Skip to main content
OSTI.GOVU.S. Department of Energy Office of Scientific and Technical Information
U.S. Department of Energy
Office of Scientific and Technical Information
 

Fermi -LAT Observations of High-energy Behind-the-limb Solar Flares

Journal Article · · Astrophysical Journal
;  [1]; ; ; ;  [2];  [3];  [4];  [5];  [6]; ; ;  [7];  [8];  [9];  [10];  [11]; ;  [12];
  1. Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany)
  2. W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)
  3. Università di Pisa and Istituto Nazionale di Fisica Nucleare, Sezione di Pisa I-56127 Pisa (Italy)
  4. Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy)
  5. Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy)
  6. Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy)
  7. Istituto Nazionale di Fisica Nucleare, Sezione di Bari, I-70126 Bari (Italy)
  8. Istituto Nazionale di Fisica Nucleare, Sezione di Torino, I-10125 Torino (Italy)
  9. Laboratoire Univers et Particules de Montpellier, Université Montpellier, CNRS/IN2P3, F-34095 Montpellier (France)
  10. Laboratoire Leprince-Ringuet, École polytechnique, CNRS/IN2P3, F-91128 Palaiseau (France)
  11. INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133 Milano (Italy)
  12. Agenzia Spaziale Italiana (ASI) Science Data Center, I-00133 Roma (Italy)
+ Show Author Affiliations

We report on the Fermi -LAT detection of high-energy emission from the behind-the-limb (BTL) solar flares that occurred on 2013 October 11, and 2014 January 6 and September 1. The Fermi -LAT observations are associated with flares from active regions originating behind both the eastern and western limbs, as determined by STEREO . All three flares are associated with very fast coronal mass ejections (CMEs) and strong solar energetic particle events. We present updated localizations of the >100 MeV photon emission, hard X-ray (HXR) and EUV images, and broadband spectra from 10 keV to 10 GeV, as well as microwave spectra. We also provide a comparison of the BTL flares detected by Fermi -LAT with three on-disk flares and present a study of some of the significant quantities of these flares as an attempt to better understand the acceleration mechanisms at work during these occulted flares. We interpret the HXR emission to be due to electron bremsstrahlung from a coronal thin-target loop top with the accelerated electron spectra steepening at semirelativistic energies. The >100 MeV gamma-rays are best described by a pion-decay model resulting from the interaction of protons (and other ions) in a thick-target photospheric source. The protons are believed to have been accelerated (to energies >10 GeV) in the CME environment and precipitate down to the photosphere from the downstream side of the CME shock and landed on the front side of the Sun, away from the original flare site and the HXR emission.

OSTI ID:
22663918
Journal Information:
Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 835; ISSN ASJOAB; ISSN 0004-637X
Country of Publication:
United States
Language:
English

Cited By (36)

