Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow

M. Ackermann; M. Ajello; K. Asano; L. Baldini; G. Barbiellini; M. G. Baring; D. Bastieri; R. Bellazzini; R. D. Blandford; E. Bonamente; A. W. Borgland; E. Bottacini; J. Bregeon; M. Brigida; P. Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; C. Cecchi; E. Charles; R. C.G. Chaves; A. Chekhtman; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Cutini; F. D'Ammando; A. De Angelis; F. De Palma; C. D. Dermer; E. Do Couto E Silva; P. S. Drell; A. Drlica-Wagner; C. Favuzzi; S. J. Fegan; W. B. Focke; A. Franckowiak; Y. Fukazawa; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; N. Giglietto; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; J. Granot; J. Greiner; I. A. Grenier; J. E. Grove; S. Guiriec; D. Hadasch; Y. Hanabata; M. Hayashida; E. Hays; R. E. Hughes; M. S. Jackson; T. Jogler; G. Jóhannesson; A. S. Johnson; J. Knödlseder; D. Kocevski; M. Kuss; J. Lande; S. Larsson; L. Latronico; F. Longo; F. Loparco; M. N. Lovellette; P. Lubrano; M. N. Mazziotta; J. E. McEnery; J. Mehault; P. Mészáros; P. F. Michelson; W. Mitthumsiri; T. Mizuno; C. Monte; M. E. Monzani; E. Moretti; A. Morselli; I. V. Moskalenko; S. Murgia; M. Naumann-Godo; J. P. Norris; E. Nuss; T. Nymark; M. Ohno; T. Ohsugi; N. Omodei; M. Orienti; E. Orlando; D. Paneque; J. S. Perkins; M. Pesce-Rollins; F. Piron; G. Pivato; J. L. Racusin; S. Rainò; R. Rando; M. Razzano; S. Razzaque; A. Reimer; O. Reimer; C. Romoli; M. Roth; F. Ryde; D. A. Sanchez; C. Sgrò; E. J. Siskind; E. Sonbas; P. Spinelli; M. Stamatikos; H. Takahashi; T. Tanaka; J. G. Thayer; J. B. Thayer; L. Tibaldo; M. Tinivella; G. Tosti; E. Troja; T. L. Usher; J. Vandenbroucke; V. Vasileiou; G. Vianello; V. Vitale; A. P. Waite; B. L. Winer; K. S. Wood; Z. Yang; D. Gruber; P. N. Bhat; E. Bissaldi; M. S. Briggs; J. M. Burgess; V. Connaughton; S. Foley; R. M. Kippen; C. Kouveliotou; S. McBreen; S. McGlynn; W. S. Paciesas; V. Pelassa; R. Preece; A. Rau; A. J. Van Der Horst; A. Von Kienlin; D. A. Kann; R. Filgas; S. Klose; T. Krühler; A. Fukui; T. Sako; P. J. Tristram; S. R. Oates; T. N. Ukwatta; O. Littlejohns

doi:10.1088/0004-637X/763/2/71

Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow

M. Ackermann
, M. Ajello
, K. Asano
, L. Baldini
, G. Barbiellini
, M. G. Baring
, D. Bastieri
, R. Bellazzini
, R. D. Blandford
, E. Bonamente
, A. W. Borgland
, E. Bottacini
, J. Bregeon
, M. Brigida
, P. Bruel
, R. Buehler
, S. Buson
, G. A. Caliandro
, R. A. Cameron
, P. A. Caraveo

