191 research outputs found

    Hard X-Ray Spectrum from West Lobe of Radio Galaxy Fornax A Observed with Suzaku

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    An observation of the West lobe of radio galaxy Fornax A (NGC 1316) with Suzaku is reported. Since Feigelson et al. (1995) and Kaneda et al. (1995) discovered the cosmic microwave background boosted inverse-Comptonized (IC) X-rays from the radio lobe, the magnetic field and electron energy density in the lobes have been estimated under the assumption that a single component of the relativistic electrons generates both the IC X-rays and the synchrotron radio emission. However, electrons generating the observed IC X-rays in the 1 -- 10 keV band do not possess sufficient energy to radiate the observed synchrotron radio emission under the estimated magnetic field of a few micro-G. On the basis of observations made with Suzaku, we show in the present paper that a 0.7 -- 20 keV spectrum is well described by a single power-law model with an energy index of 0.68 and a flux density of 0.12+/-0.01 micro-Jy at 1 keV from the West lobe. The derived multiwavelength spectrum strongly suggests that a single electron energy distribution over a Lorentz factor gamma = 300 - 90000 is responsible for generating both the X-ray and radio emissions. The derived physical quantities are not only consistent with those reported for the West lobe, but are also in very good agreement with those reported for the East lobe.Comment: 8 pages, 6 figures; accepted for publication in PASJ (Publications of the Astronomical Society of Japan) Suzaku 3rd special issue: TYPOS in flux density unit were correcte

    Test of the Conserved Vector Current Hypothesis by beta-ray Angular Distribution Measurement in the Mass-8 System

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    The beta-ray angular correlations for the spin alignments of 8Li and 8B have been observed in order to test the conserved vector current (CVC) hypothesis. The alignment correlation terms were combined with the known beta-alpha-angular correlation terms to determine all the matrix elements contributing to the correlation terms. The weak magnetism term, 7.5\pm0.2, deduced from the beta-ray correlation terms was consistent with the CVC prediction 7.3\pm0.2, deduced from the analog-gamma-decay measurement based on the CVC hypothesis. However, there was no consistent CVC prediction for the second-forbidden term associated with the weak vector current. The experimental value for the second-forbidden term was 1.0 \pm 0.3, while the CVC prediction was 0.1 \pm 0.4 or 2.1 \pm 0.5.Comment: 31 pages, 12 figures, Accepted for publication in Phys. Rev.

    Quantum Monte Carlo calculations of A=9,10A=9,10 nuclei

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    We report on quantum Monte Carlo calculations of the ground and low-lying excited states of A=9,10A=9,10 nuclei using realistic Hamiltonians containing the Argonne v18v_{18} two-nucleon potential alone or with one of several three-nucleon potentials, including Urbana IX and three of the new Illinois models. The calculations begin with correlated many-body wave functions that have an α\alpha-like core and multiple p-shell nucleons, LSLS-coupled to the appropriate (Jπ;T)(J^{\pi};T) quantum numbers for the state of interest. After optimization, these variational trial functions are used as input to a Green's function Monte Carlo calculation of the energy, using a constrained path algorithm. We find that the Hamiltonians that include Illinois three-nucleon potentials reproduce ten states in 9^9Li, 9^9Be, 10^{10}Be, and 10^{10}B with an rms deviation as little as 900 keV. In particular, we obtain the correct 3+^+ ground state for 10^{10}B, whereas the Argonne v18v_{18} alone or with Urbana IX predicts a 1+^+ ground state. In addition, we calculate isovector and isotensor energy differences, electromagnetic moments, and one- and two-body density distributions.Comment: 28 pages, 12 tables, 7 figure

    Suzaku observation of the giant radio galaxy 3C 326

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    A Suzaku observation of a giant radio galaxy, 3C 326, which has a physical size of about 2 Mpc, was conducted on 2008 January 19 -- 21. In addition to several X-ray sources, diffuse emission was significantly detected associated with its west lobe, but the east lobe was contaminated by an unidentified X-ray source WARP J1552.4+2007. After careful evaluation of the X-ray and Non X-ray background, the 0.4 -- 7 keV X-ray spectrum of the west lobe is described by a power-law model. The photon index and 1 keV flux density was derived as 1.820.24+0.26±0.041.82_{-0.24}^{+0.26}\pm0.04 and 19.43.2+3.3±3.019.4_{-3.2}^{+3.3}\pm 3.0 nJy, respectively, where the first and second errors represent the statistical and systematic ones. The diffuse X-rays were attributed to be inverse Compton radiation by the synchrotron radio electrons scattering off the cosmic microwave background photons. This radio galaxy is the largest among those with lobes detected through inverse Compton X-ray emission. A comparison of the radio to X-ray fluxes yields the energy densities of electron and magnetic field as ue=(2.3±0.3±0.3)×1013u_e = (2.3 \pm 0.3 \pm 0.3) \times 10^{-13} ergs/cm3 and um=(1.20.1+0.2±0.2)×1014u_m = (1.2_{-0.1}^{+0.2}\pm 0.2) \times 10^{-14} ergs/cm3, respectively. The galaxy is suggested to host a low luminosity nucleus with an absorption-corrected 2 -- 10 keV luminosity of <2×1042<2 \times 10^{42} ergs/s, together with a relatively weak radio core. The energetics in the west lobe of 3C 326 were compared with those of moderate radio galaxies with a size of 100\sim 100 kpc. The west lobe of 3C 326 is confirmed to agree with the correlations for the moderate radio galaxies, ueD2.2±0.4u_e \propto D^{-2.2\pm0.4} and umD2.4±0.4u_m \propto D^{-2.4\pm0.4}, where DD is their total physical size. This implies that the lobes of 3C 326 are still being energized by the jet, despite the current weakness of the nucleus.Comment: 11 pages, 10 figures, 6 tables, Accepted for ApJ (v706 issue

    Measurement of the spin and magnetic moment of 23Al

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    For the first time, we obtained the g factor for the ground state of 23Al by use of a -NMR measurement. 23Al has a small proton separation energy and is a potential proton-halo candidate. The obtained g factor, |g|=1.557±0.088, clearly shows the spin and parity, J=5/2+, for 23Al, which is the same as that of its mirror partner, 23Ne. The possible nuclear structure of 23Al is also discussed

    Neurophysiological modeling of bladder afferent activity in the rat overactive bladder model

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    The overactive bladder (OAB) is a syndrome-based urinary dysfunction characterized by “urgency, with or without urge incontinence, usually with frequency and nocturia”. Earlier we developed a mathematical model of bladder nerve activity during voiding in anesthetized rats and found that the nerve activity in the relaxation phase of voiding contractions was all afferent. In the present study, we applied this mathematical model to an acetic acid (AA) rat model of bladder overactivity to study the sensitivity of afferent fibers in intact nerves to bladder pressure and volume changes. The afferent activity in the filling phase and the slope, i.e., the sensitivity of the afferent fibers to pressure changes in the post-void relaxation phase, were found to be significantly higher in AA than in saline measurements, while the offset (nerve activity at pressure ~0) and maximum pressure were comparable. We have thus shown, for the first time, that the sensitivity of afferent fibers in the OAB can be studied without cutting nerves or preparation of single fibers. We conclude that bladder overactivity induced by AA in rats is neurogenic in origin and is caused by increased sensitivity of afferent sensors in the bladder wall
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