FERMI OBSERVATIONS OF GRB 090510: A SHORT–HARD GAMMA-RAY BURST WITH AN ADDITIONAL, HARD POWER-LAW COMPONENT FROM 10 keV TO GeV ENERGIES

By M. Ackermann, K. Asano, W. Atwood, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M. Baring, D. Bastieri, K. Bechtol and 169 more. 2010

293 citations recorded by the source corpus.

We present detailed observations of the bright short–hard gamma-ray burst GRB 090510 made with the Gamma-ray Burst Monitor (GBM) and Large Area Telescope (LAT) on board the Fermi observatory. GRB 090510 is the first burst detected by the LAT that shows strong evidence for a deviation from a Band spectral fitting function during the prompt emission phase. The time-integrated spectrum is fit by the sum of a Band function with Epeak = 3.9 ± 0.3 MeV, which is the highest yet measured, and a hard power-law component with photon index −1.62 ± 0.03 that dominates the emission below ≈20 keV and above ≈100 MeV. The onset of the high-energy spectral component appears to be delayed by ∼0.1 s with respect to the onset of a component well fit with a single Band function. A faint GBM pulse and a LAT photon are detected 0.5 s before the main pulse. During the prompt phase, the LAT detected a photon with energy 30.5+5.8−2.6 GeV, the highest ever measured from a short GRB. Observation of this photon sets a minimum bulk outflow Lorentz factor, Γ≳ 1200, using simple γγ opacity arguments for this GRB at redshift z = 0.903 and a variability timescale on the order of tens of ms for the ≈100 keV–few MeV flux. Stricter high confidence estimates imply Γ ≳ 1000 and still require that the outflows powering short GRBs are at least as highly relativistic as those of long-duration GRBs. Implications of the temporal behavior and power-law shape of the additional component on synchrotron/synchrotron self-Compton, external-shock synchrotron, and hadronic models are considered.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/b1ee95b914dec695773b4549c78739c20efc7ee1

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In Astronomy and Astrophysics

1. Bing Zhang
2. Pawan Kumar
3. E. Liang
4. E. Berger
5. F. Ryde
6. A. Pe’er
7. Binbin Zhang
8. B. Metzger

In Nuclear and High Energy Physics

1. Bing Zhang
2. J. Biteau
3. G. Ghisellini
4. F. Ryde
5. L. Sironi
6. A. Spitkovsky
7. Anna Franckowiak
8. E. Orlando

Citations in the corpus

• Relativistic Shocks: Particle Acceleration and Magnetization (2015, background): “The synchrotron radiation of electrons accelerated at the external ultra-relativistic shock of GRBs can thus produce the bulk of the long-lasting > 100 MeV emission detected by the Fermi satellite (e.g. Kumar and Barniol Duran 2009; Ackermann 2010; De Pasquale 2010; Ghisellini et al. 2010).”
• A COMPREHENSIVE ANALYSIS OF FERMI GAMMA-RAY BURST DATA. I. SPECTRAL COMPONENTS AND THE POSSIBLE PHYSICAL ORIGINS OF LAT/GBM GRBs (2010, background): “However, in order to investigate spectral evolution and the interplay between the MeV component and the extra PL component, we nonetheless make 4 time bins (see also Ackermann et al. 2010).”
• Detection of a Spectral Break in the Extra Hard Component of GRB 090926A (2011, background): “The lower allowed values of Γ also reduce the energy requirements in photohadronic models, where non-thermal protons usually dominate the bulk energy (Asano et al. 2009; Wang et al. 2009; Ackermann et al. 2010a).”
• DETECTION OF A THERMAL SPECTRAL COMPONENT IN THE PROMPT EMISSION OF GRB 100724B (2010, background): “…of an additional PL to the Band function sometimes extending from the lower energy in the GBM to the higher energy in the LAT (Abdo et al. 2009; Ackermann et al. 2010a,b; Guiriec et al. 2010), in the case of GRB 100724B a PL spectral component does not improve on the Band-only fit and an…”
• A theory of photospheric emission from relativistic, collimated outflows (2012, background): “Multiple spectral components have been clearly identified in several GRBs after the launch of the Fermi telescope (Abdo et al. 2009; Ackermann et al. 2010, 2011).”
• THE FIRST FERMI-LAT GAMMA-RAY BURST CATALOG (2013, background): “One of the first results by Fermi was the need for multi-component spectral models for some GRBs, showing a high-energy excess over the main component that has been modeled with an additional PL (Ackermann et al. 2010b; Abdo et al. 2009a).”
• GRB110721A: AN EXTREME PEAK ENERGY AND SIGNATURES OF THE PHOTOSPHERE (2012, background): “Fermi observations of GRB090510 showed a peak energy of ∼ 5 MeV (Ackermann et al. 2010).”
• Gamma-ray bursts in the comoving frame (2011, background): “The interpretation of the GeV emission as afterglow (Barniol Duran & Kumar 2009, Ghirlandet al. 2010, Ghisellini et al. 2010) is however debated (Ackermann et al. 2010; Piran & Nakar 2010).”
• Search for TeV Gamma-ray Emission from GRB 100621A, an extremely bright GRB in X-rays, with H.E.S.S (2014, background): “…is consistent with a Band function from keV to GeV energies, whereas other bursts show an additional hard power-law component at HE (e.g. GRB 090902B & 090510, Abdo et al. 2009a; Ackermann et al. 2010), which in some cases exhibits a spectral break (e.g. GRB 090926A, Ackermann et al. 2011).”
• Short-Duration Gamma-Ray Bursts (2013, background): “…emission in both long and short GRBs have been interpreted as evidence for a hadronic orig n (Asano, Guiriec & Mészáros 2009), a synchrotron self-Compton origin (Ackermann et al. 2010), or an afterglow origin (Ackermann et al. 2010; Ghirlanda, Ghisellini & Nava 2010; Kumar & Barniol Duran 2010).”
• THE FERMI GBM GAMMA-RAY BURST SPECTRAL CATALOG: FOUR YEARS OF DATA (2014, background): “In addition, discoveries of new and intriguing phenomena were associated with many individual GRBs (e.g., Ackermann et al. 2010; Guiriec et al. 2011; Ackermann et al. 2011; Axelsson et al. 2012; Guiriec et al. 2013).”
• THE MISSING LINK: MERGING NEUTRON STARS NATURALLY PRODUCE JET-LIKE STRUCTURES AND CAN POWER SHORT GAMMA-RAY BURSTS (2011, background): “…SGRBs, Eγ,iso, spans a wide range, from (2.7 ± 1) × 1048 erg (in the observed energy range 15 − 350 keV) for GRB 050509B at a redshift of z = 0.225 (Bloom et al. 2006), up to (1.08 ± 0.06) × 1053 erg (in the observed energy range 10 keV – 30 GeV) for GRB 090510 at z = 0.903 (Ackermann et al. 2010).”
• An Ordinary Short Gamma-Ray Burst with Extraordinary Implications: Fermi-GBM Detection of GRB 170817A (2017, background): “This work was intended to inform the time range expected for EM counterparts to GWs, but little evidence was found for precursor activity in the GBM archive of more than 300 short GRBs, with few exceptions (e.g. Ackermann et al. 2010).”