C. Cecchi, E. Charles, R. C.G. Chaves, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, S. Cutini, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, C. Favuzzi, S. J. Fegan, W. B. Focke, A. Franckowiak, Y. Fukazawa, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, J. Granot, J. Greiner, I. A. Grenier, J. E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, M. Hayashida, E. Hays, R. E. Hughes, M. S. Jackson, T. Jogler, G. Jóhannesson, A. S. Johnson, J. Knödlseder, D. Kocevski, M. Kuss, J. Lande, S. Larsson, L. Latronico, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. Mészáros, P. F. Michelson, W. Mitthumsiri, T. Mizuno, C. Monte, M. E. Monzani, E. Moretti, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, J. P. Norris, E. Nuss, T. Nymark, M. Ohno, T. Ohsugi, N. Omodei, M. Orienti, E. Orlando, D. Paneque, J. S. Perkins, M. Pesce-Rollins, F. Piron, G. Pivato, J. L. Racusin, S. Rainò, R. Rando, M. Razzano, S. Razzaque, A. Reimer, O. Reimer, C. Romoli, M. Roth, F. Ryde, D. A. Sanchez, C. Sgrò, E. J. Siskind, E. Sonbas, P. Spinelli, M. Stamatikos, H. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, L. Tibaldo, M. Tinivella, G. Tosti, E. Troja, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, B. L. Winer, K. S. Wood, Z. Yang, D. Gruber, P. N. Bhat, E. Bissaldi, M. S. Briggs, J. M. Burgess, V. Connaughton, S. Foley, R. M. Kippen, C. Kouveliotou, S. McBreen, S. McGlynn, W. S. Paciesas, V. Pelassa, R. Preece, A. Rau, A. J. Van Der Horst, A. Von Kienlin, D. A. Kann, R. Filgas, S. Klose, T. Krühler, A. Fukui, T. Sako, P. J. Tristram, S. R. Oates, T. N. Ukwatta, O. Littlejohns

c/o DESY
Stanford University
Interactive Research Center of Science
Tokyo Institute of Technology
Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
INFN Gruppo Collegato di Udine
INFN Sezione di Trieste
Dipartimento di Fisica
University of Trieste
Department of Physics and Astronomy
Rice University
INFN
Dipartimento di Fisica e Astronomia G. Galilei
University of Padova
Sezione di Perugia
INFN Sezione di Perugia
INFM CRS-SOFT
University of Perugia
Politecnico di Bari
INFN
INFN Sezione di Bari
University of Sheffield
INAF Istituto di Astrofisica Spaziale e Fisica Cosmica, Milan
Laboratoire AIM
Universite Paris-Saclay
Center for Earth Observing and Space Research
George Mason University
Naval Research Laboratory
ASI Science Data Center
Laboratoire Univers et Particules de Montpellier
Department of Physics
Stockholm University
Oskar Klein Centre
Science and Research Directorate
INAF Istituto di Astrofisica Spaziale e Fisica Cosmica di Palermo
INAF-IASF
Dipartimento di Fisica
and Physics University of Udine
Space Science Division
Department of Physical Science
Hiroshima University
NASA Goddard Space Flight Center
INAF Istituto di Radioastronomia
Centre for Astrophysics Research
University of Hertfordshire
Max Planck Institut für Extraterrestrische Physik
Center for Space Plasma and Aeronomic Research
Department of Astronomy
Kyoto University
Department of Physics
The Ohio State University
KTH Royal Institute of Technology
University of Iceland
IRAP/CNRS
Department of Astronomy
Sezione di Torino
INFN Sezione di Torino
University of Maryland
Department of Astronomy and Astrophysics
Pennsylvania State University
Hiroshima Astrophysical Science Center
Sezione di Roma
Department of Physics
Boise State University
ISAS/JAXA
Max-Planck-Institut für Physik
Department of Physics
Biochemical and Environmental Engineering
Center for Research and Exploration in Space Science and Technology (CRESST)
Center for Astrophysics | Harvard & Smithsonian
University of California at Santa Cruz
Medical University of Innsbruck
Department of Physics
University of Washington
Max-Planck-Institut für Kernphysik
NYCB Real-Time Computing Inc.
Faculty of Arts and Sciences
Adiyaman University
Universities Space Research Association
Consorzio Interuniversitario per la Fisica Spaziale (CIFS)
Dipartimento di Fisica
University of Rome “Tor Vergata”
School of Physics
University College Dublin
MST-8, Los Alamos National Laboratory
NASA Marshall Space Flight Center
Technical University of Munich
Thüringer Landessternwarte Tautenburg
Institute of Experimental and Applied Physics Czech Technical University in Prague
Niels Bohr Institutet
National Astronomical Observatory
Solar-Terrestrial Environment Laboratory
Nagoya University
Victoria University of Wellington
UCL Mullard Space Science Laboratory
Department of Physics and Astronomy
Michigan State University
University of Leicester

