478 research outputs found

    Canonical Generations and the British Left: The Narrative Construction of the Miners’ Strike 1984–85

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    ‘Generations’ have been invoked to describe a variety of social and cultural relationships, and to understand the development of self-conscious group identity. Equally, the term can be an applied label and politically useful construct; generations can be retrospectively produced. Drawing on the concept of ‘canonical generations’ – those whose experiences come to epitomise an event of historic and symbolic importance – this article examines the narrative creation and functions of ‘generations’ as collective memory shapes and re-shapes the desire for social change. Building a case study of the canonical role of the miners’ strike of 1984–85 in the narrative history of the British left, it examines the selective appropriation and transmission of the past in the development of political consciousness. It foregrounds the autobiographical narratives of activists who, in examining and legitimising their own actions and prospects, (re)produce a ‘generation’ in order to create a relatable and useful historical understanding

    The SAMI Galaxy Survey: Revising the Fraction of Slow Rotators in IFS Galaxy Surveys

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    The fraction of galaxies supported by internal rotation compared to galaxies stabilized by internal pressure provides a strong constraint on galaxy formation models. In integral field spectroscopy surveys, this fraction is biased because survey instruments typically only trace the inner parts of the most massive galaxies. We present aperture corrections for the two most widely used stellar kinematic quantities V/σV/\sigma and λR\lambda_{R}. Our demonstration involves integral field data from the SAMI Galaxy Survey and the ATLAS3D^{\rm{3D}} Survey. We find a tight relation for both V/σV/\sigma and λR\lambda_{R} when measured in different apertures that can be used as a linear transformation as a function of radius, i.e., a first-order aperture correction. We find that V/σV/\sigma and λR\lambda_{R} radial growth curves are well approximated by second order polynomials. By only fitting the inner profile (0.5ReR_{\rm{e}}), we successfully recover the profile out to one ReR_{\rm{e}} if a constraint between the linear and quadratic parameter in the fit is applied. However, the aperture corrections for V/σV/\sigma and λR\lambda_{R} derived by extrapolating the profiles perform as well as applying a first-order correction. With our aperture-corrected λR\lambda_{R} measurements, we find that the fraction of slow rotating galaxies increases with stellar mass. For galaxies with logM/M>\log M_{*}/M_{\odot}> 11, the fraction of slow rotators is 35.9±4.335.9\pm4.3 percent, but is underestimated if galaxies without coverage beyond one ReR_{\rm{e}} are not included in the sample (24.2±5.324.2\pm5.3 percent). With measurements out to the largest aperture radius the slow rotator fraction is similar as compared to using aperture corrected values (38.3±4.438.3\pm4.4 percent). Thus, aperture effects can significantly bias stellar kinematic IFS studies, but this bias can now be removed with the method outlined here.Comment: Accepted for Publication in the Monthly Notices of the Royal Astronomical Society. 16 pages and 11 figures. The key figures of the paper are: 1, 4, 9, and 1

    The SAMI Galaxy Survey: energy sources of the turbulent velocity dispersion in spatially-resolved local star-forming galaxies

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    We investigate the energy sources of random turbulent motions of ionised gas from Hα\alpha emission in eight local star-forming galaxies from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. These galaxies satisfy strict pure star-forming selection criteria to avoid contamination from active galactic nuclei (AGN) or strong shocks/outflows. Using the relatively high spatial and spectral resolution of SAMI, we find that -- on sub-kpc scales our galaxies display a flat distribution of ionised gas velocity dispersion as a function of star formation rate (SFR) surface density. A major fraction of our SAMI galaxies shows higher velocity dispersion than predictions by feedback-driven models, especially at the low SFR surface density end. Our results suggest that additional sources beyond star formation feedback contribute to driving random motions of the interstellar medium (ISM) in star-forming galaxies. We speculate that gravity, galactic shear, and/or magnetorotational instability (MRI) may be additional driving sources of turbulence in these galaxies.Comment: 11 pages, 5 figures, 3 tables. Accepted by MNRA

    The SAMI Galaxy Survey: mass-kinematics scaling relations

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    We use data from the Sydney-AAO Multi-object Integral-field spectroscopy (SAMI) Galaxy Survey to study the dynamical scaling relation between galaxy stellar mass MM_* and the general kinematic parameter SK=KVrot2+σ2S_K = \sqrt{K V_{rot}^2 + \sigma^2} that combines rotation velocity VrotV_{rot} and velocity dispersion σ\sigma. We show that the logMlogSK\log M_* - \log S_K relation: (1)~is linear above limits set by properties of the samples and observations; (2)~has slightly different slope when derived from stellar or gas kinematic measurements; (3)~applies to both early-type and late-type galaxies and has smaller scatter than either the Tully-Fisher relation (logMlogVrot\log M_* - \log V_{rot}) for late types or the Faber-Jackson relation (logMlogσ\log M_* - \log\sigma) for early types; and (4)~has scatter that is only weakly sensitive to the value of KK, with minimum scatter for KK in the range 0.4 and 0.7. We compare SKS_K to the aperture second moment (the `aperture velocity dispersion') measured from the integrated spectrum within a 3-arcsecond radius aperture (σ3\sigma_{3^{\prime\prime}}). We find that while SKS_{K} and σ3\sigma_{3^{\prime\prime}} are in general tightly correlated, the logMlogSK\log M_* - \log S_K relation has less scatter than the logMlogσ3\log M_* - \log \sigma_{3^{\prime\prime}} relation.Comment: 14 pages, 8 figures, Accepted 2019 May 22. Received 2019 May 18; in original form 2019 January

    The SAMI Galaxy Survey: gravitational potential and surface density drive stellar populations -- I. early-type galaxies

