14,542 research outputs found

    Spectral analysis of Markarian 421 and Markarian 501 with HAWC

    Full text link
    The Hight Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory monitors the gamma-ray sky in the energy range from 100 GeV to 100 TeV and has detected two very high energy (VHE) blazars: Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501) in 1.5 years of observations. In this work, we present the spectral analysis above 1 TeV of both sources using a maximum likelihood method and an artificial neural network as an energy estimator. The main objectives are to constrain the spectral curvature of Mrk 421 and Mrk 501 at \sim5 TeV using the EBL models from Gilmore et al. (2012) and Franceschini et al. (2008).Comment: Presented at the 35th International Cosmic Ray Conference (ICRC2017), Bexco, Busan, Korea. See arXiv:1708.02572 for all HAWC contribution

    Scaling of variables and the relation between noncommutative parameters in Noncommutative Quantum Mechanics

    Full text link
    We consider Noncommutative Quantum Mechanics with phase space noncommutativity. In particular, we show that a scaling of variables leaves the noncommutative algebra invariant, so that only the self-consistent effective parameters of the model are physically relevant. We also discuss the recently proposed relation of direct proportionality between the noncommutative parameters, showing that it has a limited applicability.Comment: Revtex4, 4 pages; version to match the published on

    Swift-XRT observation of 34 new INTEGRAL/IBIS AGNs: discovery of Compton thick and other peculiar sources

    Full text link
    For a significant number of the sources detected at high energies (>10 keV) by the INTEGRAL/IBIS and Swift/BAT instruments there is either a lack information about them in the 2-10 keV range or they are totally unidentified. Herein, we report on a sample of 34 IBIS AGN or AGN candidate objects for which there is X-ray data in the Swift/XRT archive. Thanks to these X-ray follow up observations, the identification of the gamma ray emitters has been possible and the spectral shape in terms of photon index and absorption has been evaluated for the first time for the majority of our sample sources. The sample, enlarged to include 4 more AGN already discussed in the literature, has been used to provide photon index and column density distribution. We obtain a mean value of 1.88 with a dispersion of 0.12, i.e. typical of an AGN sample. Sixteen objects (47%) have column densities in excess of 10^{22} cm^{-2} and, as expected, a large fraction of the absorbed sources are within the Sey 2 sample. We have provided a new diagnostic tool (NH versus F(2-10)keV/F(20-100)keV softness ratio) to isolate peculiar objects; we find at least one absorbed Sey 1 galaxy, 3 Compton thick AGN candidates; and one secure example of a "true" type 2 AGN. Within the sample of 10 still unidentified objects, 3 are almost certainly AGN of type 2; 3 to 4 have spectral slopes typical of AGN; and two are located high on the galactic plane and are strong enough radio emitters so that can be considered good AGN candidates.Comment: 15 pages, 5 figures, ApJ accepte

    Controle de adultos e ninfas da mosca-branca Bemisia tabaci biótipo B com Chlorantraniliprole + Thiamethoxan.

    Get PDF
    Neste trabalho foi determinada a eficiência da mistura dos inseticidas Chlorantraniliprole + Thiametoxan em pulverização foliar no controle de ninfas e adultos da mosca-branca Bemisia tabaci Biótipo B no feijoeiro.bitstream/CNPAF-2009-09/28135/1/comt_165.pd

    Redução alimentar de Neomegalotomus simplex em sementes de feijão tratadas com óleo de nim.

    Get PDF
    O objetivo deste trabalho foi avaliar o efeito de diferentes concentrações do óleo de nim sobre a atividade alimentar de adultos de Neomegalotomus simplex

    Efeito do Voliam Flexi sobre a mosca-branca Bemisia tabaci biótipo B no feijoeiro.

    Get PDF
    O objetivo do trabalho foi avaliar a eficiência do inseticida Voliam Flexi em pulverização foliar no controle de adultos da mosca-branca Bemisia tabaci Biótipo B no feijoeiro

    Cosmological Parameters from a re-analysis of the WMAP-7 low resolution maps

    Full text link
    Cosmological parameters from WMAP 7 year data are re-analyzed by substituting a pixel-based likelihood estimator to the one delivered publicly by the WMAP team. Our pixel based estimator handles exactly intensity and polarization in a joint manner, allowing to use low-resolution maps and noise covariance matrices in T,Q,UT,Q,U at the same resolution, which in this work is 3.6^\circ. We describe the features and the performances of the code implementing our pixel-based likelihood estimator. We perform a battery of tests on the application of our pixel based likelihood routine to WMAP publicly available low resolution foreground cleaned products, in combination with the WMAP high-\ell likelihood, reporting the differences on cosmological parameters evaluated by the full WMAP likelihood public package. The differences are not only due to the treatment of polarization, but also to the marginalization over monopole and dipole uncertainties implemented in the WMAP 7 year pixel likelihood code for temperature. The credible central value for the cosmological parameters change below the 1 σ\sigma level with respect to the evaluation by the full WMAP 7 year likelihood code, with the largest difference in a shift to smaller values of the scalar spectral index nSn_S.Comment: Revised to match the version on press in MNRAS. Different interpretation of differences vs WMAP 7. 10 pages, 6 tables, 8 figure
    corecore