Detection of a spectral break in the extra hard component of GRB 090926A

M. Ackermann; M. Ajello; K. Asano; M. Axelsson; L. Baldini; J. Ballet; G. Barbiellini; M.G. Baring; D. Bastieri; K. Bechtol; R. Bellazzini; B. Berenji; P.N. Bhat; E. Bissaldi; R. Blandford; E. Bonamente; A.W. Borgland; A. Bouvier; J. Bregeon; A. Brez; M.S. Briggs; M. Brigida; P. Bruel; R. Buehler; S. Buson; G.A. Caliandro; R.A. Cameron; P.A. Caraveo; S. Carrigan; J.M. Casandjian; C. Cecchi; O. Celik; V. Chaplin; E. Charles; A. Chekhtman; J. Chiang; S. Ciprini; R. Claus; J. Cohen-Tanugi; V. Connaughton; J. Conrad; S. Cutini; C. Dermer; A. de Angelis; F. de Palma; B. Dingus; E. do Couto e Silva; P.S. Drell; R. Dubois; C. Favuzzi; S. Fegan; E.C. Ferrara; W.B. Focke; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; N. Giglietto; N. Giordano; N. Vilchez

doi:10.1088/0004-637X/729/2/114

Detection of a spectral break in the extra hard component of GRB 090926A

M. Ackermann, M. Ajello, K. Asano, M. Axelsson, L. Baldini, J. Ballet, G. Barbiellini, M.G. Baring, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, P.N. Bhat, E. Bissaldi, R. Blandford, E. Bonamente, A.W. Borgland, A. Bouvier, J. Bregeon, A. BrezM.S. Briggs, M. Brigida, P. Bruel, R. Buehler, S. Buson, G.A. Caliandro, R.A. Cameron, P.A. Caraveo, S. Carrigan, J.M. Casandjian, C. Cecchi, O. Celik, V. Chaplin, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, V. Connaughton, J. Conrad, S. Cutini, C. Dermer, A. de Angelis, F. de Palma, B. Dingus, E. do Couto e Silva, P.S. Drell, R. Dubois, C. Favuzzi, S. Fegan, E.C. Ferrara, W.B. Focke, M. Frailis, Y. Fukazawa, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, N. Gehrels, N. Giglietto, N. Giordano, N. Vilchez

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Abstract

We report on the observation of the bright, long gamma-ray burst,GRB 090926A, by the Gamma-ray Burst Monitor (GBM) and Large Area Tele-scope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other GRBs, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

Original language	English
Journal	The Astrophysical Journal
Volume	729
Issue number	2
DOIs	https://doi.org/10.1088/0004-637X/729/2/114
Publication status	Published - 2011

Keywords

gamma rays: bursts

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Ackermann, M., Ajello, M., Asano, K., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Bhat, P. N., Bissaldi, E., Blandford, R., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., ... Vilchez, N. (2011). Detection of a spectral break in the extra hard component of GRB 090926A. The Astrophysical Journal, 729(2). https://doi.org/10.1088/0004-637X/729/2/114

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title = "Detection of a spectral break in the extra hard component of GRB 090926A",

abstract = "We report on the observation of the bright, long gamma-ray burst,GRB 090926A, by the Gamma-ray Burst Monitor (GBM) and Large Area Tele-scope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other GRBs, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.",

keywords = "gamma rays: bursts",

author = "M. Ackermann and M. Ajello and K. Asano and M. Axelsson and L. Baldini and J. Ballet and G. Barbiellini and M.G. Baring and D. Bastieri and K. Bechtol and R. Bellazzini and B. Berenji and P.N. Bhat and E. Bissaldi and R. Blandford and E. Bonamente and A.W. Borgland and A. Bouvier and J. Bregeon and A. Brez and M.S. Briggs and M. Brigida and P. Bruel and R. Buehler and S. Buson and G.A. Caliandro and R.A. Cameron and P.A. Caraveo and S. Carrigan and J.M. Casandjian and C. Cecchi and O. Celik and V. Chaplin and E. Charles and A. Chekhtman and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and V. Connaughton and J. Conrad and S. Cutini and C. Dermer and \{de Angelis\}, A. and \{de Palma\}, F. and B. Dingus and \{do Couto e Silva\}, E. and P.S. Drell and R. Dubois and C. Favuzzi and S. Fegan and E.C. Ferrara and W.B. Focke and M. Frailis and Y. Fukazawa and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and N. Gehrels and N. Giglietto and N. Giordano and N. Vilchez",

note = "{\textquoteleft}In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.{\textquoteright} Original article can be found at: http://iopscience.iop.org/ Copyright American Astronomical Society",

