18,819 research outputs found

    Recent extensions to GALPROP

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    Some recent extensions to the GALPROP cosmic-ray propagation package are described. The enhancements include: an accurate solution option, improved convection formulation, alternative spatial boundary conditions, polarized synchrotron emission, new magnetic field models, updated gamma-ray production cross-sections, free-free radio emission and absorption, primary positrons, additional injection spectral breaks, deuterium production by pp fusion, hadronic energy losses, improved HEALPix skymap format, compatibility with latest HEALPix release, and various bug fixes. The Explanatory Supplement has been extensively updated, including details of these enhancements. A compatible plot package GALPLOT for GALPROP output is also provided, as well as other related software.Comment: Contribution to the 34th International Cosmic Ray Conference, July 30 to August 6, The Hague, Netherland

    Evaluation of ERTS data for certain oceanographic uses

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    The author has identified the following significant results. Upwelling along the eastern shore of Lake Michigan was occurring during the 3 and 21 August 1973 visits by ERTS-1. The NOAA-2 VHRR thermal-IR data are being digitized for comparison. Early indications are that these upwellings induced a calcium carbonate precipitate to form in the surface waters. It is most pronounced in the MSS-4 channel. On the lake bottom this jell-like sediment is known as marl and adds to the eutrophication of the lake. This phenomenon may help to explain the varve-like nature of bottom cores that have been observed in the Great Lakes

    Gamma-ray emission from the solar halo and disk: a study with EGRET data

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    Context: The Sun has recently been predicted to be an extended source of gamma-ray emission, produced by inverse-Compton (IC) scattering of cosmic-ray (CR) electrons on the solar radiation field. The emission was predicted to be extended and a confusing foreground for the diffuse extragalactic background even at large angular distances from the Sun. The solar disk is also expected to be a steady gamma-ray source. While these emissions are expected to be readily detectable in the future by GLAST, the situation for available EGRET data is more challenging. Aims: The theory of gamma-ray emission from IC scattering on the solar radiation field by Galactic CR electrons is given in detail. This is used as the basis for detection and model verification using EGRET data. Methods: We present a detailed study of the solar emission using the EGRET database, accounting for the effect of the emission from 3C 279, the moon, and other sources, which interfere with the solar emission. The analysis was performed for 2 energy ranges, above 300 MeV and for 100-300 MeV, as well as for the combination to improve the detection statistics. The technique was tested on the moon signal, with our results consistent with previous work. Results: Analyzing the EGRET database, we find evidence of emission from the solar disk and its halo. The observations are compared with our model for the extended emission. The spectrum of the solar disk emission and the spectrum of the extended emission have been obtained. The spectrum of the moon is also given. Conclusions: The observed intensity distribution and the flux are consistent with the predicted model of IC gamma-rays from the halo around the Sun.Comment: Corrected typos, added acknowledgements. A&A in pres

    Stirring apparatus for plural test tubes Patent

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    Design of mechanical device for stirring several test tubes simultaneousl
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