellite's attitude information is not available for the time of this GRB, more than 200 incident d: order to find the median luminosity and its systematic uncertainty. Resets. We find that the peak flux in theSO-SOOkeV range (observer frame) was F*h = 1300+™ phcrn"2 s"', or F\^ = 5.7^-and the fluence in the same energy range of the first GRB episode, which lasted 300s and was observable by GRBAIpha, 10~2ergcm~2, or SKI = 4.9+°!| x 10"2 ergcrn"2 for the extrapolated range of 0.9-8690keV. We infer the isotropic-equival of the first GRB episode to be = 2.S+_°!| x lO^erg in the l-10000keV band (rest frame at i = 0.15). The peak luminosity in the 92-920keV range (rest frame) was Z?^ = 3.7*2^ x 1052 ergs"1, and the bolometric peak isotropic-equiva j-p.boi = s 4+25 x ioi2ergs-' (4 s scale) in the 1-10000keV range (rest frame). The peak emitied energy is E' = Ev( e probed in 20± 470keV. Our individual: GRB 221O09A measurement of is consisteni GRBAIpha at the peak time, the tr Keywords, gamma-ray bui 1. Introduction On 2022 October 9 at 13:16:59.988 LIT, the Fermi Gamma-ray Burst Monitor (GBM) detected the exceptionally bright long gamma-ray burst (GRB) GRB 221009A (Veres et al. 2022; Lesageetal. 2022, 2023). The burst was also observed by the Fermi Large Area Telescope (LAT) up to the energy of 100GeV (Pilleraet al. 2022). Potentially remarkable detections of over 5000 very high-energy photons with energies up to ISTeV were reported by the Large High Altitude Air Shower Observatory (LHAASO; Huang etal. 2022), and a possible 251 TeV photon was reported by Carpet-2 (Dzhappuev et al ), triggering the interest of the broader physics The burst was localised by the Neil Gehreis Swift Observatory's Burst Alert Telescope (Dichiara et al. 2022) and followed up by the Very Large Telescope (VLT) X-shooter instrument (de Ugarte Postigo et al. 2022; Malesani et al. 2023), which determined that it occurred at a redshift of 0.151 and belongs to very near long GRBs (Oates 2023). It was also detected by a multitude of other instruments: AGILE/GRID (Piano et al evoluti i of this GRB and the 2022), AGILE/MCAL (Ursi et al. 2022), BepiColombo/MGNS (Kozyrev et al. 2022), Insight-HXMT and SATech-01/GECAM-C (HEBS; An etal. 2023), INTEGRAL/SPI-ACS (Götz etal 2022), Konus-WIND & SRG/ART-XC (Frederiks et al. 2023), MAXI and NICER (Williams et al. 2023), Solar Orbiter/STIX (Xiao etal. 2022), STPSat-6/SIRI-2 (Mitchell et al. 2022), and XMM-Newton (Tien go et al. 2023). This brightest ever recorded GRB (Bums et al. 2023; O'Connor et al. 2023) saturated many of the GRB detectors in orbit, hampering the efforts to determine its peak luminosity. In this Letter, we present the peak flux and peak isotropic-equivalent luminosity of this extraordinary transient as measured by the GRBAIpha nano-satellite. 2. GRBAIpha GRBAIpha (Paletal. 2020) is a 1U CubeSat carrying a GRB detector as a technology demonstration for an envisioned future CubeSat constellation (Wemer et al. 2018; M6szaros et al. 2022). It was launched on 2021 March 22 into a Sun-synchronous GRBAIpha: The smallest astrophysical space observatory I. Detector design, system description, and satellite operations András Pál' , Masanori Ohno2, László Mészáros', Norbert Werner3, Jakub Řípa3, Balázs Csák', Marianna Dafčíková3, Marcel Frajt4, Yasushi Fukazawa2, Peter Hanák5, Ján Hudec4, Nikola Husáriková3, Jakub Kapuš4, Miroslav Kasal6, Martin Kolář3, Martin Koleda7, Robert Laszlo7, Pavol Lipovský5, Tsunefumi Mizuno2, Filip Münz3, Kazuhiro Nakazawa8, Maksim Rezenov4, Miroslav Smelko9, Hiromitsu Takahashi2, Martin Topinka10, Tomáš Urbanec6, Jean-Paul Breuer3, Tamás Bozóki", Gergely Dálya12 Teruaki Enoto13, Zsolt Frei14, Gergely Friss14, Gábor Galgóczi14,'5, Filip Hroch3, Yuto Ichinohels, Komél Kapáš17,l8,15, László L. Kiss', Hiroto