GeV emission from a compact binary merger

An energetic γ -ray burst (GRB), GRB 211211A, was observed on 2021 December 11 by the Neil Gehrels Swift Observatory. Despite its long duration, typically associated with bursts produced by the collapse of massive stars, the discovery of an optical-infrared kilonova and a quasi-periodic oscillation during a gamma-ray precursor points to a compact ( ∼ 1 billion light-years) burst will significantly impact our knowledge of GRB progenitors and the physical processes that lead to electromagnetic emission in compact binary mergers. Here, we report the discovery of a significant ( > 5 σ ) transient-like emission in the high-energy γ -rays (HE; E > 0 . 1 GeV) observed by Fermi /LAT starting at 10 3 s after the burst. After an initial phase with a roughly constant flux ( ∼ 5 × 10 − 10 erg s − 1 cm − 2 ) lasting ∼ 2 × 10 4 s, the flux started decreasing and soon went undetected. The multi-wavelength ‘afterglow’ emission observed at such late times is usually in good agreement with synchrotron emission from a relativistic shock wave that arises as the GRB jet decelerates in the interstellar medium. However, our detailed modelling of a rich dataset comprising public and dedicated multi-wavelength observations demonstrates that GeV emission from GRB 211211A is in excess with respect to the expectation of this scenario. We explore the possibility that the GeV excess is inverse Compton emission due to the interaction of a long-lived, low-power jet with an external source of photons. We discover that the kilonova emission can provide the necessary seed photons for GeV emission in binary neutron star mergers.

[1]  Y. Li,et al.  A peculiar, long-duration gamma-ray burst from a neutron star-white dwarf merger , 2022 .

[2]  D. A. Kann,et al.  A kilonova following a long-duration gamma-ray burst at 350 Mpc , 2022, Nature.

[3]  A. Moiseev,et al.  Incremental Fermi Large Area Telescope Fourth Source Catalog , 2022, The Astrophysical Journal Supplement Series.

[4]  O. Salafia,et al.  Multiwavelength View of the Close-by GRB 190829A Sheds Light on Gamma-Ray Burst Physics , 2021, The Astrophysical Journal Letters.

[5]  I. Cognard,et al.  Fermi Large Area Telescope Performance after 10 Years of Operation , 2021, The Astrophysical Journal Supplement Series.

[6]  P. M'esz'aros,et al.  External Inverse-Compton Emission from Low-luminosity Gamma-Ray Bursts: Application to GRB 190829A , 2020, The Astrophysical Journal.

[7]  B. Giacomazzo,et al.  Accretion-to-jet energy conversion efficiency in GW170817 , 2020, Astronomy & Astrophysics.

[8]  Y. Yatsu,et al.  GRB 201223A: MITSuME Akeno optical observation , 2020 .

[9]  A. Moskvitin,et al.  GRB 201015A: SAO RAS optical observations , 2020 .

[10]  R. Ciolfi,et al.  Magnetically Driven Baryon Winds from Binary Neutron Star Merger Remnants and the Blue Kilonova of 2017 August , 2020, The Astrophysical Journal.

[11]  Hao Zhang,et al.  Inverse Compton signatures of gamma-ray burst afterglows , 2019, Monthly Notices of the Royal Astronomical Society.

[12]  Y. N. Liu,et al.  Multi-messenger Observations of a Binary Neutron Star Merger , 2019, Proceedings of Multifrequency Behaviour of High Energy Cosmic Sources - XIII — PoS(MULTIF2019).

[13]  F. Schinzel,et al.  Fermi Large Area Telescope Fourth Source Catalog , 2019, The Astrophysical Journal Supplement Series.

[14]  N. Masetti,et al.  A comparison between short GRB afterglows and kilonova AT2017gfo: shedding light on kilonovae properties , 2019, Monthly Notices of the Royal Astronomical Society.

[15]  P. M'esz'aros,et al.  Upscattered Cocoon Emission in Short Gamma-Ray Bursts as High-energy Gamma-Ray Counterparts to Gravitational Waves , 2019, The Astrophysical Journal.

[16]  Sebastiano Bernuzzi,et al.  Spiral-wave Wind for the Blue Kilonova , 2019, The Astrophysical Journal.

[17]  D. Costantin,et al.  A Decade of Gamma-Ray Bursts Observed by Fermi-LAT: The Second GRB Catalog , 2019, The Astrophysical Journal.

[18]  A. Lien,et al.  The afterglow and kilonova of the short GRB 160821B , 2019, Monthly Notices of the Royal Astronomical Society.

[19]  S. Covino,et al.  A kilonova associated with GRB 070809 , 2019, Nature Astronomy.

[20]  Chris L. Fryer,et al.  A luminosity distribution for kilonovae based on short gamma-ray burst afterglows , 2018, Monthly Notices of the Royal Astronomical Society.

[21]  L. Roberts,et al.  Binary Neutron Star Mergers: Mass Ejection, Electromagnetic Counterparts, and Nucleosynthesis , 2018, The Astrophysical Journal.

