4,374 research outputs found

    Dislocation model for aseismic fault slip in the transverse ranges of Southern California

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    Geodetic data at a plate boundary can reveal the pattern of subsurface displacements that accompany plate motion. These displacements are modelled as the sum of rigid block motion and the elastic effects of frictional interaction between blocks. The frictional interactions are represented by uniform dislocation on each of several rectangular fault patches. The block velocities and fault parameters are then estimated from geodetic data. Bayesian inversion procedure employs prior estimates based on geological and seismological data. The method is applied to the Transverse Ranges, using prior geological and seismological data and geodetic data from the USGS trilateration networks. Geodetic data imply a displacement rate of about 20 mm/yr across the San Andreas Fault, while the geologic estimates exceed 30 mm/yr. The prior model and the final estimates both imply about 10 mm/yr crustal shortening normal to the trend of the San Andreas Fault. Aseismic fault motion is a major contributor to plate motion. The geodetic data can help to identify faults that are suffering rapid stress accumulation; in the Transverse Ranges those faults are the San Andreas and the Santa Susana

    Radiation Transfer in the Cavity and Shell of Planetary Nebulae

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    We develop an approximate analytical solution for the transfer of line-averaged radiation in the hydrogen recombination lines for the ionized cavity and molecular shell of a spherically symmetric planetary nebula. The scattering problem is treated as a perturbation, using a mean intensity derived from a scattering-free solution. The analytical function was fitted to Halpha and Hbeta data from the planetary nebula NGC6537. The position of the maximum in the intensity profile produced consistent values for the radius of the cavity as a fraction of the radius of the dusty nebula: 0.21 for Halpha and 0.20 for Hbeta. Recovered optical depths were broadly consistent with observed optical extinction in the nebula, but the range of fit parameters in this case is evidence for a clumpy distribution of dust.Comment: MNRAS accepted; 10 Fig

    Affleck-Dine Baryogenesis and heavy elements production from Inhomogeneous Big Bang Nucleosynthesis

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    We study the impact of possible high density baryonic bubbles on the early formed QSO, IGM, and metal poor stars. Such bubbles could be created, under certain conditions, in Affleck-Dine model of baryogenesis and may occupy a relatively small fraction of space, while the dominant part of the cosmological volume has the normal observed baryon-to-photon ratio η=6⋅10−10\eta = 6\cdot 10^{-10}. The value of η\eta in the bubbles, could be much larger than the usually accepted one (it might be even close to unity) without contradicting the existing data on light element abundances and the observed angular spectrum of CMBR. We find upper bounds on η\eta by comparing heavy elements' abundances produced in BBN and those of metal poor stars. We conclude that η\eta should be smaller than 10−510^{-5} in some metal poor star regions.Comment: 11 pages, 4 figures, PTPTeX ; added references, changed introduction, acknowledgments and figure

    Melting Pattern of Diquark Condensates in Quark Matter

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    Thermal color superconducting phase transitions in high density three-flavor quark matter are investigated in the Ginzburg-Landau approach. Effects of nonzero strange quark mass, electric and color charge neutrality, and direct instantons are considered. Weak coupling calculations show that an interplay between the mass and electric neutrality effects near the critical temperature gives rise to three successive second-order phase transitions as the temperature increases: a modified color-flavor locked (mCFL) phase (ud, ds, and us pairings) -> a ``dSC'' phase (ud and ds pairings) -> an isoscalar pairing phase (ud pairing) -> a normal phase (no pairing). The dSC phase is novel in the sense that while all eight gluons are massive as in the mCFL phase, three out of nine quark quasiparticles are gapless.Comment: minor changes in the text, fig.2 modifie

    Energy Spectra and Energy Correlations in the Decay H→ZZ→Ό+Ό−Ό+Ό−H\to ZZ\to \mu^+\mu^-\mu^+\mu^-

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    It is shown that in the sequential decay H→ZZ→(f1f1ˉ)+(f2f2ˉ)H\to ZZ\to (f_1\bar{f_1})+ (f_2\bar{f_2}), the energy distribution of the final state particles provides a simple and powerful test of the HZZHZZ vertex. For a standard Higgs boson, the energy spectrum of any final fermion, in the rest frame of HH, is predicted to be dΓ/dx∌1+ÎČ4−2(x−1)2d\Gamma /dx\sim 1+\beta^4-2(x-1)^2, with ÎČ=1−4mZ2/mH2\beta = \sqrt{1-4m^2_Z/m^2_H} and 1−ÎČ≀x=4E/mH≀1+ÎČ1-\beta \le x=4E/m_H\le 1+\beta . By contrast, the spectrum for a pseudoscalar Higgs is dΓ/dx∌ÎČ2+(x−1)2d\Gamma /dx \sim \beta^2+(x-1)^2. There are characteristic energy correlations between f1f_1 and f2f_2 and between f1f_1 and f2ˉ\bar{f_2}. These considerations are applied to the ``gold--plated'' reaction H→ZZ→Ό+Ό−Ό+Ό−H\to ZZ\to \mu^+\mu^-\mu^+\mu^-, including possible effects of CP--violation in the HZZHZZ coupling. Our formalism also yields the energy spectra and correlations of leptons in the decay H→W+W−→l+Îœll−ΜlˉH\to W^+W^-\to l^+\nu_ll^- \bar{\nu_l}.Comment: 14 pages + 4 figure