Matake2, Hirokazu Odaka19, Helen Poon2, Aleš Povalač6, Jánoš Takátsyl4,15, Kento Torigoe2, Nagomi Uchida20, and Yuusuke Uchida21 1 Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly-Thege M. lít 15-17, 1121 Budapest, Hungary e-mail: apal@szofi.net 2 Hiroshima University, School of Science, 1-3-1 Kagamiyama, Higashi-Hiroshima, Japan ! Department of Theoretical Physics and Astrophysics, Faculty of Science, Masaryk University, Kotlářská 257/2, Brno oil 37, Czech Republic 4 Spacemanic Ltd, Jablonec 110, 900 So Jablonec, Slovakia 5 Faculty of Aeronautics, Technical University of Košice, Rampová 1731/7, 040 01 Košice, Slovakia 6 Department of Radio Electronics, Faculty of Electrical Engineering and Communication, Brno University of Technology, Technická 3058/10, SIS 00 Brno-Královo Pole, Czech Republic 7 Needronix Ltd, Geologická 1, 821 OS Bratislava, Slovakia 6 Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan ' ED1S vvd., Rampová 7, 041 21 Košice, Slovakia 10 1NAF lstituto di Astrofisica Spaziale e Fisica Cosmica, via Bassini 15, 20133 Milano, Italy 11 Institute of Earth Physics and Space Science (EPSS), Csatkai E. u. 6-8, 9400 Sopron, Hungary 12 Department of Physics and Astronomy, Universiteit Gent, Proeftuinstraat 86, 9000 Gent, Belgium l! School of Science, Kyoto University, 1 Matsugasakihashigami-cho, Sakyo-ku, Kyoto, Japan 14 Eotvos Loránd University, Institute for Physics, Pázmány Peter stny. 1/A, Budapest, Hungary 15 Wigner Research Centre for Physics, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary 16 Department of Physics, Rikkyo University, 3-34-1 Nishi-lkebukuro, Toshima-ku, Tokyo, Japan 17 Department of Theoretical Physics, Institute of Physics, Budapest University of Technology and Economic, Mflegyetem ikp. 3, 1111 Budapest, Hungary 16 MTA-BME Quantum Dynamics and Correlations Research Group, Budapest University of Technology and Economics, Mflegyetem ikp. 3, 1111 Budapest, Hungary " Department of Earth and Space Science, Osaka University, 1-1 Machikaneyamacho, Toyonaka, Osaka, Japan 20 Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, 21 Tokyo University of Science, 2641 Yamazaki, Nöda, Chiba, Japan Received 18 February 2023 / Accepted 27 March 2023 Aims. Sim n 22 March 2021, the lU-sized CubeSat GRBAIpha operates and collects scientifii it the smallest astrophysical space observatory to date. GRBAIpha is an in-ottit demi standard 1U volume. P anity with ai L2,p 1 of burst (GRB) detector adds significant value t event of GRB 221009A. Methods. The GRB detector is a 75 x 75 x 5 mm Csl(Tl) scintillate detectors, multi-pixel photon counters by Hamamatsu, driven by twe from sunlight and protect the SiPM detectors from particle radiatior aluminium casing, and a lead-alloy shielding on one edge of the as; the energy range of 70-890 keV with an energy resolution of -30% Results. Here, we summarize the system design of the GRBAIpha t detector, some aspects of the platform, and the curn rage the ci detectors - space vehicles: demonstrated in a companion paper, GRBAIpha of bright GRBs, including the recent outstanding r wrapped in a reflective foil (ESR) read out by an array of SiPM separate redundant units. To further protect the scintillator block we applied a multi-layer structure of Tedlar wrapping, anodized ?mbly. The setup allows observations of gamma radiation within :s and software components of the :s with GRBAIpha and GRBAIpha mentioned along big famous observatories The Astrophysics Journal Letters, 942:L3Q (5pp), 2023 January 10 imp,: dei.ori: IIJ.!N47 :!14]-K2U 2. OBSERVATIONS CRB 221009A was identified by a large number of space-based "i-ray observatories. These ii (Veres et al. 2022), Fermi-LAT (Bissaldi et al. 2022), AGILE/MCAL (Ursi et al. 2022), AGILE, 2022), INTEGRAL (Götz et al. 2022), Konus- Wind (Frederiks et al. 2022) /nsijAi-HMXT (Tan c e/SIRI-2 (Mitchell el al. 2022), SATech-01/GECAM-C HEBS (Liu et al. 2022), SflG/ART-XC (1 Solar Orbiter/STIX (Xiao et al. 2022), and GRBalpha (Ripa et al. 2022). The initial brightness wan sufficiently extreme (and also considering its location on the sky in I he |>f......if tlie Mill- proposed !o be a new Calaelie transient lather limn a 800 ct/s) and moderately bright in the optical (unfiltered finding chart, white = 16.63 ± 0.14 mag). The optical detection was somewhat remarkable as the transient lies in the Galactic plane and extinction along the line-of-sight is very high, S(b-V) = 1-32 m&g/Av = 4.1 mag (Schlafly & Finkbeiner 2011, henceforth SF11). It was furthermore reported that the source was also detected over ten minutes earlier by the Gas-Slit Camera (GSC) of the MAXI X-ray detector onboard the International Space Station (ISS, Negoro et al. 2022; Kobayashi et al. 2022; Williams et al. 2023). Overall, this is in agreement with a new Galactic transient. About 6.5 hours after the Swift trigger, it was reported by Kennea et al. (2022a) that this source may be a GRB, GRB 221009A, as both the Gamma-Ray Burst Monitor (GBM, Mccgan et al. 2009) and the Large Area Telescope (LAT, Atwood et al. 2009) of the Fermi ob- SPI/ACS (Götz et al. 2022) analysis finds 1.3X10"2 erg/cm2, Fermi GBM finds (2.912 ± 0.001)xl0"2 erg/cm2 and peak flux 2385 ± 3 ph s-1 cm-2, Konus-Wind report 5.2xl0"2 erg/cm2 (Frederiks et al. 2022), and Kann ck Agui Fernandez (2022) estimate ^ 9 xlO-2 erg/cm2. Even these preliminary estimates show GRB 221009A exceeded GRB 130427A in fluence by a factor of at least 10. Several smaller orbital detectors were not saturated, stemming from size, environment, or off-axis detection, such as detectors on Insight (the Low-Energy (LE) telescope and the Particle Monitors, Go et al. 2022), SATech-01/GECAM-C HEBS (Liu et al. 2022), GRBAIpha (Ripa et al. 2022), STPSat-6/SIRI-2 (Mitchell et al. 2022), and SRG/AKI-XC (Lapshov et al. 2022). Optical spectroscopy of the transient showed it to indeed be a GRB afterglow, with a redshift z = 0.151 measured both in absorption and emission (de Ugarte Postigo et al. 2022; Castro-Tirado et al. 2022; Izzo et al. 2022, Malesani et al., in prep.), making it even closer than GRB 030329. Such an event is ultra-rare, e.g., Atteia (2022) estimate it to occur only once every half-millenium (sec also Williams et al. 2023, Burns et al., in prep.). Deciphering the ~18 TeV Photons from GRB 221009A imentode Fisiea ApliiMiNi. frnlm Ji' I in csiiajciin > itc h .lad ins Avjn/iidn, ilcl [FN. L'mdail Mcridii. A i1 7.1. (\much v.. Mania. YiwaLan 97310, Mexico ' l)qiiirlnu.'ri[ Dl' \'h\:i^ iiml Aslrnmmiy. falifdmia SlalL- i jTinursily. I 251} Hdlrlm\i:r Houlihan). Ijirij: Htadi, CA 'M)N4tl. USA Received 2022 November X; revised 2022 December i: accepted 2022 December 9: published 2023 January 11 Abstract On 2022 October 9, an extremely powerful gamma-ray burst, GRB 221009A, was detected by several instruments. Despite being obstructed by the Milky Way galaxy, its afterglow outburst outshone all other GRBs seen before. LHAASO detected several thousand very high energy photons extending up to 18 TeV. Detection of such energetic photons is unexpected due to the large opacity of the universe. It is possible that in the afterglow epoch, the intrinsic very high energy photon flux from the source might have increased manifolds, which could compensate for the attenuation by pah production with the extragalactic background light. We propose such a scenario and show that very high energy photons can be observed on the Earth from the interaction of very high energy protons with the seed synchrotron photons in the external forward shock region of the GRB jet. Unified Astronomy Thesaurus