496 research outputs found

    Books and codices. Transculturation, language dissemination and education in the works of friar Pedro de Gante

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    The present study analyses the work of Flemish Franciscan missionary fray Pedro de Gante (1480-1572) against the background of the early stages of the evangelization in New Spain, modern-day Mexico. By means of his works the Catecismo en Pictogramas [ca.1527], the Doctrina Christiana en Lengua Mexicana [1547] and the Cartilla para enseñar a leer [1569] Gante played a fundamental role in the processes of transculturation playing out between European missionaries and the Nahua populations of the Valley of Mexico. The role of Gante as a transcendental figure of cultural contact has been often neglected; previous studies on the subject have only focused on general aspects of Gante’s biography. A thorough, comparative study of Gante’s works that ingrains them in the wider context of the early years of the evangelization (1524-1572) has never been done before. The present work aims to fill this void. The important role Gante and his works played in the process of transculturation is demonstrated through an interdisciplinary contextual framework that employs agency theory, New Philology, Colonial semiosis and annales theory. This study shows that Gante’s works represent the initial stages of a translation process in which Christian doctrine was converted into Nahuatl. This process was by no means straightforward and involved the translation of an entire set of cultural and cosmological referents from one system of beliefs to another. Gante’s works are at the forefront of this development and this research demonstrates clearly how Gante developed, drawing on his unique cultural and social background, novel evangelical strategies which involved the active participation of both missionaries and the Nahuas themselves. The significance of this, cannot be overlooked, with the translation Gante started an open-dialogue with the Nahuas. Showing that the evangelization of Mexico was not a simple process of imposition, but a complex process in which the different elements of society had a voice and accommodated and negated the influence of the other while constructing new cultural categories

    Accurate and efficient waveforms for compact binaries on eccentric orbits

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    Compact binaries that emit gravitational waves in the sensitivity band of ground-based detectors can have non-negligible eccentricities just prior to merger, depending on the formation scenario. We develop a purely analytic, frequency-domain model for gravitational waves emitted by compact binaries on orbits with small eccentricity, which reduces to the quasi-circular post-Newtonian approximant TaylorF2 at zero eccentricity and to the post-circular approximation of Yunes et al. (2009) at small eccentricity. Our model uses a spectral approximation to the (post-Newtonian) Kepler problem to model the orbital phase as a function of frequency, accounting for eccentricity effects up to O(e8){\cal{O}}(e^8) at each post-Newtonian order. Our approach accurately reproduces an alternative time-domain eccentric waveform model for eccentricities e[0,0.4]e\in [0, 0.4] and binaries with total mass less than 12 solar masses. As an application, we evaluate the signal amplitude that eccentric binaries produce in different networks of existing and forthcoming gravitational waves detectors. Assuming a population of eccentric systems containing black holes and neutron stars that is uniformly distributed in co-moving volume, we estimate that second generation detectors like Advanced LIGO could detect approximately 0.1-10 events per year out to redshift z0.2z\sim 0.2, while an array of Einstein Telescope detectors could detect hundreds of events per year to redshift z2.3z \sim 2.3.Comment: 12 pages, 6 figures, 1 appendix. Submitted to Phys. Rev. D. v2: affiliations updated, one reference corrected. Accepted to Phys. Rev.

    Bumpy Black Holes in Alternate Theories of Gravity

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    We generalize the bumpy black hole framework to allow for alternative theory deformations. We construct two model-independent parametric deviations from the Kerr metric: one built from a generalization of the quasi-Kerr and bumpy metrics and one built directly from perturbations of the Kerr spacetime in Lewis-Papapetrou form. We find the conditions that these "bumps" must satisfy for there to exist an approximate second-order Killing tensor so that the perturbed spacetime still possesses three constants of the motion (a deformed energy, angular momentum and Carter constant) and the geodesic equations can be written in first-order form. We map these parameterized metrics to each other via a diffeomorphism and to known analytical black hole solutions in alternative theories of gravity. The parameterized metrics presented here serve as frameworks for the systematic calculation of extreme-mass ratio inspiral waveforms in parameterized non-GR theories and the investigation of the accuracy to which space-borne gravitational wave detectors can constrain such deviations.Comment: 17 pages, replaced with version published in Phys. Rev.