    Adaptive Dispersion Compensation for Remote Fiber Delivery of NIR Femtosecond Pulses

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    We report on remote delivery of 25 pJ broadband near-infrared femtosecond light pulses from a Ti:sapphire laser through 150 meters of single-mode optical fiber. Pulse distortion due to dispersion is overcome with pre-compensation using adaptive pulse shaping techniques, while nonlinearities are mitigated using an SF10 rod for the final stage of pulse compression. Near transform limited pulse duration of 130 fs is measured after the final compression.Comment: 3 pages, 4 figure

    A decade of ejecta dust formation in the Type IIn SN 2005ip

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    In order to understand the contribution of core-collapse supernovae to the dust budget of the early universe, it is important to understand not only the mass of dust that can form in core-collapse supernovae but also the location and rate of dust formation. SN 2005ip is of particular interest since dust has been inferred to have formed in both the ejecta and the post-shock region behind the radiative reverse shock. We have collated eight optical archival spectra that span the lifetime of SN 2005ip and we additionally present a new X-shooter optical-near-IR spectrum of SN 2005ip at 4075d post-discovery. Using the Monte Carlo line transfer code DAMOCLES, we have modelled the blueshifted broad and intermediate width Hα\alpha, HÎČ\beta and He I lines from 48d to 4075d post-discovery using an ejecta dust model. We find that dust in the ejecta can account for the asymmetries observed in the broad and intermediate width Hα\alpha, HÎČ\beta and He I line profiles at all epochs and that it is not necessary to invoke post-shock dust formation to explain the blueshifting observed in the intermediate width post-shock lines. Using a Bayesian approach, we have determined the evolution of the ejecta dust mass in SN 2005ip over 10 years presuming an ejecta dust model, with an increasing dust mass from ~10−8^{-8} M⊙_{\odot} at 48d to a current dust mass of ∌\sim0.1 M⊙_{\odot}.Comment: Accepted by MNRAS, 17 pages, 11 figures. Author accepted manuscript. Accepted on 04/03/19. Deposited on 07/03/1

    AKARI Near- to Mid-Infrared Imaging and Spectroscopic Observations of the Small Magellanic Cloud. I. Bright Point Source List

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    We carried out a near- to mid-infrared imaging and spectroscopic observations of the patchy areas in the Small Magellanic Cloud using the Infrared Camera on board AKARI. Two 100 arcmin2 areas were imaged in 3.2, 4.1, 7, 11, 15, and 24 um and also spectroscopically observed in the wavelength range continuously from 2.5 to 13.4 um. The spectral resolving power (lambda/Delta lambda) is about 20, 50, and 50 at 3.5, 6.6 and 10.6 um, respectively. Other than the two 100 arcmin2 areas, some patchy areas were imaged and/or spectroscopically observed as well. In this paper, we overview the observations and present a list of near- to mid-infrared photometric results, which lists ~ 12,000 near-infrared and ~ 1,800 mid-infrared bright point sources detected in the observed areas. The 10 sigma limits are 16.50, 16.12, 13.28, 11.26, 9.62, and 8.76 in Vega magnitudes at 3.2, 4.1, 7, 11, 15, and 24 um bands, respectively.Comment: 16 pages, 7 figures, accepted for publication in PASJ. Full resolution version is available at http://www-irc.mtk.nao.ac.jp/%7Eyita/smc20100112.pd

    Effect of different additives on the physical and chemical CO 2 absorption in polyetherimide hollow fiber membrane contactor system

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    Porous asymmetric polyetherimide (PEI) hollow fiber membranes were fabricated via a phase-inversion method using ethanol, glycerol and acetone as the additives in the spinning dope. Also, hollow fiber PEI membrane without additives was fabricated. An aqueous solution of 1-methyl-2-pyrrolidone (80 wt.%) was used as bore fluid to prevent forming of an inner dense skin layer. The precipitation rate of the polymer dopes with the different additives was studied using cloud point measurement. The effect of the additives on the resulting membrane structure, surface porosity, pore size, critical water entry pressure, collapsing pressure and physical and chemical CO2 absorption performance by distilled water and NaOH (1 M) solution in a gas–liquid membrane contactor system were investigated and compared. Cloud point diagrams indicated that the precipitation rate of the polymer dopes increased following the trend of ethanol > acetone > glycerol. Results of gas permeation tests showed that ethanol and glycerol as additives provided the membranes with the largest and smallest pore size, respectively. Moreover, all the additives resulted in an increase in the effective surface porosity. The cross-section of the membranes was examined via a scanning electron microscopy. Ethanol in the spinning dope provided the membrane structure with a sublayer with finger-like macrovoids, originating from the inner and outer surfaces of the hollow fiber and extending to the middle section of the hollow fiber wall, which resulted in a larger pore size and higher CO2 absorption rate than the other PEI hollow fiber membranes
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