concepts: Gamma-ray bursts (629); Particle astrophysics (96) 1. INTRODUCTION Cosmological gamma-ray bursts (GRBs) are thought to be produced by , events: mergers of binary compact objects, such as two neutron stars or produce short, < 2 s, so called Type I GRBs: the core collapse of massive sti see, e.g., Zhang et al. (2009) for more information on the Type I/II classifi The measured GRB isotropic-equivalent energy release £is„ and isotropic with the most intense GRBs reaching close to E-lso ~ 1055 erg and L\so as h of Konus- WIND and Fermi-GBM samples of GRBs with known rcdshifts has a cutoff at Eiso ~ 1-3 x 1054 erg (Atteia et al. 2017; Tsvetkova et al. 21 extremely energetic GRBs. Bright nearby gamma-ray bursts provide a uniq physics, prompt emission and afterglow emission mechanisms, as well as C such bursts have been observed. On 2022 October 9 at T0 =13:17:00 UTC an extremely intense GRB 22 missions: Fermi (GBM and LAT; Veres et al. 2022; Lcsagc et al. 2022; Biss Wind (Svinkin et al. 2022; Frederiks et al. 2022), AGILE (MCAL and G INTEGRAL (SPI-ACS; Gotz et al. 2022), Insigkt-UXMT (Tan et al. 2025 Spektr-RG (ART-XC; Lapshov et al. 2022), GRBAIpha (Ripa et al. 2022) C (Liu et al. 2022), and BepiColombo (MGNS; Kozyrev et al. 2022). The initial analysis of the burst showed that the prompt emission was so intense that it saturated almost all instruments. (Lapshov et al. 2022). Solar Orhiter/STIX (Xiao et al. 2022), and GRBalpha (Ripa et al. 2022). However, the event was first reported by a Swift detection of the afterglow over 50 minutes later (Dichiara et al. 2022b). The location of the burst within the Galactic plane (f = 52.96°, b = 4.32"), combined with its brightness, led to confusion over the nature of the outburst: initially it was suspected to be due to a new Galactic X-ray transient (Dichiara et al. 2fJ22bja), but its subsequent behaviour appeared more like that of an extragalactic GRB (Kennea et al. 2022). Despite high foreground extinction (Section 3.2), an op-ii.nl afterglow was seen by various telescopes (e.g. Dichiara et al. 2022b; Lipunov et al. 2022; Fulton et al. 2023 and many more). The counterpart was localised at coordinates (J2000): RA = 19l,13m03;500792(2), dec = 19°46,24'/22891(7) by the VLBA at 15.2 GHz (Atri et al. 2022). Detection with several high energy instruments have also been reported, including GcV emission with Fermi-LAT (potentially up to 400 GeV; Xia et al. 2022), TeV emission extending to 18 TeV from LHAASO (Huang et al. 2022), and even a suggestion of a possible association with a 250 TeV photon (Dzhappuev et al. 2022). (de Ugarte Postigo et al. 2023, ir nally, we have applied a telluric correction using mod mated using the line-by-line radial ivc transfer model (LI Clough et al. 1992) and atmospheric properties, such as ity, temperature, pressure and zenith angle, which are s the header of each exposure. The observations revealed a very bright trace in the infrared, strongly attenuated towards the blue end by i Galactic extinction. Figure I shows the overall shape of t trum and zoom-in panels highlighting specific features. We subsequently obtained further X-shootcr obscrvi follow the afterglow evolution. These are discussed in ( de Ugarte Posdgo et al. (2023. in preparation). Among spectra, here wc only exploit the 4 x 600 s spectrum tal mid time 2022 Oct 20 00:19:38 UT, which provides the tection of the emission features (Fig. 1 and Sec. 3.3). The results reported in this paper supersede our nary analysis (de Ugarte Postigo et al. 2022; Izzo et al Our spectroscopic measurement was subsequently confi Castro-Tirado et al. (2022). ground light (EBL; (4,5)). 