Research output: Contribution to journal › Article › peer-review

92 Citations (Scopus)

Abstract

We report on the multiwavelength observations of the bright, long gamma-ray burst GRB 110731A, by the Fermi and Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that GRB 110731A shares many features with bright Large Area Telescope bursts observed by Fermi during the first three years on-orbit: a light curve with short time variability across the whole energy range during the prompt phase, delayed onset of the emission above 100 MeV, extra power-law component and temporally extended high-energy emission. In addition, this is the first GRB for which simultaneous GeV, X-ray, and optical data are available over multiple epochs beginning just after the trigger time and extending for more than 800 s, allowing temporal and spectral analysis in different epochs that favor emission from the forward shock in a wind-type medium. The observed temporally extended GeV emission is most likely part of the high-energy end of the afterglow emission. Both the single-zone pair transparency constraint for the prompt signal and the spectral and temporal analysis of the forward-shock afterglow emission independently lead to an estimate of the bulk Lorentz factor of the jet Γ ∼ 500-550.

Original language	English
Article number	71
Journal	Astrophysical Journal
Volume	763
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/763/2/71
Publication status	Published - 1 Feb 2013

Keywords

gamma-ray burst: individual (GRB110731A)

Access to Document

10.1088/0004-637X/763/2/71

Cite this

Ackermann, M., Ajello, M., Asano, K., Baldini, L., Barbiellini, G., Baring, M. G., Bastieri, D., Bellazzini, R., Blandford, R. D., Bonamente, E., Borgland, A. W., Bottacini, E., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., ... Littlejohns, O. (2013). Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow. Astrophysical Journal, 763(2), Article 71. https://doi.org/10.1088/0004-637X/763/2/71

@article{8353b1aff2464c189e940f16fcb1d56a,

title = "Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow",

abstract = "We report on the multiwavelength observations of the bright, long gamma-ray burst GRB 110731A, by the Fermi and Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that GRB 110731A shares many features with bright Large Area Telescope bursts observed by Fermi during the first three years on-orbit: a light curve with short time variability across the whole energy range during the prompt phase, delayed onset of the emission above 100 MeV, extra power-law component and temporally extended high-energy emission. In addition, this is the first GRB for which simultaneous GeV, X-ray, and optical data are available over multiple epochs beginning just after the trigger time and extending for more than 800 s, allowing temporal and spectral analysis in different epochs that favor emission from the forward shock in a wind-type medium. The observed temporally extended GeV emission is most likely part of the high-energy end of the afterglow emission. Both the single-zone pair transparency constraint for the prompt signal and the spectral and temporal analysis of the forward-shock afterglow emission independently lead to an estimate of the bulk Lorentz factor of the jet Γ ∼ 500-550.",

