Interpretations and implications of y-ray lines from solar flares, the galactic centre and y-ray transients

1981 ◽  
Vol 301 (1462) ◽  
pp. 671-686 ◽  
Keyword(s):  
Solar Flares ◽  
Gamma Ray ◽  
Line Emission ◽  
Galactic Centre

Observations and theories of astrophysical y-ray line emission are reviewed and prospects for future observations by the spectroscopy experiments on the planned Gamma-Ray Observatory are discussed.

Detection of y-ray lines

1981 ◽  
Vol 301 (1462) ◽  
pp. 669-669
Keyword(s):  
Solar Flares ◽  
Gamma Ray ◽  
Line Emission ◽  
Galactic Centre ◽  
Centre Region ◽  
Transient Events ◽  
Positive Results

Although detectable y-ray line emission from various astrophysical sources has been predicted for over two decades, it is only recently that positive results have been obtained. The first unambiguous extraterrestrial lines were from the great solar flares of 2 and 4 August 1972, at 0.5, 2.2 and 4.4 MeV . Earlier reports from balloon observations of lines from the galactic centre and Cen A near 2.2, 4.4 and 6.13 MeV seem not to have been confirmed by more recent spacecraft observations. The 0.5 MeV line seems definitely to have been seen from the galactic centre region. Lines at various energies have also been detected from transient events and during cosmic y-ray bursts. Earlier limits from balloons were at 10 -3 ph cm-2 s -1 ; recent observations and limits are nearer 10 -4 ph cm -2 s -1 . The Gamma-Ray Observatory to be launched in 1985 will carry an array of cooled Ge detectors whose sensitivity will be ca. 10 -5 ph cm -2 s -1 .

scholarly journals Search for Gamma-ray Line emission from Dark Matter annihilation in the Galactic Centre with the MAGIC telescopes

2021 ◽  
Author(s):  
Tomohiro Inada ◽  
Ana Babic ◽  
Andrés Baquero ◽  
Ivana Batković ◽  
Josefa Becerra Gonzalez ◽  
...  
Keyword(s):  
Dark Matter ◽  
Gamma Ray ◽  
Line Emission ◽  
Galactic Centre ◽  
Dark Matter Annihilation

scholarly journals Gamma-ray lines and neutrons from solar flares

Solar Physics ◽  
1983 ◽  
Vol 86 (1-2) ◽  
pp. 395-408 ◽  
Author(s):  
R. Ramaty ◽  
R. J. Murphy ◽  
B. Kozlovsky ◽  
R. E. Lingenfelter
Keyword(s):  
Solar Flares ◽  
Gamma Ray

Detector and imaging systems for the gamma-ray imager/polarimeter for solar flares (GRIPS) instrument

2013 ◽  
Author(s):  
Nicole Duncan ◽  
Albert Shih ◽  
Gordon Hurford ◽  
Pascal Saint-Hilaire ◽  
Andreas Zoglauer ◽  
...  
Keyword(s):  
Solar Flares ◽  
Gamma Ray ◽  
Imaging Systems

scholarly journals Gamma-rays from Solar Flares

2000 ◽  
Vol 195 ◽  
pp. 123-132 ◽  
Author(s):  
R. Ramaty ◽  
N. Mandzhavidze
Keyword(s):  
Energy Release ◽  
Gamma Rays ◽  
Solar Flares ◽  
Gamma Ray ◽  
Particle Interaction ◽  
Mass Motion ◽  
Relativistic Electrons ◽  
Total Energy Release ◽  
Flare Energy ◽  
Accelerated Particles

Gamma-ray emission is the most direct diagnostic of energetic ions and relativistic electrons in solar flares. Analysis of solar flare gamma-ray data has shown: (i) ion acceleration is a major consequence of flare energy release, as the total flare energy in accelerated particles appears to be equipartitioned between ≳ 1 MeV/nucleon ions and ≳ 20 keV electrons, and amounts to an important fraction of the total energy release; (ii) there are flares for which over 50% of the energy is in a particles and heavier ions; (iii) in both impulsive and gradual flares, the particles that interact at the Sun and produce gamma rays are essentially always accelerated by the same mechanism that operates in impulsive flares, probably stochastic acceleration through gyroresonant wave particle interaction; and (iv) gamma-ray spectroscopy can provide new information on solar abundances, for example the site of the FIP-bias onset and the photospheric 3He abundance. We propose a new technique for the investigation of mass motion and mixing in the solar atmosphere: the observations of gamma-ray lines from long-term radioactivity produced by flare accelerated particles.

The gamma-ray line emission of Orion

1998 ◽  
Author(s):  
Michel Cassé ◽  
Elisabeth Vangioni-Flam ◽  
Sean T. Scully
Keyword(s):  
Gamma Ray ◽  
Line Emission

Is the Galactic Centre gamma-ray source 1E1740.7 – 2942 accreting from a molecular cloud?

Nature ◽  
1991 ◽  
Vol 353 (6341) ◽  
pp. 234-237 ◽  
Author(s):  
John Bally ◽  
Marvin Leventhal
Keyword(s):  
Molecular Cloud ◽  
Gamma Ray ◽  
Galactic Centre

scholarly journals LIGHT SUPERCONDUCTING STRINGS IN THE GALAXY

2007 ◽  
Vol 16 (12b) ◽  
pp. 2399-2405 ◽  
Author(s):  
FRANCESC FERRER ◽  
TANMAY VACHASPATI
Keyword(s):  
Magnetic Field ◽  
Spatial Distribution ◽  
Particle Physics ◽  
Milky Way ◽  
Gamma Ray ◽  
Galactic Center ◽  
Line Emission ◽  
Galactic Magnetic Field ◽  
The Galaxy ◽  
Intense Source

Observations of the Milky Way by the SPI/INTEGRAL satellite have confirmed the presence of a strong 511 keV gamma ray line emission from the bulge, which requires an intense source of positrons in the galactic center. These observations are hard to account for by conventional astrophysical scenarios, whereas other proposals, such as light DM, face stringent constraints from the diffuse gamma ray background. Here we suggest that light superconducting strings could be the source of the observed 511 keV emission. The associated particle physics, at the ~ 1 TeV scale, is within the reach of planned accelerator experiments, while the distinguishing spatial distribution, proportional to the galactic magnetic field, could be mapped by SPI or by future, more sensitive satellite missions.

scholarly journals De-Excitation Gamma-ray Line Emission from the Galactic Center

2010 ◽  
Author(s):  
Dmitry Chernyshov ◽  
V. A. Dogiel ◽  
V. Tatischeff ◽  
Kwong-Sang Cheng ◽  
Chung-Ming Ko ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Galactic Center ◽  
Line Emission
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