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

Ackermann, M.; Asano, Katsuaki; Atwood, W. B.; Axelsson, M.; Baldini, Luca; Ballet, J.; Barbiellini, G.; Baring, Matthew G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bhat, P. N.; Bissaldi, E.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Briggs, M. S.; Brigida, M.; Bruel, Pascal; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Carrigan, S.; Casandjian, J. M.; Cecchi, C.; Çelik, Ö.; Charles, E.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Connaughton, V.; Conrad, J.; Dermer, C. D.; Palma, F. de; Dingus, B. L.; Silva, E. Do Couto E; Drell, P. S.; Dubois, R.; Dumora, D.; Farnier, C.; Favuzzi, C.; Fegan, S. J.; Finke, J.; Focke, W. B.; Frailis, M.; Fukazawa, Yasushi; Fusco, P.; Gargano, F.; Gasparrini, D.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Glanzman, T.; Godfrey, G.; Granot, Jonathan; Grenier, I. A.; Grondin, M.‐H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Harding, A. K.; Hays, E.; Horan, D.; Hughes, R. E.; Jóhannesson, G.; Johnson, W. N.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kawai, N.; Kippen, R. M.; Knödlseder, J.; Kocevski, D.; Kouveliotou, C.; Kuss, M.; Landé, J.; Latronico, L.; Lemoine‐Goumard, M.; Garde, M. Llena; Longo, F.; Loparco, F.; Lott, B.; Lovellette, M. N.; Lubrano, P.; Makeev, A.; Mazziotta, M. N.; McEnery, J. E.; McGlynn, S.; Meegan, C.; Mészáros, P.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Моисеев, А. А.; Monte, C.; Monzani, M. E.; Moretti, E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Nakajima, H.; Nakamori, Takeshi; Nolan, P. L.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, Masanori; Pačiesas, W. S.; Paneque, D.; Panetta, J.; Parent, D.; Pelassa, V.; Pepé, M.; Pesce-Rollins, M.; Piron, F.; Preece, R.; Rainò, S.; Rando, R.; Razzano, M.; Razzaque, S.; Reimer, A.; Ritz, S.; Rodriguez, A. Y.; Roth, M.; Ryde, F.; Sadrozinski, H. F-W.; Sander, A.; Scargle, Jeffrey D.; Schalk, T.; Sgrò, C.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Stamatikos, M.; Stecker, F. W.; Strickman, M. S.; Suson, D. J.; Tajima, H.; Takahashi, H.; Takahashi, T.; Tanaka, Takaaki; Thayer, J. B.; Thayer, J. G.; Thompson, D. J.; Tibaldo, L.; Toma, Kenji; Torres, D. F.; Tosti, G.; Tramacere, A.; Uchiyama, Y.; Uehara, T.; Usher, T.; Horst, A. J. van der; Vasileiou, V.; Vilchez, N.; Vitale, V.; Kienlin, A. von; Waite, A. P.; Wang, P.; Wilson-Hodge, C.; Winer, B. L.; Wu, Xue-Feng; Yamazaki, Ryo; Yang, Z.; Ylinen, T.; Ziegler, M.

doi:10.1088/0004-637x/716/2/1178

Cited by 354 publications

(364 citation statements)

References 55 publications

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“…This assumption is based on the pair creation constraint combined with the Fermi/LAT observations of the first bright GRBs (GRBs 080916C, 090510, and 090902B), whose spectrum do not exhibit any attenuation at GeV energies (Abdo et al 2009b,a;Ackermann et al 2010). However, later studies (Granot et al 2008;Hascoët et al 2012) pointed out that the single-zone model used in these early studies was not accurate enough.…”

Section: Discussionmentioning

confidence: 99%

Time evolution of the spectral break in the high-energy extra component of GRB 090926A

Yassine

Piron

Mochkovitch

et al. 2017

A&A

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Aims. The prompt light curve of the long GRB 090926A reveals a short pulse ∼10 s after the beginning of the burst emission, which has been observed by the Fermi observatory from the keV to the GeV energy domain. During this bright spike, the high-energy emission from GRB 090926A underwent a sudden hardening above 10 MeV in the form of an additional power-law component exhibiting a spectral attenuation at a few hundreds of MeV. This high-energy break has been previously interpreted in terms of gamma-ray opacity to pair creation and has been used to estimate the bulk Lorentz factor of the outflow. In this article, we report on a new time-resolved analysis of the GRB 090926A broadband spectrum during its prompt phase and on its interpretation in the framework of prompt emission models. Methods. We characterized the emission from GRB 090926A at the highest energies with Pass 8 data from the Fermi Large Area Telescope (LAT), which offer a greater sensitivity than any data set used in previous studies of this burst, particularly in the 30−100 MeV energy band. Then, we combined the LAT data with the Fermi Gamma-ray Burst Monitor (GBM) in joint spectral fits to characterize the time evolution of the broadband spectrum from keV to GeV energies. We paid careful attention to the systematic effects that arise from the uncertainties on the LAT response. Finally, we performed a temporal analysis of the light curves and we computed the variability timescales from keV to GeV energies during and after the bright spike. Results. Our analysis confirms and better constrains the spectral break, which has been previously reported during the bright spike. Furthermore, it reveals that the spectral attenuation persists at later times with an increase of the break characteristic energy up to the GeV domain until the end of the prompt phase. We discuss these results in terms of keV−MeV synchroton radiation of electrons accelerated during the dissipation of the jet energy and inverse Compton emission at higher energies. We interpret the high-energy spectral break as caused by photon opacity to pair creation. Requiring that all emissions are produced above the photosphere of GRB 090926A, we compute the bulk Lorentz factor of the outflow, Γ. The latter decreases from 230 during the spike to 100 at the end of the prompt emission. Assuming, instead, that the spectral break reflects the natural curvature of the inverse Compton spectrum, lower limits corresponding to larger values of Γ are also derived. Combined with the extreme temporal variability of GRB 090926A, these Lorentz factors lead to emission radii R ∼ 10 14 cm, which are consistent with an internal origin of both the keV−MeV and GeV prompt emissions.

