486 research outputs found

    Media life

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    Review of the book 'Media Life' by Mark Deuze

    The physical state of selected cold clumps

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    Conclusions. The results indicate that most cold clumps, even those with dust color temperatures close to 11 K, are not necessarily prestellar.</p

    Doing time and motion diffractively: Academic life everywhere and all the time

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    This article offers a diffractive methodological intervention into workplace studies of academic life. In its engagement of a playful, performative research and writing practice the article speaks back to technocratic organisational and sociological workplace ‘time and motion’ studies which centre on the human and rational, and presume a linear teleology of cause and effect. As a counterpoint, we deploy posthumanist new materialist research practices which refuse human-centric approaches and aim to give matter its due. As a means to analyse what comes out of our joint workspaces photo project we produce two ‘passes’ through data – two diffractive experiments which destabilise what normally counts as ‘findings’ and their academic presentation. The article deploys the motif of ‘starting somewhere else’ to signal both our intention to keep data animated, alive and interactive, and to utilise visual and written modes of seriality as enabling constraints which produce a more generative focus on the mundane, emergent, unforeseen, and happenstance in studies of daily working life

    Breaking Open the Black Boxes: media archaeology, anarchaeology and media materiality

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    An essay on the emergent methodology of media archaeology, in relation to the material turn in approaches to digital media. In particular, this article advocates taking up Siegfried Zielinski's concept of 'anarchaeology', but in a different sense to the way it was originally proposed, in order to emphasise the political potentials of a media (an)archaeological methodological approach

    Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud

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    24 pags., 32 figs., 3 tabs.Context. The [CII] 158 μm far-infrared fine-structure line is one of the dominant cooling lines of the star-forming interstellar medium. Hence [CII] emission originates in and thus can be used to trace a range of ISM processes. Velocity-resolved large-scale mapping of [CII] in star-forming regions provides a unique perspective of the kinematics of these regions and their interactions with the exciting source of radiation. Aims. We explore the scientific applications of large-scale mapping of velocity-resolved [CII] observations. With the [CII] observations, we investigate the effect of stellar feedback on the ISM. We present the details of observation, calibration, and data reduction using a heterodyne array receiver mounted on an airborne observatory. Methods. A 1.15 square degree velocity-resolved map of the Orion molecular cloud centred on the bar region was observed using the German REceiver for Astronomy at Terahertz Frequencies (upGREAT) heterodyne receiver flying on board the Stratospheric Observatory for Infrared Astronomy. The data were acquired using the 14 pixels of the German REceiver for Astronomy at Terahertz Frequencies that were observed in an on-the-fly mapping mode. 2.4 million spectra were taken in total. These spectra were gridded into a three-dimensional cube with a spatial resolution of 14.1 arcseconds and a spectral resolution of 0.3 km s-1. Results. A square-degree [CII] map with a spectral resolution of 0.3 km s-1 is presented. The scientific potential of this data is summarized with discussion of mechanical and radiative stellar feedback, filament tracing using [CII], [CII] opacity effects, [CII] and carbon recombination lines, and [CII] interaction with the large molecular cloud. The data quality and calibration is discussed in detail, and new techniques are presented to mitigate the effects of unavoidable instrument deficiencies (e.g. baseline stability) and thus to improve the data quality. A comparison with a smaller [CII] map taken with the Herschel/Heterodyne Instrument for the Far-Infrared spectrometer is presented. Conclusions. Large-scale [CII] mapping provides new insight into the kinematics of the ISM. The interaction between massive stars and the ISM is probed through [CII] observations. Spectrally resolving the [CII] emission is necessary to probe the microphysics induced by the feedback of massive stars. We show that certain heterodyne instrument data quality issues can be resolved using a spline-based technique, and better data correction routines allow for more efficient observing strategies.This work is based on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc.(USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. This work is carried out within the Collaborative Research Centre 956, subproject [A4], funded by the Deutsche Forschungsgemeinschaft (DFG) – project ID 184018867. We thank the Spanish MICIU for funding support under grant AYA2017-85111-P

    Parameterizing the interstellar dust temperature

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    The temperature of interstellar dust particles is of great importance to astronomers. It plays a crucial role in the thermodynamics of interstellar clouds, because of the gas-dust collisional coupling. It is also a key parameter in astrochemical studies that governs the rate at which molecules form on dust. In 3D (magneto)hydrodynamic simulations often a simple expression for the dust temperature is adopted, because of computational constraints, while astrochemical modelers tend to keep the dust temperature constant over a large range of parameter space. Our aim is to provide an easy-to-use parametric expression for the dust temperature as a function of visual extinction (AVA_{\rm V}) and to shed light on the critical dependencies of the dust temperature on the grain composition. We obtain an expression for the dust temperature by semi-analytically solving the dust thermal balance for different types of grains and compare to a collection of recent observational measurements. We also explore the effect of ices on the dust temperature. Our results show that a mixed carbonaceous-silicate type dust with a high carbon volume fraction matches the observations best. We find that ice formation allows the dust to be warmer by up to 15% at high optical depths (AV>20A_{\rm V}> 20 mag) in the interstellar medium. Our parametric expression for the dust temperature is presented as Td=[11+5.7×tanh(0.61log10(AV))]χuv1/5.9T_{\rm d} = \left[ 11 + 5.7\times \tanh\bigl( 0.61 - \log_{10}(A_{\rm V})\bigr) \right] \, \chi_{\rm uv}^{1/5.9}, where χuv\chi_{\rm uv} is in units of the Draine (1978) UV fieldComment: 16 pages, 17 figures, 4 tables. Accepted for publication in A&A. Version 2: the omission of factor 0.921 in equation 4 is correcte

    The post-archival constellation: the archive under the technical conditions of computational media

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    In the present age, the archive is no longer hidden away in national librar- ies, museums, and darkened rooms, restricted in access and guarded by the modern-day equivalents of Jacques Derrida’s archons – the guardians of the archive.1 Indeed, researchers and archivists’ hermeneutic right and competence – and the power to interpret the archives – have been transformed with digitalization and the new technics of computational surfaces. Through computation, access to archives is made possible and often welcomed ‒ through rectangular screens that mediate the archives contents or through interfaces and visualizations that reanimate a previ- ously inert collectio
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