217 research outputs found

    ‘A question of equality and choice’: same-sex couples’ attitudes towards civil partnership after the introduction of same-sex marriage

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    Since the introduction of same-sex marriage, there have been two parallel institutions (marriage and civil partnership) for the legal recognition of same-sex relationships in England, Wales and Scotland. The current study aimed to examine how those in a civil partnership or a same-sex marriage perceive civil partnership in the context of marriage equality. Eighty-two respondents completed a qualitative online survey, and their responses were analysed thematically. The respondents were divided between those who viewed civil partnership as: 1) a stepping stone to equality, and felt that civil partnerships should be discontinued; 2) a form of legal recognition free from cultural baggage, and argued the Government should make civil partnership available for all; or 3) those who displayed ambivalence and conflicting views. We conclude by discussing how the principle of formal equality underpinned opinions on all sides, and what implications this might have for how we understand discrimination

    jFuzzyLogic: a Java Library to Design Fuzzy Logic Controllers According to the Standard for Fuzzy Control Programming

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    Fuzzy Logic Controllers are a specific model of Fuzzy Rule Based Systems suitable for engineering applications for which classic control strategies do not achieve good results or for when it is too difficult to obtain a mathematical model. Recently, the International Electrotechnical Commission has published a standard for fuzzy control programming in part 7 of the IEC 61131 norm in order to offer a well defined common understanding of the basic means with which to integrate fuzzy control applications in control systems. In this paper, we introduce an open source Java library called jFuzzyLogic which offers a fully functional and complete implementation of a fuzzy inference system according to this standard, providing a programming interface and Eclipse plugin to easily write and test code for fuzzy control applications. A case study is given to illustrate the use of jFuzzyLogic.McGill Uninversity, Genome QuebecSpanish Government TIN2011-28488Andalusian Government P10-TIC-685

    Anatomy of a post-starburst minor merger: a multi-wavelength WFC3 study of NGC 4150

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    (Abridged) We present a spatially-resolved near-UV/optical study of NGC 4150, using the Wide Field Camera 3 (WFC3) on board the Hubble Space Telescope. Previous studies of this early-type galaxy (ETG) indicate that it has a large reservoir of molecular gas, exhibits a kinematically decoupled core (likely indication of recent merging) and strong, central H_B absorption (indicative of young stars). The core of NGC 4150 shows ubiquitous near-UV emission and remarkable dusty substructure. Our analysis shows this galaxy to lie in the near-UV green valley, and its pixel-by-pixel photometry exhibits a narrow range of near-UV/optical colours that are similar to those of nearby E+A (post-starburst) galaxies. We parametrise the properties of the recent star formation (age, mass fraction, metallicity and internal dust content) in the NGC 4150 pixels by comparing the observed near-UV/optical photometry to stellar models. The typical age of the recent star formation (RSF) is around 0.9 Gyrs, consistent with the similarity of the near-UV colours to post-starburst systems, while the morphological structure of the young component supports the proposed merger scenario. The RSF metallicity, representative of the metallicity of the gas fuelling star formation, is around 0.3 - 0.5 Zsun. Assuming that this galaxy is a merger and that the gas is sourced mainly from the infalling companion, these metallicities plausibly indicate the gas-phase metallicity (GPM) of the accreted satellite. Comparison to the local mass-GPM relation suggests (crudely) that the mass of the accreted system is around 3x10^8 Msun, making NGC 4150 a 1:20 minor merger. A summation of the pixel RSF mass fractions indicates that the RSF contributes about 2-3 percent of the stellar mass. This work reaffirms our hypothesis that minor mergers play a significant role in the evolution of ETGs at late epochs.Comment: 28 pages, 2 tables, accepted for publication in Ap

    Black Hole Growth in Disk Galaxies Mediated by the Secular Evolution of Short Bars

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    The growth of black holes (BHs) in disk galaxies lacking classical bulges, which implies an absence of significant mergers, appears to be driven by secular processes. Short bars of sub-kiloparsec radius have been hypothesized to be an important mechanism for driving gas inflows to small scale, feeding central BHs. In order to quantify the maximum BH mass allowed by this mechanism, we examine the robustness of short bars to the dynamical influence of BHs. Large-scale bars are expected to be robust, long-lived structures; extremely massive BHs, which are rare, are needed to completely destroy such bars. However, we find that short bars, which are generally embedded in largescale outer bars, can be destroyed quickly when BHs of mass Mbh ∼ 0.05% 0.2% of the total stellar mass (M∗) are present. In agreement with this prediction, all galaxies observed to host short bars have BHs with a mass fraction less than 0.2% M∗. Thus, the dissolution of short inner bars is possible, perhaps even frequent, in the universe. An important implication of this result is that inner-bar-driven gas inflows may be terminated when BHs grow to ∼0.1% M∗. We predict that 0.2% M∗ is the maximum mass of BHs allowed if they are fed predominately via inner bars. This value matches well the maximum ratio of BH-to-host-galaxy stellar mass observed in galaxies with pseudo-bulges and most nearby active galactic nucleus host galaxies. This hypothesis provides a novel explanation for the lower M Mbh in galaxies that have avoided significant mergers compared with galaxies with classical bulges

