Investigating the nature of late-time high-energy GRB emission through joint Fermi/Swift observations

M. Ajello; L. Baldini; G. Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; R.D. Blandford; R. Bonino; E. Bottacini; J. Bregeon; P. Bruel; R. Buehler; R.A. Cameron; R. Caputo; P.A. Caraveo; G. Chiaro; S. Ciprini; Johann Cohen-Tanugi; D. Costantin; F. d'Ammando; F. de Palma; N. Di Lalla; M. Di Mauro; L. Di Venere; A. Domínguez; C. Favuzzi; A. Franckowiak; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Giglietto; F. Giordano; M. Giroletti; D. Green; I.A. Grenier; S. Guiriec; C. Holt; D. Horan; G. Jóhannesson; D. Kocevski; M. Kuss; G.La Mura; S. Larsson; J. Li; F. Longo; F. Loparco; P. Lubrano; J.D. Magill; S. Maldera; A. Manfreda; M.N. Mazziotta; P.F. Michelson; T. Mizuno; M.E. Monzani; A. Morselli; M. Negro; E. Nuss; N. Omodei; M. Orienti; E. Orlando; V.S. Paliya; J.S. Perkins; M. Persic; M. Pesce-Rollins; F. Piron; G. Principe; J.L. Racusin; S. Rainò; R. Rando; M. Razzano; S. Razzaque; A. Reimer; O. Reimer; C. Sgrò; E.J. Siskind; G. Spandre; P. Spinelli; D. Tak; J.B. Thayer; D.F. Torres; G. Tosti; J. Valverde; M. Vogel; K. Wood

doi:10.3847/1538-4357/aad000

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Investigating the nature of late-time high-energy GRB emission through joint Fermi/Swift observations

Journal article

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Investigating the nature of late-time high-energy GRB emission through joint Fermi/Swift observations

M. Ajello, L. Baldini, G. Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, R.D. Blandford, R. Bonino, E. Bottacini, J. Bregeon, …

The Astrophysical Journal, Vol.863(2)

2018

DOI: https://doi.org/10.3847/1538-4357/aad000

Abstract

GLAST

flux

gamma-ray burst: general

gamma ray: burst

X-ray: emission

energy: density

energy: high

X-ray: detector

electron: relativistic

electron: spectrum

electron synchrotron

Compton scattering

synchrotron

magnetic field

long-lived

spectral

We use joint observations by the Swift X-ray Telescope (XRT) and the Fermi Large Area Telescope (LAT) of gamma-ray burst (GRB) afterglows to investigate the nature of the long-lived high-energy emission observed by Fermi LAT. Joint broadband spectral modeling of XRT and LAT data reveals that LAT nondetections of bright X-ray afterglows are consistent with a cooling break in the inferred electron synchrotron spectrum below the LAT and/or XRT energy ranges. Such a break is sufficient to suppress the high-energy emission so as to be below the LAT detection threshold. By contrast, LAT-detected bursts are best fit by a synchrotron spectrum with a cooling break that lies either between or above the XRT and LAT energy ranges. We speculate that the primary difference between GRBs with LAT afterglow detections and the nondetected population may be in the type of circumstellar environment in which these bursts occur, with late-time LAT detections preferentially selecting GRBs that occur in low wind-like circumburst density profiles. Furthermore, we find no evidence of high-energy emission in the LAT-detected population significantly in excess of the flux expected from the electron synchrotron spectrum fit to the observed X-ray emission. The lack of excess emission at high energies could be due to a shocked external medium in which the energy density in the magnetic field is stronger than or comparable to that of the relativistic electrons behind the shock, precluding the production of a dominant synchrotron self-Compton (SSC) component in the LAT energy range. Alternatively, the peak of the SSC emission could be beyond the 0.1–100 GeV energy range considered for this analysis.