keywords = "gamma-ray burst: individual (GRB110731A)",

author = "M. Ackermann and M. Ajello and K. Asano and L. Baldini and G. Barbiellini and Baring, \{M. G.\} and D. Bastieri and R. Bellazzini and Blandford, \{R. D.\} and E. Bonamente and Borgland, \{A. W.\} and E. Bottacini and J. Bregeon and M. Brigida and P. Bruel and R. Buehler and S. Buson and Caliandro, \{G. A.\} and Cameron, \{R. A.\} and Caraveo, \{P. A.\} and C. Cecchi and E. Charles and Chaves, \{R. C.G.\} and A. Chekhtman and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and J. Conrad and S. Cutini and F. D'Ammando and \{De Angelis\}, A. and \{De Palma\}, F. and Dermer, \{C. D.\} and \{Do Couto E Silva\}, E. and Drell, \{P. S.\} and A. Drlica-Wagner and C. Favuzzi and Fegan, \{S. J.\} and Focke, \{W. B.\} and A. Franckowiak and Y. Fukazawa and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and N. Giglietto and F. Giordano and M. Giroletti and T. Glanzman and G. Godfrey and J. Granot and J. Greiner and Grenier, \{I. A.\} and Grove, \{J. E.\} and S. Guiriec and D. Hadasch and Y. Hanabata and M. Hayashida and E. Hays and Hughes, \{R. E.\} and Jackson, \{M. S.\} and T. Jogler and G. J{\'o}hannesson and Johnson, \{A. S.\} and J. Kn{\"o}dlseder and D. Kocevski and M. Kuss and J. Lande and S. Larsson and L. Latronico and F. Longo and F. Loparco and Lovellette, \{M. N.\} and P. Lubrano and Mazziotta, \{M. N.\} and McEnery, \{J. E.\} and J. Mehault and P. M{\'e}sz{\'a}ros and Michelson, \{P. F.\} and W. Mitthumsiri and T. Mizuno and C. Monte and Monzani, \{M. E.\} and E. Moretti and A. Morselli and Moskalenko, \{I. V.\} and S. Murgia and M. Naumann-Godo and Norris, \{J. P.\} and E. Nuss and T. Nymark and M. Ohno and T. Ohsugi and N. Omodei and M. Orienti and E. Orlando and D. Paneque and Perkins, \{J. S.\} and M. Pesce-Rollins and F. Piron and G. Pivato and Racusin, \{J. L.\} and S. Rain{\`o} and R. Rando and M. Razzano and S. Razzaque and A. Reimer and O. Reimer and C. Romoli and M. Roth and F. Ryde and Sanchez, \{D. A.\} and C. Sgr{\`o} and Siskind, \{E. J.\} and E. Sonbas and P. Spinelli and M. Stamatikos and H. Takahashi and T. Tanaka and Thayer, \{J. G.\} and Thayer, \{J. B.\} and L. Tibaldo and M. Tinivella and G. Tosti and E. Troja and Usher, \{T. L.\} and J. Vandenbroucke and V. Vasileiou and G. Vianello and V. Vitale and Waite, \{A. P.\} and Winer, \{B. L.\} and Wood, \{K. S.\} and Z. Yang and D. Gruber and Bhat, \{P. N.\} and E. Bissaldi and Briggs, \{M. S.\} and Burgess, \{J. M.\} and V. Connaughton and S. Foley and Kippen, \{R. M.\} and C. Kouveliotou and S. McBreen and S. McGlynn and Paciesas, \{W. S.\} and V. Pelassa and R. Preece and A. Rau and \{Van Der Horst\}, \{A. J.\} and \{Von Kienlin\}, A. and Kann, \{D. A.\} and R. Filgas and S. Klose and T. Kr{\"u}hler and A. Fukui and T. Sako and Tristram, \{P. J.\} and Oates, \{S. R.\} and Ukwatta, \{T. N.\} and O. Littlejohns",

year = "2013",

month = feb,

day = "1",

doi = "10.1088/0004-637X/763/2/71",

language = "English",

volume = "763",

journal = "Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Ackermann, M, Ajello, M, Asano, K, Baldini, L, Barbiellini, G, Baring, MG, Bastieri, D, Bellazzini, R, Blandford, RD, Bonamente, E, Borgland, AW, Bottacini, E, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Cecchi, C, Charles, E, Chaves, RCG, Chekhtman, A, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, Cutini, S, D'Ammando, F, De Angelis, A, De Palma, F, Dermer, CD, Do Couto E Silva, E, Drell, PS, Drlica-Wagner, A, Favuzzi, C, Fegan, SJ, Focke, WB, Franckowiak, A, Fukazawa, Y, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Granot, J, Greiner, J, Grenier, IA, Grove, JE, Guiriec, S, Hadasch, D, Hanabata, Y, Hayashida, M, Hays, E, Hughes, RE, Jackson, MS, Jogler, T, Jóhannesson, G, Johnson, AS, Knödlseder, J, Kocevski, D, Kuss, M, Lande, J, Larsson, S, Latronico, L, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Mazziotta, MN, McEnery, JE, Mehault, J, Mészáros, P, Michelson, PF, Mitthumsiri, W, Mizuno, T, Monte, C, Monzani, ME, Moretti, E, Morselli, A, Moskalenko, IV, Murgia, S, Naumann-Godo, M, Norris, JP, Nuss, E, Nymark, T, Ohno, M, Ohsugi, T, Omodei, N, Orienti, M, Orlando, E, Paneque, D, Perkins, JS, Pesce-Rollins, M, Piron, F, Pivato, G, Racusin, JL, Rainò, S, Rando, R, Razzano, M, Razzaque, S, Reimer, A, Reimer, O, Romoli, C, Roth, M, Ryde, F, Sanchez, DA, Sgrò, C, Siskind, EJ, Sonbas, E, Spinelli, P, Stamatikos, M, Takahashi, H, Tanaka, T, Thayer, JG, Thayer, JB, Tibaldo, L, Tinivella, M, Tosti, G, Troja, E, Usher, TL, Vandenbroucke, J, Vasileiou, V, Vianello, G, Vitale, V, Waite, AP, Winer, BL, Wood, KS, Yang, Z, Gruber, D, Bhat, PN, Bissaldi, E, Briggs, MS, Burgess, JM, Connaughton, V, Foley, S, Kippen, RM, Kouveliotou, C, McBreen, S, McGlynn, S, Paciesas, WS, Pelassa, V, Preece, R, Rau, A, Van Der Horst, AJ, Von Kienlin, A, Kann, DA, Filgas, R, Klose, S, Krühler, T, Fukui, A, Sako, T, Tristram, PJ, Oates, SR, Ukwatta, TN & Littlejohns, O 2013, 'Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow', Astrophysical Journal, vol. 763, no. 2, 71. https://doi.org/10.1088/0004-637X/763/2/71