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    The well-established correlations between the mass of a galaxy and the properties of its stars are considered evidence for mass driving the evolution of the stellar population. However, for early-type galaxies (ETGs), we find that gig-i color and stellar metallicity [Z/H] correlate more strongly with gravitational potential Φ\Phi than with mass MM, whereas stellar population age correlates best with surface density Σ\Sigma. Specifically, for our sample of 625 ETGs with integral-field spectroscopy from the SAMI Galaxy Survey, compared to correlations with mass, the color--Φ\Phi, [Z/H]--Φ\Phi, and age--Σ\Sigma relations show both smaller scatter and less residual trend with galaxy size. For the star formation duration proxy [α\alpha/Fe], we find comparable results for trends with Φ\Phi and Σ\Sigma, with both being significantly stronger than the [α\alpha/Fe]-MM relation. In determining the strength of a trend, we analyze both the overall scatter, and the observational uncertainty on the parameters, in order to compare the intrinsic scatter in each correlation. These results lead us to the following inferences and interpretations: (1) the color--Φ\Phi diagram is a more precise tool for determining the developmental stage of the stellar population than the conventional color--mass diagram; and (2) gravitational potential is the primary regulator of global stellar metallicity, via its relation to the gas escape velocity. Furthermore, we propose the following two mechanisms for the age and [α\alpha/Fe] relations with Σ\Sigma: (a) the age--Σ\Sigma and [α\alpha/Fe]--Σ\Sigma correlations arise as results of compactness driven quenching mechanisms; and/or (b) as fossil records of the ΣSFRΣgas\Sigma_{SFR}\propto\Sigma_{gas} relation in their disk-dominated progenitors.Comment: 9 pages, 4 figures, 1 table Accepted to Ap

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI)

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    We demonstrate a novel technology that combines the power of the multi-object spectrograph with the spatial multiplex advantage of an integral field spectrograph (IFS). The Sydney-AAO Multi-object IFS (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) that allows 13 imaging fibre bundles ("hexabundles") to be deployed over a 1-degree diameter field of view. Each hexabundle comprises 61 lightly-fused multimode fibres with reduced cladding and yields a 75 percent filling factor. Each fibre core diameter subtends 1.6 arcseconds on the sky and each hexabundle has a field of view of 15 arcseconds diameter. The fibres are fed to the flexible AAOmega double-beam spectrograph, which can be used at a range of spectral resolutions (R=lambda/delta(lambda) ~ 1700-13000) over the optical spectrum (3700-9500A). We present the first spectroscopic results obtained with SAMI for a sample of galaxies at z~0.05. We discuss the prospects of implementing hexabundles at a much higher multiplex over wider fields of view in order to carry out spatially--resolved spectroscopic surveys of 10^4 to 10^5 galaxies.Comment: 24 pages, 16 figures. Accepted by MNRA

    Beyond the island story? the opening ceremony of the London 2012 Olympic Games as public history

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    This paper evaluates the opening ceremony of the London 2012 Olympic Games as an exercise in public history. Public events have been widely identified within the study of nationalism as festivals that attempt to reinforce national identity and belonging. Contemporary Olympic Games figure in this literature as a specific form of event where the nature and content of a host state's identity is displayed for the global gaze of other nations. While opening ceremonies perform a rich display of national identity in any case, London 2012 is particularly significant for taking place at a time of major political contestation in the United Kingdom and has frequently been interpreted as an expression of radical patriotism. Traces of such patriotic thought associated particularly with England can be found in the opening ceremony's historical pageant and overall concept, showing resonances with the work of Raphael Samuel, who argued for a radical patriotism grounded in a multiplicity of accounts of the national past from many social positions. Depicting the nation through a multiplicity of biographical narratives produces a ‘mosaic' mode of representation which can be seen in other documentary and public history projects and in the political context of British public multiculturalism in the 2000s. This responds to the need for any national narrative to be composed through compressing the lives of millions of people into one coherent story, but complicates attempts to read a text such as the opening ceremony for what they ‘really' mean. A model for understanding narratives of the past as being produced in interaction between their initial creator(s) and their reader(s) is necessary for understanding not only the London 2012 opening ceremony in particular but public history and narratives of the national past in general

    Star-Forming, Rotating Spheroidal Galaxies in the GAMA and SAMI Surveys

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    The Galaxy And Mass Assembly (GAMA) survey has morphologically identified a class of ‘Little Blue Spheroid’ (LBS) galaxies whose relationship to other classes of galaxies we now examine in detail. Considering a sample of 868 LBSs, we find that such galaxies display similar but not identical colours, specific star formation rates, stellar population ages, mass-to-light ratios, and metallicities to Sd-Irr galaxies. We also find that LBSs typically occupy environments of even lower density than those of Sd-Irr galaxies, where ∼65 per cent of LBS galaxies live in isolation. Using deep, high-resolution imaging from VST KiDS and the new Bayesian, 2D galaxy profile modelling code PROFIT, we further examine the detailed structure of LBSs and find that their Sérsic indices, sizes, and axial ratios are compatible with those of low-mass elliptical galaxies. We then examine SAMI Galaxy survey integral field emission line kinematics for a subset of 62 LBSs and find that the majority (42) of these galaxies display ordered rotation with the remainder displaying disturbed/non-ordered dynamics. Finally, we consider potential evolutionary scenarios for a population with this unusual combination of properties, concluding that LBSs are likely formed by a mixture of merger and accretion processes still recently active in low-redshift dwarf populations. We also infer that if LBS-like galaxies were subjected to quenching in a rich environment, they would plausibly resemble cluster dwarf ellipticals
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