Characteristics of Late-phase >100 MeV Gamma-Ray Emission in Solar Eruptive Events journal December 2018
Implications of a Loop-top Origin for Microwave, Hard X-Ray, and Low-energy Gamma-Ray Emission from Behind-the-limb Flares journal September 2018
Electron Power-Law Spectra in Solar and Space Plasmas journal June 2018
A Statistical Study to Determine the Origin of Long-duration Gamma-Ray Flares journal August 2018
Investigating the Origins of Two Extreme Solar Particle Events: Proton Source Profile and Associated Electromagnetic Emissions journal April 2017
A Statistical Study to Determine the Origin of Long-Duration Gamma-ray Flares text January 2018
The Disappearing Solar Filament of 2013 September 29 and Its Large Associated Proton Event: Implications for Particle Acceleration at the Sun journal May 2019
Multiscale Time- and Frequency-domain Likelihood Analysis with Photon Weights journal November 2019
Unexpected dip in the solar gamma-ray spectrum journal September 2018
On the expected γ-ray emission from nearby flaring stars journal October 2017
Gamma-ray Flux Distribution and Non-linear behavior of Four LAT Bright AGNs text January 2017
The Relationship between Long-Duration Gamma-Ray Flares and Solar Cosmic Rays journal July 2017
Interplanetary Protons versus Interacting Protons in the 2017 September 10 Solar Eruptive Event journal February 2020
Multiwavelength Stereoscopic Observation of the 2013 May 1 Solar Flare and CME journal November 2019
The Relation between Escape and Scattering Times of Energetic Particles in a Turbulent Magnetized Plasma: Application to Solar Flares journal November 2018
Implications of loop-top origin for microwave, hard X-ray, and low-energy gamma-ray emissions from behind the limb flares text January 2018
The Relationship between Long-Duration Gamma-Ray Flares and Solar Cosmic Rays text January 2017
Source of Energetic Protons in the 2014 September 1 Sustained Gamma-ray Emission Event journal February 2020
Gamma-Ray Flux Distribution and Nonlinear Behavior of Four LAT Bright AGNs journal November 2017
On the Link between the Release of Solar Energetic Particles Measured at Widespread Heliolongitudes and the Properties of the Associated Coronal Shocks journal September 2017
Radio, Hard X-Ray, and Gamma-Ray Emissions Associated with a Far-Side Solar Event journal October 2018
Multiwavelength Stereoscopic Observation of the May 1, 2013 Solar Flare and CME text January 2020
Magnetic Flux Reconnection in Flaring Active Regions with Sustained Gamma-Ray Emission journal November 2018
Electron Power-Law Spectra in Solar and Space Plasmas text January 2018
Comparing Long-duration Gamma-Ray Flares and High-energy Solar Energetic Particles journal July 2019
Gamma-Ray Solar Flares and In Situ Particle Acceleration journal July 2017
On the Shock Source of Sustained Gamma-Ray Emission from the Sun journal November 2019
On the Shock Source of Sustained Gamma-Ray Emission from the Sun text January 2019
Radio Astronomical Tools for the Study of Solar Energetic Particles II.Time-Extended Acceleration at Subrelativistic and Relativistic Energies journal March 2021
Unexpected Dip in the Solar Gamma-Ray Spectrum text January 2018
Estimation of a coronal mass ejection magnetic field strength using radio observations of gyrosynchrotron radiation journal December 2017
Estimation of a Coronal Mass Ejection Magnetic Field Strength using Radio Observations of Gyrosynchrotron Radiation text January 2017
Source Energy Spectrum of the 17 May 2012 GLE journal May 2018
Comparing Long-Duration Gamma-Ray Flares and High-Energy Solar Energetic Particles text January 2019
Fermi -LAT Observations of the 2017 September 10 Solar Flare journal September 2018
On the expected $\gamma$-ray emission from nearby flaring stars text January 2017

Similar Records

Fermi-LAT Observations of High-energy Behind-the-limb Solar Flares
Journal Article · Mon Jan 30 23:00:00 EST 2017 · The Astrophysical Journal (Online) · OSTI ID:1355739
The Coupling of an EUV Coronal Wave and Ion Acceleration in a Fermi-LAT Behind-the-Limb Solar Flare
Journal Article · Wed Apr 27 00:00:00 EDT 2022 · The Astrophysical Journal · OSTI ID:1872398
FIRST DETECTION OF >100 MeV GAMMA-RAYS ASSOCIATED WITH A BEHIND-THE-LIMB SOLAR FLARE
Journal Article · Mon Jun 01 00:00:00 EDT 2015 · Astrophysical Journal Letters · OSTI ID:22518967

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCELERATION
BREMSSTRAHLUNG
COMPARATIVE EVALUATIONS
DETECTION
ELECTRON SPECTRA
GAMMA RADIATION
GEV RANGE
HARD X RADIATION
INTERACTIONS
LIMBS
MASS
MEV RANGE
MICROWAVE RADIATION
MICROWAVE SPECTRA
PHOTON EMISSION
PHOTONS
PHOTOSPHERE
PROTONS
SOLAR FLARES
SUN