TY - JOUR

T1 - Multiwavelength observations of GRB 110731A

T2 - GeV emission from onset to afterglow

AU - Ackermann, M.

AU - Ajello, M.

AU - Asano, K.

AU - Baldini, L.

AU - Barbiellini, G.

AU - Baring, M. G.

AU - Bastieri, D.

AU - Bellazzini, R.

AU - Blandford, R. D.

AU - Bonamente, E.

AU - Borgland, A. W.

AU - Bottacini, E.

AU - Bregeon, J.

AU - Brigida, M.

AU - Bruel, P.

AU - Buehler, R.

AU - Buson, S.

AU - Caliandro, G. A.

AU - Cameron, R. A.

AU - Caraveo, P. A.

AU - Cecchi, C.

AU - Charles, E.

AU - Chaves, R. C.G.

AU - Chekhtman, A.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cohen-Tanugi, J.

AU - Conrad, J.

AU - Cutini, S.

AU - D'Ammando, F.

AU - De Angelis, A.

AU - De Palma, F.

AU - Dermer, C. D.

AU - Do Couto E Silva, E.

AU - Drell, P. S.

AU - Drlica-Wagner, A.

AU - Favuzzi, C.

AU - Fegan, S. J.

AU - Focke, W. B.

AU - Franckowiak, A.

AU - Fukazawa, Y.

AU - Fusco, P.

AU - Gargano, F.

AU - Gasparrini, D.

AU - Gehrels, N.

AU - Giglietto, N.

AU - Giordano, F.

AU - Giroletti, M.

AU - Glanzman, T.

AU - Godfrey, G.

AU - Granot, J.

AU - Greiner, J.

AU - Grenier, I. A.

AU - Grove, J. E.

AU - Guiriec, S.

AU - Hadasch, D.

AU - Hanabata, Y.

AU - Hayashida, M.

AU - Hays, E.

AU - Hughes, R. E.

AU - Jackson, M. S.

AU - Jogler, T.

AU - Jóhannesson, G.

AU - Johnson, A. S.

AU - Knödlseder, J.

AU - Kocevski, D.

AU - Kuss, M.

AU - Lande, J.

AU - Larsson, S.

AU - Latronico, L.

AU - Longo, F.

AU - Loparco, F.

AU - Lovellette, M. N.

AU - Lubrano, P.

AU - Mazziotta, M. N.

AU - McEnery, J. E.

AU - Mehault, J.

AU - Mészáros, P.

AU - Michelson, P. F.

AU - Mitthumsiri, W.

AU - Mizuno, T.

AU - Monte, C.

AU - Monzani, M. E.

AU - Moretti, E.

AU - Morselli, A.

AU - Moskalenko, I. V.

AU - Murgia, S.

AU - Naumann-Godo, M.

AU - Norris, J. P.

AU - Nuss, E.

AU - Nymark, T.

AU - Ohno, M.

AU - Ohsugi, T.

AU - Omodei, N.

AU - Orienti, M.

AU - Orlando, E.

AU - Paneque, D.

AU - Perkins, J. S.

AU - Pesce-Rollins, M.

AU - Piron, F.

AU - Pivato, G.

AU - Racusin, J. L.

