Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares

Marco Ajello; A. Albert; A. Allafort; Luca Baldini; Guido Barbiellini; D. Bastieri; R. Bellazzini; E. Bissaldi; E. Bonamente; T. J. Brandt; J. Bregeon; M. Brigida; Pascal Bruel; R. Buehler; S. Buson; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; C. Cecchi; E. Charles; A. Chekhtman; J. Chiang; G. Chiaro; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; F. d'Ammando; F. de Palma; C. D. Dermer; E. Do Couto E Silva; P. S. Drell; A. Drlica-Wagner; C. Favuzzi; W. B. Focke; A. Franckowiak; Y. Fukazawa; F. Gargano; D. Gasparrini; S. Germani; N. Giglietto; P. Giommi; F. Giordano; M. Giroletti; T. Glanzman; G. Godfrey; J. E. Grove; D. Hadasch; M. Hayashida; D. Horan; Y. Inoue; M. S. Jackson; T. Jogler; G.J ́ Ohannesson; Jürgen Knödlseder; D. Kocevski; L. Latronico; F. Loparco; N. Lovellette; P. Lubrano; M. Mayer; M. N. Mazziotta; P. F. Michelson; T. Mizuno; A. A. Moiseev; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; R. Murphy; T. Nakamori; R. Nemmen; M. Ohno; T. Ohsugi; N. Omodei; M. Orienti; E. Orlando; D. Paneque; J. H. Panetta; J. S. Perkins; M. Pesce-Rollins; V. Petrosian; F. Piron; G. Pivato; T.A. Porter; S. Rain ' O; R. Rando; M. Razzano; M. Roth; A. Schulz; C. Sgro; G. Spandre; P. Spinelli; H. Takahashi; J. G. Thayer; J. B. Thayer; D. J. Thompson; L. Tibaldo; M. Tinivella; G. Tosti; J. Vandenbroucke; V. Vasileiou; G. Vianello; V. Vitale; M. Werner; Z. Yang; X. Hou; B. Lott; E. Nuss

doi:10.1088/0004-637X/789/1/20

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Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares

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Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares

Marco Ajello, A. Albert, A. Allafort, Luca Baldini, Guido Barbiellini, D. Bastieri, R. Bellazzini, E. Bissaldi, E. Bonamente, T. J. Brandt, …

The Astrophysical Journal, Vol.789

2014

DOI: https://doi.org/10.1088/0004-637X/789/1/20

Abstract

Sun: X-rays

Sun: flares

gamma rays

The Fermi Large Area Telescope (LAT) observed two bright X-class solar ares on 2012 March 7, and detected gamma-rays up to 4 GeV. We detected gamma-rays both during the impulsive and temporally-extended emission phases, with emission above 100 MeV lasting for approximately 20 hours. Accurate localization of the gamma-ray production site(s) coincide with the solar active region from which X-ray emissions associated with these ares originated. Our analysis of the > 100 MeV gamma-ray emission shows a relatively rapid monotonic decrease in ux during the rst hour of the impulsive phase, and a much slower, almost monotonic decrease in ux for the next 20 hours. The spectra can be adequately described by a power law with a high energy exponential cuto , or as resulting from the decay of neutral pions produced by accelerated protons and ions with an isotropic power-law energy distribution. The required proton spectrum has a number index 3, with minor variations during the impulsive phase, while during the temporally extended phase the spectrum softens monotonically, starting with index 4. The > 30 MeV proton ux and spectra observed near the Earth by the GOES satellites also show a monotonic ux decrease and spectral softening during the extended phase, but with a harder spectrum, with index 3. Based on the Fermi -LAT and GOES observations of the ux and spectral evolution of these bright ares, we explore the relative merits of prompt and continuous acceleration scenarios, hadronic and leptonic emission processes, and acceleration at the solar corona by the fast Coronal Mass Ejections (CME) as explanations for the observations. We conclude that the most likely scenario is continuous acceleration of protons in the solar corona which penetrate the lower solar atmosphere and produce pions that decay into gamma-rays.

