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Related papers: Gamma-ray fluxes in Oklo natural reactors

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A flux-calibrated high resolution spectrum of the airglow emission is a practical lambda-calibration reference for astronomical spectral observations. It is also useful for constraining the molecular parameters of the OH molecule and the…

It has been pointed out by Shlyakhter that data from the natural fission reactors which operated about two billion years ago at Oklo (Gabon) had the potential of providing an extremely tight bound on the variability of the fine-structure…

High Energy Physics - Phenomenology · Physics 2016-09-06 Thibault Damour , Freeman Dyson

Prompt fission $\gamma$-rays are responsible for approximately 5\% of the total energy released in fission, and therefore important to understand when modelling nuclear reactors. In this work we present prompt $\gamma$-ray emission…

Reaction cross sections of 169Tm(alpha,gamma)173Lu and 169Tm(alpha,n)172Lu have been measured in the energy range 12.6<=E_alpha<=17.5 MeV and 11.5<=E_alpha<=17.5 MeV, respectively, using the recently introduced method of combining…

$\gamma$-ray production cross sections have been measured in proton irradiations of N, Ne and Si and $\alpha$-particle irradiations of N and Ne. In the same experiment we extracted also line shapes for strong $\gamma$-ray lines of $^{16}$O…

We test common fluence diagnostics in the regime of very low burnup natural uranium reactor samples. The fluence diagnostics considered are the uranium isotopics ratios $^{235}$U/$^{238}$U and $^{236}$U/$^{235}$U, for which we find simple…

Instrumentation and Detectors · Physics 2017-11-08 Patrick Jaffke , Benjamin Byerly , Jamie Doyle , Anna Hayes , Gerard Jungman , Steven Myers , Angela Olson , Donivan Porterfield , Lav Tandon

One of the most important predictions of any gap model for pulsar magnetospheres is the predicted $\gamma$-ray spectra. In the outer gap model, the properties of the synchro-curvature radiation are sensitive to many parameters, whose…

High Energy Astrophysical Phenomena · Physics 2015-04-02 Daniele Viganò , Diego F. Torres , Kouichi Hirotani , Martín E. Pessah

The ratio between the rates of the reactions O-17(\alpha,n)Ne-20 and O-17(\alpha,\gamma)Ne-21 determines whether O-16 is an efficient neutron poison for the s process in massive stars, or if most of the neutrons captured by O-16(n,\gamma)…

We use the Monte Carlo particle physics code FLUKA (Fluktuierende Kaskade) to calculate $\gamma$-ray spectra expected from solar flare energetic ion distributions. The FLUKA code includes robust physics-based models for electromagnetic,…

The energetics and emission mechanism of GRBs are not well understood. Here we demonstrate that the instantaneous peak flux or equivalent isotropic peak luminosity, L_iso ergs s^-1, rather than the integrated fluence or equivalent isotropic…

Astrophysics · Physics 2007-10-22 R. Willingale , P. T. O'Brien , M. R. Goad , J. P. Osborne , K. L. Page , N. R. Tanvir

We investigate wheter there is any correlation between the X-ray afterglow luminosity and the prompt emission properties of a carefully selected sub-sample of bright Swift long Gamma-Ray Bursts (GRBs) nearly complete in redshift (~90%).…

Equilibrium molecular dynamics simulations are used to calculate the thermal conductivity of the one component plasma (OCP) via the Green-Kubo formalism over a broad range of Coulomb coupling strength, $0.1\le\Gamma\le180$. These…

Plasma Physics · Physics 2019-10-30 Brett Scheiner , Scott D. Baalrud

We analyze a pair of Suzaku shadowing observations in order to determine the X-ray spectrum of the Galaxy's gaseous halo. We simultaneously fit the spectra with models having halo, local, and extragalactic components. The intrinsic…

Astrophysics of Galaxies · Physics 2009-07-24 Shijun Lei , Robin L. Shelton , David B. Henley

The correlations between the rest frame peak of the EF_E spectrum of GRBs Epeak and their isotropic energy (E_iso) or luminosity (L_iso) could have several implications for the understanding of the GRB prompt emission. These correlations…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Giancarlo Ghirlanda

In the analysis of the Oklo (gabon) natural reactor to test for a possible time variation of the fine structure constant alpha, a Maxwell-Boltzmann low energy neutron spectrum was assumed. We present here an analysis where a more realistic…

Nuclear Theory · Physics 2009-11-10 S. K. Lamoreaux

We estimate the bulk Lorentz factor Gamma_0 of 31 GRBs using the measured peak time of their afterglow light curves. We consider two possible scenarios for the estimate of Gamma_0: the case of a homogeneous circumburst medium or a wind…

High Energy Astrophysical Phenomena · Physics 2015-05-28 G. Ghirlanda , L. Nava , G. Ghisellini , A. Celotti , D. Burlon , S. Covino , A. Melandri

In this paper we further investigate the relationship, reported by Oates et al., 2012, between the optical/UV afterglow luminosity (measured at restframe 200s) and average afterglow decay rate (measured from restframe 200s onwards) of long…

High Energy Astrophysical Phenomena · Physics 2015-09-30 S. R. Oates , J. L. Racusin , M. De Pasquale , M. J. Page , A. J. Castro-Tirado , J. Gorosabel , P. J. Smith , A. A. Breeveld , N. P. M Kuin

Gamma-ray burst (GRB) prompt emission is commonly attributed to non-thermal radiation processes operating in the optically thin regions of a relativistic outflow. Among these, optically thin inverse-Compton (IC) scattering remains an…

High Energy Astrophysical Phenomena · Physics 2026-03-31 Pragyan Pratim Bordoloi , Shubh Mittal , Shabnam Iyyani

The Fermi LAT discovery that classical novae produce >100 MeV gamma-rays establishes that shocks and relativistic particle acceleration are key features of these events. These shocks are likely to be radiative due to the high densities of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Brian D. Metzger , Thomas Finzell , Indrek Vurm , Romain Hascoet , Andrei M. Beloborodov , Laura Chomiuk

Physical processes working in the stellar interiors as well as the evolution of stars depend on some fundamental stellar properties, such as mass, radius, luminosity, and chemical abundances. A classical way to test stellar interior models…