1. Introduction On 2022 October 9, at TO - 13:16:59.000 UT (Veres et al. 2022), a long-duration gamma-ray burst (GRB) identified as GRB 221009A (also known as Swift J1913.1+1946) was detected in the direction of the constellation Sagitta by the Gamma-ray Burst Monitor (GBM; Meegan et al. 2009) on board the Fermi Gamma-ray Space Telescope. The prompt emission was also detected by several other space observatories, such as the Fermi Large Area Telescope (LAT), Swift (Dichiara cl al. 2022; Krimm et al. 2022), AGILE (Piano et al. 2022; Ursi et al. 2022), INTEGRAL (Gotz et al. 2022), Solar Orbiter (Xiao et al. 2022), SRG (Lapshov et al. 2022), Konus (Frederiks et al. 2022), GRBAIpha (Ripa et al. 2022), and STPSat-6 (Mitchell et al. 2022). The GRB 2210O9A is located at the coordinate R.A. = 288.282 and dec!. = 19.495 (Pillera ct al. 2022). Fcrmi-LAT detected the most energetic photon of energy, 99.3 GeV (at tg + 240 s). It is the highest-energy photon ever detected by Fermi-LAT from a GRB in the prompt phase (Bissaldi et al. 2022; Pillera et al. 2022). The afterglow s also observed at different wavelengths (Das & detector observed more than 5000 very high energy (VHE) photons within T0 + 2000 s in the 500GeV-18 TeV energy range, making them the mosl energetic photons ever observed from a GRB (Huang et al. 2022), Surprisingly, the ground-based Cherenkov detector Carpet-2 at Baksan Neutrino Observatory reported the detection of what is undoubtedly a very rare air shower originating from a 251 TeV photon 4536 s after the GBM trigger from the direction of GRB 22I009A (Dzhappuev et al. 2022). Observations of these unusually VHE gamma rays by LHAASO and Carpet-2 from GRB 221009A are incomprehensible and led to speculation about nonstandard physics explanations of these observed events. However, there is a caveat concerning the observation of the 251 TeV gamma ray. The angular resolution of Carpet-2 is several degrees, and the two previously reported Galactic VHE sources, 3HWC 11928+178 and LHASSO 11929+1745, are located close to the position of GRB 221009A (Fraija & Gonzalez 2022). It remains uncertain whether the observed 251 TeV photon is from GRB 22I009A or either of these Galactic sources. Nevertheless, the temporal and spatial coincidence of this event 10-7 — 10-4 erg cm-2 (7) and spectra up to the MeV or, less frequently, GeV range (6). On October 10, 2022 at 13:16:59 UT (hereafter referred to as T0), the Gamma-ray Burst Monitor (GBM) aboard Fermi (7, 8), among many other high-energy satellites (INTEGRAL, Konus-Wind, AGILE, SRG, GRBAIpha, HEBS; (9-13)), detected an unprecedented, extremely bright burst lasting hundreds of seconds. This burst, dubbed GRB 221009A, is the brightest GRB ever detected in nearly 55 years of operating gamma-ray observatories, with an observed fluence of « 5 x 10~2 erg cm"2 in the 20 keV — 10 MeV band, more than an order of magnitude brighter than GRB 840304 and GRB 130427A (14), the previous record holders (Fig. 1). Its high-energy radiation was so intense that it disturbed Earth's ionosphere (15,16). GRB 230307Athe second brightest burst ever! —i-1-1-1-1-1-1-1— Bond 1: ~70 ^ E (keV) < ~110 Bond 2: ~1 10 § E (keV) < ~370 Bond 3: ~70 ^ E (keV) < ~110 + ~1 10 § E (keV) < ~370 ■ i i i-r- i i 8000 6000 4000 2000 0 0 + ~370 k B (keV) < ~630 + ~630 S E (keV) < ~890 20 40 60 80 Time (s) since 2023-03-07 15:43:18.377768 UTC 100 QUANTUM GRAVITY EXPERIMENT __L_ tf^brentz Invariance Violation (LIV): no further Lorentz contraction ii) Space has the structure of a crystal lattice iii) Existence of a dispersion law for photons in vacuo By Andrea Sanna QUANTUM GRAVITY EXPERIMEN THE ENERGY AND REDSHIFT DELAY DEPENDENCE High z -AAAA* Low z AAA A^. Time lags caused by Quantum Gravity effects: |Ephot(Band ll)-Ephot(Band I)| •V? DTRAv(ZGRB) Time lags caused by prompt emission mechanism: • complex dependence from Ephot(Band II) and Ephot(Band I) • independent of DTRAV(zGRB) By Andrea Sanna