[22]  D. Siegel,et al.  Three-dimensional GRMHD Simulations of Neutrino-cooled Accretion Disks from Neutron Star Mergers , 2017, 1711.00868.

[23]  J. Sollerman,et al.  Impact of ejecta morphology and composition on the electromagnetic signatures of neutron star mergers , 2017, 1705.07084.

[24]  A. J. van der Horst,et al.  The second-closest gamma-ray burst: sub-luminous GRB 111005A with no supernova in a super-solar metallicity environment , 2016, Astronomy & Astrophysics.

[25]  Kohta Murase,et al.  GAMMA-RAY BURSTS : LONG-LASTING HIGH-ENERGY SIGNATURES AND REMNANT DICHOTOMY , 2018 .

[26]  L. S. Collaboration,et al.  Gravitational Waves and Gamma-rays from a Binary Neutron Star Merger: GW170817 and GRB 170817A , 2017 .

[27]  Larry Denneau,et al.  A kilonova as the electromagnetic counterpart to a gravitational-wave source , 2017, Nature.

[28]  The Ligo Scientific Collaboration,et al.  GW170817: Observation of Gravitational Waves from a Binary Neutron Star Inspiral , 2017, 1710.05832.

[29]  P. Schipani,et al.  Spectroscopic identification of r-process nucleosynthesis in a double neutron-star merger , 2017, Nature.

[30]  J. Prieto,et al.  Light curves of the neutron star merger GW170817/SSS17a: Implications for r-process nucleosynthesis , 2017, Science.

[31]  F. Collaboration Fermi-LAT observations of the LIGO/Virgo event GW170817 , 2017, 1710.05450.

[32]  G. Smoot,et al.  Thermal and non-thermal emission from the cocoon of a gamma-ray burst jet , 2017, 1701.05198.

[33]  N. Masetti,et al.  The gamma-ray blazar quest: new optical spectra, state of art and future perspectives , 2016, 1609.09502.

[34]  J. Lippuner,et al.  r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE , 2015, 1508.03133.

[35]  Bing Zhang,et al.  The physics of gamma-ray bursts & relativistic jets , 2014, 1410.0679.

[36]  Tum,et al.  Comprehensive nucleosynthesis analysis for ejecta of compact binary mergers , 2014, 1406.2687.

[37]  G. Smoot,et al.  Some implications of inverse-Compton scattering of hot cocoon radiation by relativistic jets in gamma-ray bursts , 2014, 1402.2656.

[38]  E. Berger Short-Duration Gamma-Ray Bursts , 2013, 1311.2603.

[39]  K. Wiersema,et al.  A ‘kilonova’ associated with the short-duration γ-ray burst GRB 130603B , 2013, Nature.

[40]  E. Berger,et al.  AN r-PROCESS KILONOVA ASSOCIATED WITH THE SHORT-HARD GRB 130603B , 2013, 1306.3960.

[41]  Juergen Knoedlseder,et al.  THE FIRST FERMI-LAT CATALOG OF SOURCES ABOVE 10 GeV , 2013, 1306.6772.

[42]  D. Kasen,et al.  OPACITIES AND SPECTRA OF THE r-PROCESS EJECTA FROM NEUTRON STAR MERGERS , 2013, 1303.5788.

[43]  Jennifer Barnes,et al.  EFFECT OF A HIGH OPACITY ON THE LIGHT CURVES OF RADIOACTIVELY POWERED TRANSIENTS FROM COMPACT OBJECT MERGERS , 2013, 1303.5787.

[44]  K. Hotokezaka,et al.  Mass ejection from the merger of binary neutron stars , 2012, 1212.0905.

[45]  S. Rosswog,et al.  On the astrophysical robustness of the neutron star merger r-process , 2012, 1206.2379.

[46]  M. C. Medina,et al.  A MODEL FOR THE HIGH-ENERGY EMISSION FROM BLAZARS , 2012 .

[47]  T. Piran,et al.  On the lateral expansion of gamma-ray burst jets , 2011, 1109.6468.

[48]  Garching,et al.  r-PROCESS NUCLEOSYNTHESIS IN DYNAMICALLY EJECTED MATTER OF NEUTRON STAR MERGERS , 2011, 1107.0899.

[49]  K. Toma,et al.  ON THE IMPLICATIONS OF LATE INTERNAL DISSIPATION FOR SHALLOW-DECAY AFTERGLOW EMISSION AND ASSOCIATED HIGH-ENERGY GAMMA-RAY SIGNALS , 2010, 1011.0988.

[50]  Douglas P. Finkbeiner,et al.  MEASURING REDDENING WITH SLOAN DIGITAL SKY SURVEY STELLAR SPECTRA AND RECALIBRATING SFD , 2010, 1012.4804.

[51]  P. N. Bhat,et al.  FERMI OBSERVATIONS OF GRB 090510: A SHORT–HARD GAMMA-RAY BURST WITH AN ADDITIONAL, HARD POWER-LAW COMPONENT FROM 10 keV TO GeV ENERGIES , 2010, 1005.2141.

[52]  N. T. Zinner,et al.  Electromagnetic counterparts of compact object mergers powered by the radioactive decay of r‐process nuclei , 2010, 1001.5029.

