Properties of the energetic particle distributions during the October 28, 2003 solar flare from INTEGRAL/SPI observations

Abstract

Analysis of spectra obtained with the gamma-ray spectrometer SPI onboard INTEGRAL of the GOES X17-class flare on October 28, 2003 is presented. In the energy range 600 keV - 8 MeV three prominent narrow lines at 2.223, 4.4 and 6.1 MeV, resulting from nuclear interactions of accelerated ions within the solar atmosphere could be observed. Time profiles of the three lines and the underlying continuum indicate distinct phases with several emission peaks and varying continuum-to-line ratio for several minutes before a smoother decay phase sets in. Due to the high-resolution Ge detectors of SPI and the exceptional intensity of the flare, detailed studies of the 4.4 and 6.1 MeV line shapes was possible for the first time. Comparison with calculated line shapes using a thick target interaction model and several energetic particle angular distributions indicates that the nuclear interactions were induced by downward-directed particle beams with alpha-to-proton ratios of the order of 0.1. There are also indications that the 4.4 MeV to 6.1 MeV line fluence ratio changed between the beginning and the decay phase of the flare, possibly due to a temporal evolution of the energetic particle alpha-to-proton ratio.

24 pages, 10 figures, accepted for publication by A&A

References in corpus (5)

• The INTEGRAL IBIS/ISGRI System Point Spread Function and Source Location Accuracy
• High-Resolution Spectroscopy of Gamma-Ray Lines from the X-Class Solar Flare of 23 July, 2002
• MGGPOD: a Monte Carlo Suite for Modeling Instrumental Line and Continuum Backgrounds in Gamma-Ray Astronomy
• Directionality of Solar Flare Accelerated Protons and Alpha Particles from Gamma-Ray Line Measurements
• Shape of the 4.438 MeV gamma-ray line of ^12C from proton and alpha-particle induced reactions on ^12C and ^16O

Cited by in corpus (27)

• Global Energetics of Thirty-Eight Large Solar Eruptive Events
• Properties of Energetic Ions in the Solar Atmosphere from γ -Ray and Neutron Observations
• On the origin of 3 seismic sources in the proton-rich flare of October 28, 2003
• Nuclear-Astrophysics Lessons from INTEGRAL
• Analysis of a global Moreton wave observed on October 28, 2003
• Flare magnetic reconnection and relativistic particles in the 2003 October 28 event
• Diffuse Galactic emission spectrum between 0.5 and 8.0 MeV
• Delayed X- and Gamma-Ray Line Emission from Solar Flare Radioactivity
• A Comprehensive Search for Gamma-Ray Lines in the First Year of Data from the INTEGRAL Spectrometer
• Gamma-Ray Observations of Nova Sgr 2015 No. 2 with INTEGRAL
• Measurements of nuclear $\gamma$-ray line emission in interactions of protons and $\alpha$ particles with N, O, Ne and Si
• Recent results in nuclear astrophysics
• Nuclear Interaction Gamma-Ray Lines from the Galactic Center Region
• Non-Thermal "Burst-on-Tail" of Long-Duration Solar Event on 26 October 2003
• An unexpected outburst from A0535+262
• High resolution gamma ray spectroscopy of flares on the east and west limbs of the Sun
• Shape and angular distribution of the 4.438-MeV line from proton inelastic scattering off 12C
• Shape and Angular Distribution of the 4.438-MeV Line from Proton Inelastic Scattering off 12C
• New insights into the proton precipitation sites in solar flares
• Exploring the capabilities of the Anti-Coincidence Shield of the INTEGRAL spectrometer to study solar flares
• INTEGRAL serendipitous observations of solar and terrestrial X-rays and gamma rays
• Telescope Concepts in Gamma-Ray Astronomy
• CORONAS-F observation of gamma-ray emission from the solar flare on 2003 October 29
• Gamma-ray emission in proton-induced nuclear reactions on natC and Mylar targets over the incident energy range of Ep = 30-200 MeV. Astrophysical implications
• Line profile of nuclear de-excitation gamma-ray emission from very hot plasma
• New estimation of non-thermal electron energetics in the giant solar flare on 28 October 2003 based on Mars Odyssey observations
• Coupling between magnetic reconnection, energy release, and particle acceleration in the X17.2 2003 October 28 solar flare