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Section: Discussionmentioning

confidence: 99%

Time evolution of the spectral break in the high-energy extra component of GRB 090926A

Yassine

Piron

Mochkovitch

et al. 2017

A&A

Self Cite

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“…De Pasquale et al (2010 built the multiwavelength spectral energy distribution (SED) from simultaneous observations of Swift and Fermi. Synchrotron and SSC were proposed to be the origins of the keV-MeV emission and an additional component above the GeV band, respectively (Ackermann et al 2010b), and a large bulk Lorentz factor Γ > 500-1000 was required. However, it is difficult to apply the simple model presented in this paper for this burst for two reasons.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

“…However, it is difficult to apply the simple model presented in this paper for this burst for two reasons. (1) A hard power-law component dominates the emission both below 20 keV and above 100 MeV (Ackermann et al 2010b). The JSC process can be adopted to explain the emission above 100 MeV, but it cannot explain the emission below 20 keV.…”

Section: Conclusion and Discussionmentioning

confidence: 99%

JITTER SELF-COMPTON PROCESS: GeV EMISSION OF GRB 100728A

Mao

Wang

2012

ApJ

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Jitter radiation, the emission of relativistic electrons in a random and small-scale magnetic field, has been applied to explain the gamma-ray burst (GRB) prompt emission. The seed photons produced from jitter radiation can be scattered by thermal/nonthermal electrons to the high-energy bands. This mechanism is called jitter self-Compton (JSC) radiation. GRB 100728A, which was simultaneously observed by Swift and Fermi, is a great example to constrain the physical processes of jitter and JSC. In our work, we utilize jitter/JSC radiation to reproduce the multiwavelength spectrum of GRB 100728A. In particular, due to JSC radiation, the powerful emission above the GeV band is the result of those jitter photons in the X-ray band scattered by the relativistic electrons with a mixed thermal-nonthermal energy distribution. We also combine the geometric effect of microemitters to the radiation mechanism, such that the "jet-in-jet" scenario is considered. The observed GRB duration is the result of summing up all of the contributions from those microemitters in the bulk jet.

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“…Secondly, the optical depth for such high energy photons can be large in the prompt phase Beloborodov 2010;Chang et al 2012a). This will lead to the time lag phenomenons for GeV photons in GRB Abdo et al (2009a,b); Ackermann et al (2010Ackermann et al ( , 2011. The production of such photon collision is pairs of electron and position.…”

Section: The Spectra Of Photonsmentioning

confidence: 99%

Time-resolved GRB spectra in the complex radiation of synchrotron and Compton processes

Jiang¹,

Hu²,

Chen³

et al. 2016

Mon. Not. R. Astron. Soc.

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Under the steady state condition, the spectrum of electrons is investigated by solving the continuity equation under the complex radiation of both the synchrotron and Compton processes. The resulted GRB spectrum is a broken power law in both the fast and slow cooling phases. On the basis of this electron spectrum, the spectral indices of the Band function in four different phases are presented. In the complex radiation frame, the detail investigation on physical parameters reveals that both the reverse shock photosphere model and the forward shock with strong coupling model can answer the α ∼ −1 problem. A possible marginal to fast cooling phase transition in GRB 080916C is discussed. The time resolved spectra in different pulses of GRB 100724B, GRB 100826A and GRB 130606B are investigated. We found that the flux is proportional to the peak energy in almost all pulses. The phases for different pulses are determined according to the spectral index revolution. We found the strong correlations between spectral indices and the peak energy in GRB 100826A, which can be explained by the Compton effect in the fast cooling phase. However, the complex scenario predicts a steeper index for the injected electrons, which challenges the acceleration mechanism in GRBs. ‡

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

Cited by 354 publications

References 55 publications

Time evolution of the spectral break in the high-energy extra component of GRB 090926A

Time evolution of the spectral break in the high-energy extra component of GRB 090926A

JITTER SELF-COMPTON PROCESS: GeV EMISSION OF GRB 100728A

Time-resolved GRB spectra in the complex radiation of synchrotron and Compton processes

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