scholarly journals Gamma-ray line measurements from supernova explosions

2017 ◽  
Vol 12 (S331) ◽  
pp. 157-163 ◽  
Author(s):  
Roland Diehl
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Radioactive Decay ◽  
Line Emission ◽  
Gamma Ray Spectrometry ◽  
Young Supernova Remnant ◽  
Supernova Explosions ◽  
Cas A ◽  
Integral Data ◽  
Gamma Ray Telescopes

AbstractGamma ray lines are expected to be emitted as part of the afterglow of supernova explosions, because radioactive decay of freshly synthesised nuclei occurs. Significant radioactive gamma ray line emission is expected from56Ni and44Ti decay on time scales of the initial explosion (56Ni, τ ~days) and the young supernova remnant (44Ti,τ ~90 years). Less specific, and rather informative for the supernova population as a whole, are lessons from longer lived isotopes such as26Al and60Fe. From isotopes of elements heavier than iron group elements, any interesting gamma-ray line emission is too faint to be observable. Measurements with space-based gamma-ray telescopes have obtained interesting gamma ray line emissions from two core collapse events, Cas A and SN1987A, and one thermonuclear event, SN2014J. We discuss INTEGRAL data from all above isotopes, including all line and continuum signatures from these two objects, and the surveys for more supernovae, that have been performed by gamma ray spectrometry. Our objective here is to illustrate what can be learned from gamma-ray line emission properties about the explosions and their astrophysics.

scholarly journals Nucleosynthesis in exploding massive Wolf-Rayet stars

1988 ◽  
Vol 108 ◽  
pp. 440-441 ◽  
Author(s):  
M.F. El Eid ◽  
N. Langer
Keyword(s):  
Supernova Remnant ◽  
Massive Star ◽  
Young Supernova Remnant ◽  
Cas A

Recent observations of the young supernova remnant Cas A (Fesen et al., 1987) suggest an exploding Wolf-Rayet (WR) star of WNL type as a progenitor of this object. The majority of the WR stars seems to originate from massive O-stars of M > 40 M⊙. According to current investigations (Schild and Maeder, 1984; Langer, 1987; cf. also: Langer, this volume) WNL stars rank among the most massive WR stars. Hence, it is possible to assume that the stellar progenitor of Cas A was indeed a very massive star.As shown by Langer and El Eid (1986), (see also Woosley, 1986) a population I star of initially 100 M⊙ may loose enough mass during its evolution up to core He exhaustion to become a WN star of ∼ 45 M⊙, which then mainly consists of oxygen (more than 80%) synthesized during He burning.

scholarly journals Properties of gamma-ray decay lines in 3D core-collapse supernova models, with application to SN 1987A and Cas A

2020 ◽  
Vol 494 (2) ◽  
pp. 2471-2497 ◽  
Author(s):  
A Jerkstrand ◽  
A Wongwathanarat ◽  
H-T Janka ◽  
M Gabler ◽  
D Alp ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radioactive Decay ◽  
Supernova Explosion ◽  
3D Models ◽  
Core Collapse ◽  
Line Profiles ◽  
Sn 1987A ◽  
And Shifts ◽  
Cas A ◽  
Explosive Burning

ABSTRACT Comparison of theoretical line profiles to observations provides important tests for supernova explosion models. We study the shapes of radioactive decay lines predicted by current 3D core-collapse explosion simulations, and compare these to observations of SN 1987A and Cas A. Both the widths and shifts of decay lines vary by several thousand kilometres per second depending on viewing angle. The line profiles can be complex with multiple peaks. By combining observational constraints from 56Co decay lines, 44Ti decay lines, and Fe IR lines, we delineate a picture of the morphology of the explosive burning ashes in SN 1987A. For MZAMS = 15−20 M⊙ progenitors exploding with ∼1.5 × 1051 erg, ejecta structures suitable to reproduce the observations involve a bulk asymmetry of the 56Ni of at least ∼400 km s−1 and a bulk velocity of at least 1500 km s−1. By adding constraints to reproduce the UVOIR bolometric light curve of SN 1987A up to 600 d, an ejecta mass around 14 M⊙ is favoured. We also investigate whether observed decay lines can constrain the neutron star (NS) kick velocity. The model grid provides a constraint VNS > Vredshift, and applying this to SN 1987A gives a NS kick of at least 500 km s−1. For Cas A, our single model provides a satisfactory fit to the NuSTAR observations and reinforces the result that current neutrino-driven core-collapse SN models achieve enough bulk asymmetry in the explosive burning material. Finally, we investigate the internal gamma-ray field and energy deposition, and compare the 3D models to 1D approximations.

scholarly journals 60Fe and Massive Stars

2008 ◽  
Vol 4 (S252) ◽  
pp. 333-338
Author(s):  
Wei Wang
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Massive Stars ◽  
Radioactive Decay ◽  
Line Emission ◽  
Flux Ratio ◽  
Core Collapse ◽  
Analysis Method ◽  
Line Flux ◽  
Average Flux