    The Fueling and Evolution of AGN: Internal and External Triggers

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    In this chapter, I review the fueling and evolution of active galactic nuclei (AGN) under the influence of internal and external triggers, namely intrinsic properties of host galaxies (morphological or Hubble type, color, presence of bars and other non-axisymmetric features, etc) and external factors such as environment and interactions. The most daunting challenge in fueling AGN is arguably the angular momentum problem as even matter located at a radius of a few hundred pc must lose more than 99.99 % of its specific angular momentum before it is fit for consumption by a BH. I review mass accretion rates, angular momentum requirements, the effectiveness of different fueling mechanisms, and the growth and mass density of black BHs at different epochs. I discuss connections between the nuclear and larger-scale properties of AGN, both locally and at intermediate redshifts, outlining some recent results from the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte

    A multivariate statistical analysis of spiral galaxy luminosities. I. Data and results

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    We have performed a multiparametric analysis of luminosity data for a sample of 234 normal spiral and irregular galaxies observed in X-rays with the {\it Einstein Observatory}. This sample is representative of S and Irr galaxies, with a good coverage of morphological types and absolute magnitudes. In addition to X-ray and optical da ta, we have compiled H-band magnitudes, IRAS near- and far-infrared, and 6cm radio co ntinuum observations for the sample from the literature. We have also performed a carefu l compilation of distance estimates. We have explored the effect of morphology by dividing the sample into early (S0/a-Sab), intermediate (Sb-Sbc), and late-type (Sc-Irr) subsamples. The data were analysed with bivariate and multiv ariate survival analysis techniques that make full use of all the information available in both detections and limits

    An HST Survey of the mid-UV Morphology of Nearby Galaxies

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    (Abbreviated) We present an imaging survey of 37 nearby galaxies observed with HST/WFPC2 in the mid-UV F300W filter and in F814W. 11 galaxies were also imaged in F255W. These galaxies were selected to be detectable with WFPC2 in one orbit, and cover a wide range of Hubble types and inclinations. The mid-UV spans the gap between our groundbased optical/NIR images and far-UV images available from the Astro/UIT missions. Our first qualitative results are: (1) Early-type galaxies show a significant decrease in surface brightness going from the red to the mid-UV, and in some cases the presence of dust lanes. Some galaxies would be classified different when viewed in the mid-UV, some become dominated by a blue nuclear feature or point source. (2) Half of the mid-type spiral and star-forming galaxies appear as a later morphological type in the mid-UV, as Astro/UIT also found in the far-UV. Some- times these differences are dramatic. The mid-UV images show a considerable range in the scale and surface brightness of individual star-forming regions. Almost all mid-type spirals have their small bulges bi-sected by a dust-lane. (3) Most of the heterogeneous subset of late-type, irregular, peculiar, and merging galaxies display F300W morphologies that are similar to those seen in F814W, but with differences due to recognizable dust features absorbing the bluer light, and due to UV-bright hot stars, star-clusters, and star-forming ridges. In the rest-frame mid-UV, early- to mid-type galaxies are more likely to be misclassified as later types than vice versa. This morphological K-correction explains only part of the excess faint blue galaxies seen in deep HST fields.Comment: 30 pages, LateX (AASTeX5.0), 2 figures and 3 tables included, mid-UV atlas and pan-chromatic atlas provided as 63 JPG figures. Full resolution PS version (~100Mb) available upon request. Accepted for publication in ApJ

    A review of elliptical and disc galaxy structure, and modern scaling laws

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    A century ago, in 1911 and 1913, Plummer and then Reynolds introduced their models to describe the radial distribution of stars in `nebulae'. This article reviews the progress since then, providing both an historical perspective and a contemporary review of the stellar structure of bulges, discs and elliptical galaxies. The quantification of galaxy nuclei, such as central mass deficits and excess nuclear light, plus the structure of dark matter halos and cD galaxy envelopes, are discussed. Issues pertaining to spiral galaxies including dust, bulge-to-disc ratios, bulgeless galaxies, bars and the identification of pseudobulges are also reviewed. An array of modern scaling relations involving sizes, luminosities, surface brightnesses and stellar concentrations are presented, many of which are shown to be curved. These 'redshift zero' relations not only quantify the behavior and nature of galaxies in the Universe today, but are the modern benchmark for evolutionary studies of galaxies, whether based on observations, N-body-simulations or semi-analytical modelling. For example, it is shown that some of the recently discovered compact elliptical galaxies at 1.5 < z < 2.5 may be the bulges of modern disc galaxies.Comment: Condensed version (due to Contract) of an invited review article to appear in "Planets, Stars and Stellar Systems"(www.springer.com/astronomy/book/978-90-481-8818-5). 500+ references incl. many somewhat forgotten, pioneer papers. Original submission to Springer: 07-June-201
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