[53]  Xue-Feng Wu,et al.  SUBMITTED TO APJ Preprint typeset using LATEX style emulateapj v. 10/09/06 AN UP-SCATTERED COCOON EMISSION MODEL OF GAMMA-RAY BURST HIGH-ENERGY LAGS , 2022 .

[54]  J. P. Osborne,et al.  Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs , 2008, 0812.3662.

[55]  Anatoly Spitkovsky,et al.  Particle Acceleration in Relativistic Collisionless Shocks: Fermi Process at Last? , 2008, 0802.3216.

[56]  Bing Zhang,et al.  A Comprehensive Analysis of Swift XRT Data. II. Diverse Physical Origins of the Shallow Decay Segment , 2007, 0705.1373.

[57]  T. Piran,et al.  High-energy afterglow emission from gamma-ray bursts , 2007, 0704.2063.

[58]  N. Gehrels,et al.  The First Survey of X-Ray Flares from Gamma-Ray Bursts Observed by Swift: Temporal Properties and Morphology , 2007, astro-ph/0702371.

[59]  C. Firmani,et al.  “Late Prompt” Emission in Gamma-Ray Bursts? , 2007, astro-ph/0701430.

[60]  S. Rosswog Fallback accretion in the aftermath of a compact binary merger , 2006, astro-ph/0611440.

[61]  T. Piran,et al.  Sub-GeV flashes in γ-ray burst afterglows as probes of underlying bright far-ultraviolet flares , 2006, astro-ph/0601619.

[62]  P. Mészáros,et al.  GeV-TeV and X-Ray Flares from Gamma-Ray Bursts , 2006, astro-ph/0601229.

[63]  N. Gehrels,et al.  Evidence for a Canonical Gamma-Ray Burst Afterglow Light Curve in the Swift XRT Data , 2005, astro-ph/0508332.

[64]  N. Gehrels,et al.  The Giant X-Ray Flare of GRB 050502B: Evidence for Late-Time Internal Engine Activity , 2005, astro-ph/0512615.

[65]  D. Burrows,et al.  Physical Processes Shaping Gamma-Ray Burst X-Ray Afterglow Light Curves: Theoretical Implications from the Swift X-Ray Telescope Observations , 2005, astro-ph/0508321.

[66]  N. Gehrels,et al.  Bright X-ray Flares in Gamma-Ray Burst Afterglows , 2005, Science.

[67]  W. B. Burton,et al.  The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI - Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections , 2005, astro-ph/0504140.

[68]  Bing Zhang,et al.  Early Photon-Shock Interaction in a Stellar Wind: A Sub-GeV Photon Flash and High-Energy Neutrino Emission from Long Gamma-Ray Bursts , 2005, astro-ph/0504039.

[69]  A. Beloborodov,et al.  Optical and GeV-TeV Flashes from Gamma-Ray Bursts , 2004, astro-ph/0410050.

[70]  Ryan Chornock,et al.  The Katzman Automatic Imaging Telescope Gamma‐Ray Burst Alert System, and Observations of GRB 020813 , 2003, astro-ph/0305027.

[71]  Bing Zhang,et al.  GAMMA-RAY BURST AFTERGLOW WITH CONTINUOUS ENERGY INJECTION: SIGNATURE OF A HIGHLY MAGNETIZED MILLISECOND PULSAR , 2000 .

[72]  A. Kumar,et al.  Analytic Light Curves of Gamma-Ray Burst Afterglows: Homogeneous versus Wind External Media , 2000, astro-ph/0003246.

[73]  Tsvi Piran,et al.  Predictions for the Very Early Afterglow and the Optical Flash , 1999, astro-ph/9901338.

[74]  Bohdan Paczy'nski,et al.  Transient Events from Neutron Star Mergers , 1998, astro-ph/9807272.

[75]  J. Hjorth,et al.  The Supernova-Gamma-Ray Burst Connection , 1998, astro-ph/9806212.

[76]  T. Piran,et al.  Spectra and Light Curves of Gamma-Ray Burst Afterglows , 1997, astro-ph/9712005.

[77]  Z. Dai,et al.  Gamma-ray burst afterglows and evolution of postburst fireballs with energy injection from strongly magnetic millisecond pulsars , 1998 .

[78]  Cambridge,et al.  Cooling Timescales and Temporal Structure of Gamma-Ray Bursts , 1996, astro-ph/9605005.

[79]  M. Rees,et al.  Unsteady outflow models for cosmological gamma-ray bursts , 1994, astro-ph/9404038.

[80]  Martin J. Rees,et al.  Comptonization of Diffuse Ambient Radiation by a Relativistic Jet: The Source of Gamma Rays from Blazars? , 1994 .

[81]  C. Kouveliotou,et al.  Identification of two classes of gamma-ray bursts , 1993 .

[82]  J. Rhoads,et al.  Radio Transients from Gamma-Ray Bursters , 1993, astro-ph/9307024.

[83]  T. Piran,et al.  Gamma-ray bursts as the death throes of massive binary stars , 1992, astro-ph/9204001.