AbstractGamma-ray line emission from radioactive decay of 60Fe provides constraints on nucleosynthesis in massive stars and supernovae. We detect the γ-ray lines from 60Fe decay at 1173 and 1333 keV using three years of data from the spectrometer SPI on board INTEGRAL. The average flux per line is (4.4 ± 0.9) × 10−5 ph cm−2 s−1 rad−1 for the inner Galaxy region. Deriving the Galactic 26Al gamma-ray line flux with using the same set of observations and analysis method, we determine the flux ratio of 60Fe/26Al gamma-rays as 0.15 ± 0.05. We discuss the implications of these results for the widely-held hypothesis that 60Fe is synthesized in core-collapse supernovae, and also for the closely-related question of the precise origin of 26Al in massive stars.

scholarly journals Radiometric Surveys for Detection of Uranium in Dhofar Region, Sultanate of Oman

2019 ◽  
Vol 24 (1) ◽  
pp. 36
Author(s):  
Narasimman Sundararajan ◽  
Bernhard Pracejus ◽  
Salah Al- Khirbash ◽  
Talal Al-Hosni ◽  
Ala Ebrahimi Ebrahimi ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Radioactive Decay ◽  
Sampling Interval ◽  
Uranium Mineralization ◽  
Gamma Ray Spectrometry ◽  
Sultanate Of Oman ◽  
Near Surface ◽  
The World ◽  
Uranium Exploration ◽  
Proterozoic Basement

The Proterozoic basement of the Dhofar region of the Sultanate of Oman might be considered as a potential source of Uranium mineralization like other Proterozoic basins of the world, which collectively contribute 30%-40% to the global production.  Uranium exploration assumes great importance in this part of the world and therefore geochemical and geophysical exploration for Uranium was initiated.  Initial, random sampling of the study area with Gamma ray spectrometry as well as in situ XRF (Xray Florescence) analysis indicated the presence of   around 30-40 ppm of Uranium. Since Gamma ray spectrometry results in the calculation of the heat produced during radioactive decay of Potassium (K), Uranium (U) and Thorium (Th) within the rocks in the study area, measurements were acquired along eleven traverses of varying length from 100-250 m at a traverse interval of 20 m and sampling interval of 10 m. Individual plots of the concentrations  of radioelements such as U, K and Th have shown favorable anomalous radioactive sources. Besides this, Uranium to Thorium (eU/eTh) and Uranium to Potassium (eU/K) ratio plots have been presented and the alteration zones associated with Uranium mineralization through all traverses have been identified. Further, the generated composite ternary image based on the combination of K, Th and U from Gamma ray spectrometry determines different relative amounts of radioelements and paves the way for deciphering the level of radioactivity in the study area. However, there seems to be no presence of strong Uranium anomalies in the near surface of the limited study area. As the study area is heavily faulted, the depth to concealed  subsurface fault structures  is  estimated to be around  64 m based on Hartley spectral analysis of total magnetic anomaly (line-6). 

scholarly journals FERMI -LAT DISCOVERY OF GeV GAMMA-RAY EMISSION FROM THE YOUNG SUPERNOVA REMNANT CASSIOPEIA A

2010 ◽  
Vol 710 (1) ◽  
pp. L92-L97 ◽  
Author(s):  
A. A. Abdo ◽  
M. Ackermann ◽  
M. Ajello ◽  
A. Allafort ◽  
L. Baldini ◽  
...  
Keyword(s):  
Supernova Remnant ◽  
Gamma Ray ◽  
Cassiopeia A ◽  
Young Supernova Remnant ◽  
Gamma Ray Emission

URANIUM MEASUREMENT BY AIRBORNE GAMMA‐RAY SPECTROMETRY

Geophysics ◽  
1975 ◽  
Vol 40 (3) ◽  
pp. 503-519 ◽  
Author(s):  
R. L. Grasty
Keyword(s):  
Point Source ◽  
Gamma Ray ◽  
Radioactive Decay ◽  
High Energy ◽  
Gamma Ray Spectrometry ◽  
High Energy Radiation ◽  
Energy Radiation ◽  
Airborne Measurement ◽  
Decay Series ◽  
Different Depths

In the airborne measurement of uranium, window type gamma‐ray spectrometers are used and it is necessary to correct for scattered high energy radiation from thallium 208 in the thorium decay series. This radiation can be scattered in the crystal, in the ground, and in the air. A theory, analogous to the theory of radioactive decay, is developed; it can adequately explain the spectrum buildup in the uranium window for a point source of thorium oxide immersed to different depths in water and for a detector above the water. The theory is extended to predict the buildup as a function of altitude for detectors of different sizes and shows that errors in the airborne measurement of uranium can be, significant if no allowance is made for radiation scattered in the ground and in the air.

COMPTEL observations of 44Ti gamma-ray line emission from Cas A

1994 ◽  
Author(s):  
A. F. Iyudin ◽  
R. Diehl ◽  
G. G. Lichti ◽  
V. Schönfelder ◽  
H. Steinle ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Line Emission ◽  
Cas A
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