A new Determination of the Extragalactic Background of Diffuse Gamma Rays taking into account Dark Matter Annihilation

The extragalactic background (EGB) of diffuse gamma rays can be determined by subtracting the Galactic contribution from the data. This requires a Galactic model (GM) and we include for the first time the contribution of dark matter annihilation (DMA), which was previously proposed as an explanation for the EGRET excess of diffuse Galactic gamma rays above 1 GeV. In this paper it is shown that the newly determined EGB shows a characteristic high energy bump on top of a steeply falling soft contribution. The bump is shown to be compatible with a contribution from an extragalactic DMA signal from weakly interacting massive particles (WIMPs) with a mass between 50 and 100 GeV in agreement with the EGRET excess of the Galactic diffuse gamma rays and in disagreement with earlier analysis. The remaining soft contribution of the EGB is shown to resemble the spectra of the observed point sources in our Galaxy.Comment: 7 pages, 4 figures. Accepted by A&A, made Fig. 4 and table 1 consisten

Mass spectrometry in structural and stereochemical problems. Part 178 - The electron-impact promoted fragmentation of 1,2-cyclohexene oxide

Mass spectra of 1,2-cyclohexane oxide and three deuterium labeled analog

Parameterization of the Angular Distribution of Gamma Rays Produced by p-p Interaction in Astronomical Environment

We present the angular distribution of gamma rays produced by proton-proton interactions in parameterized formulae to facilitate calculations in astrophysical environments. The parameterization is derived from Monte Carlo simulations of the up-to-date proton-proton interaction model by Kamae et al. (2005) and its extension by Kamae et al. (2006). This model includes the logarithmically rising inelastic cross section, the diffraction dissociation process and Feynman scaling violation. The extension adds two baryon resonance contributions: one representing the Delta(1232) and the other representing multiple resonances around 1600 MeV/c^2. We demonstrate the use of the formulae by calculating the predicted gamma-ray spectrum for two different cases: the first is a pencil beam of protons following a power law and the second is a fanned proton jet with a Gaussian intensity profile impinging on the surrounding material. In both cases we find that the predicted gamma-ray spectrum to be dependent on the viewing angle.Comment: 8 pages, 7 figures, figure 7 updated, accepted for publication in ApJ, text updated to match changes by the editor, two refs updated from preprints to full journal

INDICATIONS OF TISSUE SPECIFICITY IN A TRANSPLANTABLE SARCOMA

1. A sarcoma of the mouse which has proved to be transplantable to a great variety of strains of mice does not furnish an exception to the theory that transplantability is controlled by genetic factors, since this tumor possesses some characteristics that are more than probably genetic. 2. The phenomenon of the assumption of tissue specificity on the part of the host may possibly be of genetic origin. 3. The evidence suggests that the gonads have some influence on the assumption of tissue specificity on the part of the host. 4. The growth rate of the transplanted tumor may possibly be correlated with the genetic constitution of the host

CHANGES IN THE REACTION POTENTIAL OF A TRANSPLANTABLE TUMOR

A transplantable tumor, known as dBrD, gave very uniform results in a series of mice of known pedigree for a period of about a year. See PDF for Structure We may say that the reaction potential existing between the tumor and individuals inoculated was the same during this first part of the experiment. This tumor will grow in a mouse progressively provided there be present simultaneously at least from six to eight independently segregating genetic factors (genes) in the fundamental make-up of the host derived from the zygote that gave rise to the individual. In the course of routine transplantation of this tumor, there was a sudden change in this hitherto constant reaction potential resulting in at least three types of transplantable tumors—new types as far as their physiological activity and reaction potential are concerned. From a single original transplantable mass, I have therefore obtained four masses that remain true to type at least for some months of continued experimentation. These four types are (1) the original tumor, dBrD, still giving a six to eight Mendelian factor ratio, (2) dBrDm giving a two factor ratio, (3) dBrDBl showing another two factor ratio, and (4) dBrDBs giving a one factor ratio. The number of factors involved in the transplantability for the several tumors investigated are given in Table III