    Relativistic Effects in Extreme Mass Ratio Gravitational Wave Bursts

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    Extreme mass ratio bursts (EMRBs) have been proposed as a possible source for future space-borne gravitational wave detectors, such as the Laser Interferometer Space Antenna (LISA). These events are characterized by long-period, nearly-radial orbits of compact objects around a central massive black hole. The gravitational radiation emitted during such events consists of a short burst, corresponding to periapse passage, followed by a longer, silent interval. In this paper we investigate the impact of including relativistic corrections to the description of the compact object's trajectory via a geodesic treatment, as well as including higher-order multipole corrections in the waveform calculation. The degree to which the relativistic corrections are important depends on the EMRB's orbital parameters. We find that relativistic EMRBs (v_{max}}/c > 0.25) are not rare and actually account for approximately half of the events in our astrophysical model. The relativistic corrections tend to significantly change the waveform amplitude and phase relative to a Newtonian description, although some of this dephasing could be mimicked by parameter errors. The dephasing over several bursts could be of particular importance not only to gravitational wave detection, but also to parameter estimation, since it is highly correlated to the spin of the massive black hole. Consequently, we postulate that if a relativistic EMRB is detected, such dephasing might be used to probe the relativistic character of the massive black hole and obtain information about its spin.Comment: 13 pages, 8 figures, 2 tables. Replaced with version accepted for publication in the Ap.

    Black hole sensitivities in Einstein-scalar-Gauss-Bonnet gravity

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    The post-Newtonian dynamics of black hole binaries in Einstein-scalar-Gauss-Bonnet theories of gravity depends on the so-called "sensitivities", quantities which characterize a black hole's adiabatic response to the time-dependent scalar field environment sourced by its companion. In this work, we calculate numerically the sensitivities of nonrotating black holes, including spontaneously scalarized ones, in three classes of Einstein-scalar-Gauss-Bonnet gravity: the shift-symmetric, dilatonic and Gaussian theories. When possible, we compare our results against perturbative analytical results, finding excellent agreement. Unlike their general relativistic counterparts, black holes in Einstein-scalar-Gauss-Bonnet gravity only exist in a restricted parameter space controlled by the theory's coupling constant. A preliminary study of the role played by the sensitivities in black hole binaries suggests that, in principle, black holes can be driven outside of their domain of existence during the inspiral, for binary parameters which we determine

    Cross section, final spin and zoom-whirl behavior in high-energy black hole collisions

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    We study the collision of two highly boosted equal mass, nonrotating black holes with generic impact parameter. We find such systems to exhibit zoom-whirl behavior when fine tuning the impact parameter. Near the threshold of immediate merger the remnant black hole Kerr parameter can be near maximal (a/M about 0.95) and the radiated energy can be as large as 35% of the center-of-mass energy.Comment: Rearranged results section; accepted for publication in Phys. Rev. Let

    Asymptotically Matched Spacetime Metric for Non-Precessing, Spinning Black Hole Binaries

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    We construct a closed-form, fully analytical 4-metric that approximately represents the spacetime evolution of non-precessing, spinning black hole binaries from infinite separations up to a few orbits prior to merger. We employ the technique of asymptotic matching to join a perturbed Kerr metric in the neighborhood of each spinning black hole to a near-zone, post-Newtonian metric farther out. The latter is already naturally matched to a far-zone, post-Minkowskian metric that accounts for full temporal retardation. The result is a 4-metric that is approximately valid everywhere in space and in a small bundle of spatial hypersurfaces. We here restrict our attention to quasi- circular orbits, but the method is valid for any orbital motion or physical scenario, provided an overlapping region of validity or buffer zone exists. A simple extension of such a metric will allow for future studies of the accretion disk and jet dynamics around spinning back hole binaries
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