14,542 research outputs found
Spectral analysis of Markarian 421 and Markarian 501 with HAWC
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 5 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
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
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.
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.
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.
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
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 at the same resolution, which in this work is 3.6. 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- 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 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 .Comment: Revised to match the version on press in MNRAS. Different
interpretation of differences vs WMAP 7. 10 pages, 6 tables, 8 figure
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