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Title: Impulsive and Long Duration High-Energy Gamma-ray Emission From the Very Bright 2012 March 7 Solar Flares
Creators - without role: Marco Ajello - University of California, Berkeley
A. Albert - Kavli Institute for Particle Astrophysics and Cosmology
A. Allafort - Kavli Institute for Particle Astrophysics and Cosmology
Luca Baldini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
Guido Barbiellini - University of Trieste
D. Bastieri - University of Padua
R. Bellazzini - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
E. Bissaldi - Istituto Nazionale di Fisica Nucleare, Sezione di Trieste
E. Bonamente - University of Perugia
T. J. Brandt
J. Bregeon - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Brigida - Polytechnic University of Bari
Pascal Bruel - École Polytechnique
R. Buehler - Deutsches Elektronen-Synchrotron DESY
S. Buson - University of Padua
G. A. Caliandro
R. A. Cameron
P. A. Caraveo - Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano
C. Cecchi - University of Perugia
E. Charles - Kavli Institute for Particle Astrophysics and Cosmology
A. Chekhtman - George Mason University
J. Chiang - Kavli Institute for Particle Astrophysics and Cosmology
G. Chiaro - University of Padua
S. Ciprini - Agenzia Spaziale Italiana
R. Claus - Kavli Institute for Particle Astrophysics and Cosmology
J. Cohen-Tanugi - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
J. Conrad - AlbaNova
F. d'Ammando
F. de Palma - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
C. D. Dermer
E. Do Couto E Silva
P. S. Drell
A. Drlica-Wagner - Fermi National Accelerator Laboratory
C. Favuzzi - Polytechnic University of Bari
W. B. Focke
A. Franckowiak - Kavli Institute for Particle Astrophysics and Cosmology
Y. Fukazawa - Hiroshima University
F. Gargano - Istituto Nazionale di Fisica Nucleare, Sezione di Bari
D. Gasparrini - Agenzia Spaziale Italiana
S. Germani - University of Perugia
N. Giglietto - Polytechnic University of Bari
P. Giommi - Agenzia Spaziale Italiana
F. Giordano - Polytechnic University of Bari
M. Giroletti - Istituto di Radioastronomia di Bologna
T. Glanzman - Stanford University
G. Godfrey - Kavli Institute for Particle Astrophysics and Cosmology
J. E. Grove
D. Hadasch - Universität Innsbruck
M. Hayashida - The University of Tokyo
D. Horan - Laboratoire Leprince-Ringuet
Y. Inoue - Stanford University
M. S. Jackson
T. Jogler - Stanford University
G.J ́ Ohannesson
Jürgen Knödlseder - Centre National de la Recherche Scientifique
D. Kocevski - Stanford University
L. Latronico - Istituto Nazionale di Fisica Nucleare, Sezione di Torino
F. Loparco - Polytechnic University of Bari
N. Lovellette
P. Lubrano - University of Perugia
M. Mayer - Deutsches Elektronen-Synchrotron DESY
M. N. Mazziotta
P. F. Michelson
T. Mizuno - Hiroshima University
A. A. Moiseev
M. E. Monzani
A. Morselli - Istituto Nazionale di Fisica Nucleare, Roma Tor Vergata
I. V. Moskalenko
S. Murgia - University of California, Irvine
R. Murphy - United States Naval Research Laboratory
T. Nakamori
R. Nemmen - Goddard Space Flight Center
M. Ohno - Hiroshima University
T. Ohsugi - Hiroshima University
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
D. Paneque - Kavli Institute for Particle Astrophysics and Cosmology
J. H. Panetta
J. S. Perkins
M. Pesce-Rollins - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
V. Petrosian - Stanford University
F. Piron - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
G. Pivato - University of Padua
T.A. Porter - Kavli Institute for Particle Astrophysics and Cosmology
S. Rain ' O
R. Rando - University of Padua
M. Razzano - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
M. Roth - University of Washington
A. Schulz - Deutsches Elektronen-Synchrotron DESY
C. Sgro - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
G. Spandre - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
P. Spinelli - Polytechnic University of Bari
H. Takahashi - Hiroshima University
J. G. Thayer
J. B. Thayer
D. J. Thompson
L. Tibaldo - Kavli Institute for Particle Astrophysics and Cosmology
M. Tinivella - Istituto Nazionale di Fisica Nucleare, Sezione di Pisa
G. Tosti - University of Perugia
J. Vandenbroucke - Kavli Institute for Particle Astrophysics and Cosmology
V. Vasileiou - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
G. Vianello - Consorzio Interuniversitario Fisica Spaziale
V. Vitale - University of Rome Tor Vergata
M. Werner - Universität Innsbruck
Z. Yang - AlbaNova
X. Hou - Laboratoire de Physique des deux infinis Bordeaux
B. Lott - Centre National de la Recherche Scientifique
E. Nuss - Université de Montpellier, Laboratoire Univers et Particules de Montpellier - LUPM
Publication Details: The Astrophysical Journal, Vol.789
Identifiers: 9935369009311
Academic Unit: Laboratoire Univers et Particules de Montpellier - LUPM
Language: English
Resource Type: Journal article
Local Fields: in2p3-01071503