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Title: Investigating the nature of late-time high-energy GRB emission through joint Fermi/Swift observations
Creators - without role: M. Ajello - Clemson University
L. Baldini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
G. Barbiellini - University of Trieste
D. Bastieri - University of Padua
R. Bellazzini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
E. Bissaldi - Polytechnic University of Bari
R.D. Blandford - Kavli Institute for Particle Astrophysics and Cosmology
R. Bonino - University of Turin
E. Bottacini - SLAC National Accelerator Laboratory
J. Bregeon - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
P. Bruel - École Polytechnique
R. Buehler - Deutsches Elektronen-Synchrotron DESY
R.A. Cameron - Stanford University
R. Caputo - Goddard Space Flight Center
P.A. Caraveo - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
G. Chiaro - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
S. Ciprini - Istituto Nazionale di Fisica Nucleare, Sezione di Perugia
Johann Cohen-Tanugi - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
D. Costantin - University of Padua
F. d'Ammando
F. de Palma - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
N. Di Lalla - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Di Mauro - Kavli Institute for Particle Astrophysics and Cosmology
L. Di Venere - Polytechnic University of Bari
A. Domínguez - Universidad Complutense de Madrid
C. Favuzzi - Polytechnic University of Bari
A. Franckowiak - Deutsches Elektronen-Synchrotron DESY
Y. Fukazawa - Hiroshima University
S. Funk - Friedrich-Alexander-Universität Erlangen-Nürnberg
P. Fusco - Polytechnic University of Bari
F. Gargano - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
D. Gasparrini - Agenzia Spaziale Italiana
N. Giglietto - Polytechnic University of Bari
F. Giordano - Polytechnic University of Bari
M. Giroletti - Istituto di Radioastronomia di Bologna
D. Green - Goddard Space Flight Center
I.A. Grenier - CEA Paris-Saclay
S. Guiriec - George Washington University
C. Holt - University of Maryland, Baltimore County
D. Horan - Laboratoire Leprince-Ringuet
G. Jóhannesson - Nordic Institute for Theoretical Physics
D. Kocevski - Goddard Space Flight Center
M. Kuss - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
G.La Mura
S. Larsson - AlbaNova
J. Li - Institute of Space Sciences
F. Longo - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
F. Loparco - Polytechnic University of Bari
P. Lubrano - Istituto Nazionale di Fisica Nucleare, Sezione di Perugia
J.D. Magill - University of Maryland, College Park
S. Maldera - Istituto Nazionale di Fisica Nucleare, Sezione di Torino
A. Manfreda - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M.N. Mazziotta - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
P.F. Michelson - Kavli Institute for Particle Astrophysics and Cosmology
T. Mizuno - Hiroshima University
M.E. Monzani - Kavli Institute for Particle Astrophysics and Cosmology
A. Morselli - Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata
M. Negro - Istituto Nazionale di Fisica Nucleare, Sezione di Torino
E. Nuss - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
N. Omodei - Kavli Institute for Particle Astrophysics and Cosmology
M. Orienti - Istituto di Radioastronomia di Bologna
E. Orlando - Kavli Institute for Particle Astrophysics and Cosmology
V.S. Paliya - Clemson University
J.S. Perkins - Goddard Space Flight Center
M. Persic - Trieste Astronomical Observatory
M. Pesce-Rollins - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
F. Piron - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
G. Principe - Friedrich-Alexander-Universität Erlangen-Nürnberg
J.L. Racusin - Goddard Space Flight Center
S. Rainò - Polytechnic University of Bari
R. Rando - University of Padua
M. Razzano - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
S. Razzaque - University of Johannesburg
A. Reimer - Kavli Institute for Particle Astrophysics and Cosmology
O. Reimer - SLAC National Accelerator Laboratory
C. Sgrò - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
E.J. Siskind - Real Time Tomography
G. Spandre - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. Spinelli - Polytechnic University of Bari
D. Tak - University of Maryland, College Park
J.B. Thayer - Stanford University
D.F. Torres - Institute of Space Sciences
G. Tosti - Istituto Nazionale di Fisica Nucleare, Sezione di Perugia
J. Valverde - École Polytechnique
M. Vogel - California State University Los Angeles
K. Wood - Praxis
Publication Details: The Astrophysical Journal, Vol.863(2)
Identifiers: 9940398209311
Academic Unit: Laboratoire Univers et Particules de Montpellier - LUPM
Language: English
Resource Type: Journal article
Local Fields: hal-01867380