Spectra of Unsteady Wind Models of Gamma-Ray Bursts

We calculate the spectra expected from unsteady relativistic wind models of gamma-ray bursts, suitable for events of arbitrary duration. The spectral energy distribution of the burst is calculated over photon energies spanning from eV to TeV, for a range of event durations and variability timescales. The relative strength of the emission at different wavelengths can provide valuable information on the particle acceleration, radiation mechanisms and the possible types of models.Comment: 10 pages, 2 postscript figures included, uses aaspp4.sty. Accepted for publication in the Astrophysical Journal Letters. Also available at http://www.astro.psu.edu/users/hara/Preprints/xxx_sub.p

Department of Defense's 2015 retirement plan cost analysis

MBA Professional ReportThe new military retirement system is advertised to significantly reduce the Department of Defense's (DOD) monetary outlays over the short and long term. These savings are generated through a variety of assumptions outside of the department's control. The variables that have the greatest impact over cost savings are controlled by service members' (SM) actions, choices, and federal interest rates. Critical analysis of these variables could potentially affect future cost savings and is key in budget preparation and future spending plans. This MBA report presents a sensitivity analysis on three separate variables that have a significant impact on retirement costs. Realistic manipulation of these independent variables will show short-term versus long-term cost savings. Additionally, a high-cost and low-cost scenario is explored. With cost scenarios differing up to $321 billion, DOD needs to be aware of the potential effects of future outlays. It is recommended that DOD conduct additional economic research and acquire further data on the preferences of current SMs in order to provide a more narrow range of cost savings.http://archive.org/details/departmentofdefe1094549480Lieutenant Commander, United States NavyLieutenant, United States NavyLieutenant, United States NavyApproved for public release; distribution is unlimited

Emission Spectra from Internal Shocks in Gamma-Ray-Burst Sources

Unsteady activity of gamma-ray burst sources leads to internal shocks in their emergent relativistic wind. We study the emission spectra from such shocks, assuming that they produce a power-law distribution of relativistic electrons and posses strong magnetic fields. The synchrotron radiation emitted by the accelerated electrons is Compton up-scattered multiple times by the same electrons. A substantial component of the scattered photons acquires high energies and produces e+e- pairs. The pairs transfer back their kinetic energy to the radiation through Compton scattering. The generic spectral signature from pair creation and multiple Compton scattering is highly sensitive to the radius at which the shock dissipation takes place and to the Lorentz factor of the wind. The entire emission spectrum extends over a wide range of photon energies, from the optical regime up to TeV energies. For reasonable values of the wind parameters, the calculated spectrum is found to be in good agreement with the burst spectra observed by BATSE.Comment: 12 pages, latex, 2 figures, submitted to ApJ

La mujer en la iglesia : cuestión de solidaridad

Después de dos años de haber "participado en el diálogo con un grupo de mujeres, unas de la clase trabajadora, otras de la clase media", Brian Lennon, Gerry O'Hanlon, Bill Toner y Frank Sammon, jesuitas irlandeses, presentan algunos puntos de vista aportados por estas mujeres y dan una respuesta inicial en el documento La mujer en la iglesia. Cuestión de solidaridad. Este texto va acompañado del decreto de la Congregación General 34 de la Compañía de Jesús sobre la Compañía y la situación de la mujer en la iglesia y en la sociedad. Ambos testimonios nos invitan a la reflexión en lo que se refiere a nuestras actitudes y pautas de comportamiento hacia la mujer, creatura, como el hombre, a imagen y semejanza de Dios. Esta publicación busca avanzar en la comprensión de asunto tan vital y demandante.ITESO, A.C

COMPTEL measurements of MeV gamma-ray burst spectra

We present results from the on-going spectral analysis of gamma-ray bursts measured by the COMPTEL instrument in its main Compton “Telescope” observing mode (0.75–30 MeV). Thus far, 18 bursts have been analyzed from three years (April 1991–April 1994) of observations. The time-averaged spectra of these events above 1 MeV are all consistent with a simple power law model with spectral index in the range 1.5–3.5. Exponential, thermal bremsstrahlung and thermal synchrotron models are statistically inconsistent with the burst sample, although they can adequately describe some of the individual burst spectra. We find good agreement between burst spectra measured simultaneously by BATSE, COMPTEL and EGRET, which typically show a spectral transition or “break” in the BATSE energy range around a few hundred keV followed by simple power law emission extending to hundreds of MeV. However, the temporal relation between MeV and GeV (e.g., as measured by EGRET) burst emission is still unclear. Measurement of rapid variability at MeV energies in the stronger bursts provides evidence that either the sources are nearby (within the Galaxy) or the gamma-ray emission is relativistically beamed

COMPTEL observations of gamma‐ray flares in October 1991

The COMPTEL experiment on GRO images 0.75–30 MeV celestial gamma‐radiation that falls within its 1 steradian field of view. During observation 12 (primary target Cen A) in October 1991 the sun had been in the fov and several solar flares associated with the active region 6891 had been observed. Time profile and energy spectra had been produced, using COMPTEL’s primary mode of operation (the telescope mode). Additionally the number of counts received in the D2‐single burst detector (the secondary mode of operation) are given. We summarize the preliminary results on all of these flares

COMPTEL gamma ray and neutron measurements of solar flares

COMPTEL on the Compton Gamma Ray Observatory has measured the flux of x‐rays and neutrons from several solar flares. These data have also been used to image the Sun in both forms of radiation. Unusually intense flares occurred during June 1991 yielding data sets that offer some new insight into of how energetic protons and electrons are accelerated and behave in the solar environment. We summarize here some of the essential features in the solar flare data as obtained by COMPTEL during June 1991

The angular distribution of COMPTEL Gamma-Ray bursts

The superior burst location capability of the COMPTEL instrument aboard the Compton Gamma-Ray Observatory allows us to study the small-scale angular distribution of burst sources with good sensitivity even though the number of burst detections is small. We accumulate four years (April 1991–April 1995) of observations to form a catalog of 27 burst locations whose mean 1σ uncertainty is ∼1°. We find that the COMPTEL bursts are consistent with an isotropic distribution of sources, yet the spatial coincidence of two of the bursts within COMPTEL’s angular resolution indicates the possibility of repetition. This possibility is studied using the two-point angular correlation function and the nearest neighbor statistic. Model dependent upper limits on the fraction of repeating sources are derived