92,051 research outputs found

    The mass estimate in narrow-line Seyfert 1 galaxies

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    It is possible that narrow-line Seyfert 1 galaxies (NLS1s) are in the early stage of active galactic nuclei (AGNs) evolution. It is important to estimate the mass of supermassive black hole (SBH) in NLS1s. Here we considered the different kinds of methods to estimate the SBH masses in NLS1s. The virial mass from the Hβ\beta linewidth assuming random orbits of broad line regions (BLRs) is consistent with that from the statured soft X-ray luminosity, which showed that most of NLS1s are in the super-Eddington accretion state. The mass from the [O III] linewidth is systematically larger than that from above two methods. It is necessary to measure he bulge stellar dispersion and/or bulge luminosity in NLS1s.Comment: 2 Pages, 1 figure, in Prof. IAU Symposium No. 222, "The interplay among Black Holes, Stars and ISM in Galactic Nuclei ", eds. T. Storchi-Bergmann, Luis Ho and H. R. Schmit

    Design of high-frequency Gm-C wavelet filters

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    “This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder." “Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.” DOI: 10.1109/ECCTD.2009.5274969A high-frequency wavelet filter which employs Gm-C blocks based on leap-frog (LF) multiple-loop feedback (MLF) structure is presented. The proposed method is well suitable for high-quality high-frequency operation since the Gm-C based filter can achieve high frequency, whilst LF MLF configuration has the characteristics of lower magnitude sensitivity and capability of realizing arbitrary rational functions. The Marr wavelet is selected as an example in this paper, and the design for a 100 MHz frequency operation is elaborated. The wavelet filter is simulated using TSMC 1.8 V 0.18 mum CMOS technology. Simulation results indicate that the proposed method is feasible for high frequency operation with relatively low power consumption.Peer reviewe

    A Generalization of Mathieu Subspaces to Modules of Associative Algebras

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    We first propose a generalization of the notion of Mathieu subspaces of associative algebras A\mathcal A, which was introduced recently in [Z4] and [Z6], to A\mathcal A-modules M\mathcal M. The newly introduced notion in a certain sense also generalizes the notion of submodules. Related with this new notion, we also introduce the sets σ(N)\sigma(N) and τ(N)\tau(N) of stable elements and quasi-stable elements, respectively, for all RR-subspaces NN of A\mathcal A-modules M\mathcal M, where RR is the base ring of A\mathcal A. We then prove some general properties of the sets σ(N)\sigma(N) and τ(N)\tau(N). Furthermore, examples from certain modules of the quasi-stable algebras [Z6], matrix algebras over fields and polynomial algebras are also studied.Comment: A new case has been added; some mistakes and misprints have been corrected. Latex, 31 page

    Gravitational-Wave Implications for the Parity Symmetry of Gravity at GeV Scale

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    Gravitational waves generated by the coalescence of compact binary open a new window to test the fundamental properties of gravity in the strong-field and dynamical regime. In this work, we focus on the parity symmetry of gravity which, if broken, can leave imprints on the waveform of gravitational wave. We construct generalized waveforms with amplitude and velocity birefringence due to parity violation in the effect field theory formalism, then analyze the open data of the ten binary black-hole merger events and the two binary neutron-star merger events detected by LIGO and Virgo collaboration. We do not find any signatures of violation of gravitational parity conservation, thereby setting the lower bound of the parity-violating energy scale to be 0.070.07 GeV. This presents the first observational evidence of the parity conservation of gravity at high energy scale, about 17 orders of magnitude tighter than the constraints from the Solar system tests and binary pulsar observation. The third-generation gravitational-wave detector is capable of probing the parity-violating energy scale at O(102)\mathcal{O}(10^2) GeV
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