28,725 research outputs found

    Strange stars at finite temperature

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    We calculate strange star properties, using large N_c approximation with built-in chiral symmetry restoration (CSM). We used a relativistic Hartree Fock mean field approximation method, using a modified Richardson potential with two scale parameters \Lambda and \Lambda^\prime, to find a new set of equation of states for strange quark matter. We take the effect of temperature (T) on gluon mass, in addition to the usual density dependence, and find that the transition T from hadronic matter to strange matter is 80 MeV. Therefore formation of strange stars may be the only signal for formation of QGP with asymptotic freedom and CSM.Comment: To be published in the proceedings of The Third 21COE Symposium, held at Department of Physics, Waseda University, Tokyo, Japan, September 1-3, 200

    Does monetary policy have differential state-level effects? an empirical evaluation

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    The paper examines whether monetary policy has similar effects across major states in the Indian polity. Impulse response functions from an estimated Structural Vector Auto Regression (SVAR) reveal two sets of states: a core of states that respond to monetary policy in a significant fashion vis-à-vis others whose response is less significant. The paper attempts to trace the reasons for the differential response of these two sets of states in terms of financial deepening and differential industry mix.monetary policy; regional effect; optimum currency area

    The Formal Underpinnings of the Response Functions used in X-Ray Spectral Analysis

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    This work provides an in-depth mathematical description of the response functions that are used for spatial and spectral analysis of X-ray data. The use of such functions is well-known to anyone familiar with the analysis of X-ray data where they may be identified with the quantities contained in the Ancillary Response File (ARF), the Redistribution Matrix File (RMF), and the Exposure Map. Starting from first-principles, explicit mathematical expressions for these functions, for both imaging and dispersive modes, are arrived at in terms of the underlying instrumental characteristics of the telescope including the effects of pointing motion. The response functions are presented in the context of integral equations relating the expected detector count rate to the source spectrum incident upon the telescope. Their application to the analysis of several source distributions is considered. These include multiple, possibly overlapping, and spectrally distinct point sources, as well as extended sources. Assumptions and limitations behind the usage of these functions, as well as their practical computation are addressed.Comment: 22 pages, 3 figures (LaTeX

    HST Observations of Gravitationally Lensed Features in the Rich Cluster Ac114

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    Deep Hubble Space Telescope images of superlative resolution obtained for the distant rich cluster AC114 (z=0.31) reveal a variety of gravitational lensing phenomena for which ground-based spectroscopy is available. We present a luminous arc which is clearly resolved by HST and appears to be a lensed z=0.64 sub-L star spiral galaxy with a detected rotation curve. Of greatest interest is a remarkably symmetrical pair of compact blue images separated by 10 arcsec and lying close to the cluster cD. We propose that these images arise from a single very faint background source gravitationally lensed by the cluster core. Deep ground-based spectroscopy confirms the lensing hypothesis and suggests the source is a compact star forming system at a redshift z=1.86. Taking advantage of the resolved structure around each image and their very blue colours, we have identified a candidate third image of the same source roughly 50 arcsec away. The angular separation of the three images is much larger than previous multiply-imaged systems and indicates a deep gravitational potential in the cluster centre. Resolved multiply-imaged systems, readily recognised with HST, promise to provide unique constraints on the mass distribution in the cores of intermediate redshift clusters.Comment: submitted to ApJ, 6 pages (no figures), uuencoded Postscript, compressed TAR of Postscript figures available via anonymous ftp in users/irs/figs/ac114_figs.tar.gz on astro.caltech.edu. PAL-IRS-

    On the Influence of Stochastic Moments in the Solution of the Neutron Point Kinetics Equation

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    On the Influence of Stochastic Moments in the Solution of the Neutron Point Kinetics EquationComment: 12 pages, 2 figure
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