AU - Rainò, S.

AU - Rando, R.

AU - Razzano, M.

AU - Razzaque, S.

AU - Reimer, A.

AU - Reimer, O.

AU - Romoli, C.

AU - Roth, M.

AU - Ryde, F.

AU - Sanchez, D. A.

AU - Sgrò, C.

AU - Siskind, E. J.

AU - Sonbas, E.

AU - Spinelli, P.

AU - Stamatikos, M.

AU - Takahashi, H.

AU - Tanaka, T.

AU - Thayer, J. G.

AU - Thayer, J. B.

AU - Tibaldo, L.

AU - Tinivella, M.

AU - Tosti, G.

AU - Troja, E.

AU - Usher, T. L.

AU - Vandenbroucke, J.

AU - Vasileiou, V.

AU - Vianello, G.

AU - Vitale, V.

AU - Waite, A. P.

AU - Winer, B. L.

AU - Wood, K. S.

AU - Yang, Z.

AU - Gruber, D.

AU - Bhat, P. N.

AU - Bissaldi, E.

AU - Briggs, M. S.

AU - Burgess, J. M.

AU - Connaughton, V.

AU - Foley, S.

AU - Kippen, R. M.

AU - Kouveliotou, C.

AU - McBreen, S.

AU - McGlynn, S.

AU - Paciesas, W. S.

AU - Pelassa, V.

AU - Preece, R.

AU - Rau, A.

AU - Van Der Horst, A. J.

AU - Von Kienlin, A.

AU - Kann, D. A.

AU - Filgas, R.

AU - Klose, S.

AU - Krühler, T.

AU - Fukui, A.

AU - Sako, T.

AU - Tristram, P. J.

AU - Oates, S. R.

AU - Ukwatta, T. N.

AU - Littlejohns, O.

PY - 2013/2/1

Y1 - 2013/2/1

N2 - We report on the multiwavelength observations of the bright, long gamma-ray burst GRB 110731A, by the Fermi and Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that GRB 110731A shares many features with bright Large Area Telescope bursts observed by Fermi during the first three years on-orbit: a light curve with short time variability across the whole energy range during the prompt phase, delayed onset of the emission above 100 MeV, extra power-law component and temporally extended high-energy emission. In addition, this is the first GRB for which simultaneous GeV, X-ray, and optical data are available over multiple epochs beginning just after the trigger time and extending for more than 800 s, allowing temporal and spectral analysis in different epochs that favor emission from the forward shock in a wind-type medium. The observed temporally extended GeV emission is most likely part of the high-energy end of the afterglow emission. Both the single-zone pair transparency constraint for the prompt signal and the spectral and temporal analysis of the forward-shock afterglow emission independently lead to an estimate of the bulk Lorentz factor of the jet Γ ∼ 500-550.

AB - We report on the multiwavelength observations of the bright, long gamma-ray burst GRB 110731A, by the Fermi and Swift observatories, and by the MOA and GROND optical telescopes. The analysis of the prompt phase reveals that GRB 110731A shares many features with bright Large Area Telescope bursts observed by Fermi during the first three years on-orbit: a light curve with short time variability across the whole energy range during the prompt phase, delayed onset of the emission above 100 MeV, extra power-law component and temporally extended high-energy emission. In addition, this is the first GRB for which simultaneous GeV, X-ray, and optical data are available over multiple epochs beginning just after the trigger time and extending for more than 800 s, allowing temporal and spectral analysis in different epochs that favor emission from the forward shock in a wind-type medium. The observed temporally extended GeV emission is most likely part of the high-energy end of the afterglow emission. Both the single-zone pair transparency constraint for the prompt signal and the spectral and temporal analysis of the forward-shock afterglow emission independently lead to an estimate of the bulk Lorentz factor of the jet Γ ∼ 500-550.

KW - gamma-ray burst: individual (GRB110731A)

U2 - 10.1088/0004-637X/763/2/71

DO - 10.1088/0004-637X/763/2/71

M3 - Article

AN - SCOPUS:84872690981

SN - 0004-637X

VL - 763

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

M1 - 71

ER -

Multiwavelength observations of GRB 110731A: GeV emission from onset to afterglow

Abstract

Keywords

Access to Document

Fingerprint

Cite this