30 research outputs found

    GLAST: Understanding the High Energy Gamma-Ray Sky

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    We discuss the ability of the GLAST Large Area Telescope (LAT) to identify, resolve, and study the high energy gamma-ray sky. Compared to previous instruments the telescope will have greatly improved sensitivity and ability to localize gamma-ray point sources. The ability to resolve the location and identity of EGRET unidentified sources is described. We summarize the current knowledge of the high energy gamma-ray sky and discuss the astrophysics of known and some prospective classes of gamma-ray emitters. In addition, we also describe the potential of GLAST to resolve old puzzles and to discover new classes of sources.Comment: To appear in Cosmic Gamma Ray Sources, Kluwer ASSL Series, Edited by K.S. Cheng and G.E. Romer

    Accreting Black Holes

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    This chapter provides a general overview of the theory and observations of black holes in the Universe and on their interpretation. We briefly review the black hole classes, accretion disk models, spectral state classification, the AGN classification, and the leading techniques for measuring black hole spins. We also introduce quasi-periodic oscillations, the shadow of black holes, and the observations and the theoretical models of jets.Comment: 41 pages, 18 figures. To appear in "Tutorial Guide to X-ray and Gamma-ray Astronomy: Data Reduction and Analysis" (Ed. C. Bambi, Springer Singapore, 2020). v3: fixed some typos and updated some parts. arXiv admin note: substantial text overlap with arXiv:1711.1025

    Mobilities of Knowledge: An Introduction

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    Mobilities of Knowledge examines how geographical mobility of people and (im)material things has impacted epistemic systems of knowledge in different historical and geographical contexts. In this chapter, the authors introduce concepts and debates in interdisciplinary research on spatial mobility and the production, dissemination, and transfer of knowledge. They suggest extending Urry’s (2007) typology of interdependent mobilities that constitute the space of flows and the space of places (Castells, 1996) from five to six dimensions through the consideration of mobile knowledges, concepts, and practices. Finally, they outline how the chapters of this volume help to identify generic as well as context-specific practices and processes of knowledge production, dissemination, and transfer and call for more empirical case studies to further the collective development of flexible conceptual understandings

    Seeing Red:A Political Economy of Digital Memory

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    This article intervenes into research on cultural and digital memory by arguing for the significance of the materiality of memory and its underlying political economy. Although cultural and digital memories are characterized as contested, multiple and often involving interplay and conflict between different power dynamics, what remains missing is an understanding of the material basis of digital, globally connective memory or what is termed here ‘globital memory’. In work on memory which addresses social and mobile technologies there is an emphasis on the transition from collective to ‘connective memory’ and the ways in which social media offer possibilities for the articulation of marginalized memories, as well as new forms of archiving. While current concern is signalling a return to the question of the significance of ‘mass media’ in relation to social and mobile media and digital memory, this work does not yet address the political economy of ‘globital’ memory which includes the underlying materiality and technical infrastructure of social media. Using the conceptual metaphor of mining memories, the article will attend to what lies beneath the ‘digital skin’ of memories on social networks such as YouTube. I address the socioeconomic and technical infrastructures that enable the capture, circulation and storage of data that then become the raw material of globital memory

    Double Boundary and Cosmopolitan Experience in Europe

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    This contribution aims to open up the debate about national, European and cosmopolitan identity through an interpretation of Simmel’s double boundary dialectic: human beings are boundaries and only those who stand outside their boundaries can see them as such. One difficulty with defining oneself as European stems from what could be called the “double Other” (intra- and extra-European) diachronic recognition process. Exploring the possible/impossible cosmopolitan meta-synthesis can identify certain traits of the cosmopolitan experience in Europe.Peer reviewe
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