year = "2011",

doi = "10.1088/0004-637X/729/2/114",

language = "English",

volume = "729",

journal = "The Astrophysical Journal",

issn = "0004-637X",

publisher = "American Astronomical Society",

number = "2",

}

Ackermann, M, Ajello, M, Asano, K, Axelsson, M, Baldini, L, Ballet, J, Barbiellini, G, Baring, MG, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Bhat, PN, Bissaldi, E, Blandford, R, Bonamente, E, Borgland, AW, Bouvier, A, Bregeon, J, Brez, A, Briggs, MS, Brigida, M, Bruel, P, Buehler, R, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Carrigan, S, Casandjian, JM, Cecchi, C, Celik, O, Chaplin, V, Charles, E, Chekhtman, A, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Connaughton, V, Conrad, J, Cutini, S, Dermer, C, de Angelis, A, de Palma, F, Dingus, B, do Couto e Silva, E, Drell, PS, Dubois, R, Favuzzi, C, Fegan, S, Ferrara, EC, Focke, WB, Frailis, M, Fukazawa, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Gehrels, N, Giglietto, N, Giordano, N & Vilchez, N 2011, 'Detection of a spectral break in the extra hard component of GRB 090926A', The Astrophysical Journal, vol. 729, no. 2. https://doi.org/10.1088/0004-637X/729/2/114

TY - JOUR

T1 - Detection of a spectral break in the extra hard component of GRB 090926A

AU - Ackermann, M.

AU - Ajello, M.

AU - Asano, K.

AU - Axelsson, M.

AU - Baldini, L.

AU - Ballet, J.

AU - Barbiellini, G.

AU - Baring, M.G.

AU - Bastieri, D.

AU - Bechtol, K.

AU - Bellazzini, R.

AU - Berenji, B.

AU - Bhat, P.N.

AU - Bissaldi, E.

AU - Blandford, R.

AU - Bonamente, E.

AU - Borgland, A.W.

AU - Bouvier, A.

AU - Bregeon, J.

AU - Brez, A.

AU - Briggs, M.S.

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 - Carrigan, S.

AU - Casandjian, J.M.

AU - Cecchi, C.

AU - Celik, O.

AU - Chaplin, V.

AU - Charles, E.

AU - Chekhtman, A.

AU - Chiang, J.

AU - Ciprini, S.

AU - Claus, R.

AU - Cohen-Tanugi, J.

AU - Connaughton, V.

AU - Conrad, J.

AU - Cutini, S.

AU - Dermer, C.

AU - de Angelis, A.

AU - de Palma, F.

AU - Dingus, B.

AU - do Couto e Silva, E.

AU - Drell, P.S.

AU - Dubois, R.

AU - Favuzzi, C.

AU - Fegan, S.

AU - Ferrara, E.C.

AU - Focke, W.B.

AU - Frailis, M.

AU - Fukazawa, Y.

AU - Funk, S.

AU - Fusco, P.

AU - Gargano, F.

AU - Gasparrini, D.

AU - Gehrels, N.

AU - Giglietto, N.

AU - Giordano, N.

AU - Vilchez, N.

N1 - ‘In these times, during the rise in the popularity of institutional repositories, the Society does not forbid authors from depositing their work in such repositories. However, the AAS regards the deposit of scholarly work in such repositories to be a decision of the individual scholar, as long as the individual's actions respect the diligence of the journals and their reviewers.’ Original article can be found at: http://iopscience.iop.org/ Copyright American Astronomical Society

PY - 2011

Y1 - 2011

N2 - We report on the observation of the bright, long gamma-ray burst,GRB 090926A, by the Gamma-ray Burst Monitor (GBM) and Large Area Tele-scope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other GRBs, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

AB - We report on the observation of the bright, long gamma-ray burst,GRB 090926A, by the Gamma-ray Burst Monitor (GBM) and Large Area Tele-scope (LAT) instruments on board the Fermi Gamma-ray Space Telescope. GRB 090926A shares several features with other bright LAT bursts. In particular, it clearly shows a short spike in the light curve that is present in all detectors that see the burst, and this in turn suggests that there is a common region of emission across the entire Fermi energy range. In addition, while a separate high-energy power-law component has already been observed in other GRBs, here we report for the first time the detection with good significance of a high-energy spectral break (or cutoff) in this power-law component around 1.4 GeV in the time-integrated spectrum. If the spectral break is caused by opacity to electron-positron pair production within the source, then this observation allows us to compute the bulk Lorentz factor for the outflow, rather than a lower limit.

KW - gamma rays: bursts

U2 - 10.1088/0004-637X/729/2/114

DO - 10.1088/0004-637X/729/2/114

M3 - Article

SN - 0004-637X

VL - 729

JO - The Astrophysical Journal

JF - The Astrophysical Journal

IS - 2

ER -

Detection of a spectral break in the extra hard component of GRB 090926A

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Keywords

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