1,744 research outputs found

    The hunt for red AGN: a new infrared diagnostic

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    We introduce a new infrared diagnostic to separate galaxies on the basis of their dominant infrared emission: stellar or nuclear. The main novelty with respect to existing diagnostics, is the usage of a broad band encompassing at the same time the 9.7micron Silicate absorption feature and one of the adjacent broad PAH (polycyclic aromatic hydrocarbon) features. This provides a robust estimate of the near- to mid-infrared continuum slope and enables a clear distinction among different classes of galaxies up to a redshift z=2.5. The diagnostic can be applied to a wealth of archival data from the ISO, Spitzer, and Akari surveys as well as future JWST surveys. Based on data in the GOODS, Lockman Hole, and North Ecliptic Pole (NEP) fields, we find out that approximately 70% active galactic nuclei detected with X-ray and optical spectroscopy dominate the total mid-infrared emission. Finally, we estimate that AGN contribute less than 30% of the mid-infrared extragalactic integrated emission.Comment: 5 pages, 4 figures, accepted for publication in MNRA

    Self-Recognition in Data Visualization: How People See Themselves in Social Visualizations

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    Self-recognition is an intimate act performed by people. Inspired by Paul Ricoeur, we reflect upon the action of self-recognition, especially when data visualization represents the observer itself. Along the article, the reader is invited to think about this specific relationship through concepts like the personal identity stored in information systems, the truthfulness at the core of self-recognition, and the mutual-recognition among community members. In the context of highly interdisciplinary research, we unveil two protagonists in data visualization: the designer and the observer - the designer as the creator and the observer as the viewer of a visualization. This article deals with some theoretical aspects behind data visualization, a discipline more complex than normally expected. We believe that data visualization deserves a conceptual framework, and this investigation pursues this intention. For this reason, we look at the designer as not just a technician in the visualization production, but as a contemporary ethnologist - the designer as a professional working in a social environment to comprehend the context and formulate a specific inquiry with the help of appropriate visual languages

    CREATING ORGANIZATIONAL PARTICIPATIVE INNOVATION: EXPLOITING THE POWER OF ORGANIZATIONAL DYNAMIC LANDSCAPES

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    This paper explores the ways an organizational network should reflect upon its communicative processes and its responsible and decision making management. As regards the emergency interventions of the Civil Defence, the communication concerns the following: the selection and the taking charge of the information, the coordination on the spot, widespread procedures and local knowledge of the working practices. The central issue is how to define a participative way for the shared realization of an organizational network description, seen as a dynamic landscape. The various forms of knowledge embedded in the heterogeneous network organizations could be translated into landscapes, starting with paper based design games and finishing with a collective participation of a dramatic performance, sharing different but necessarily coexisting interpretations of the interventions. The paper describes this reflective path, divided into three workshops: the first workshop concerns the definition of the network boundaries and its components; the second workshop regards the shared description of two noteworthy interventions; the third workshop is about the immersion in a controlroom, as the ideal stage for a participative representation of an emergency. It concludes with a proposal of a landscape design, a knowledge enriched version of an Event Trace Diagram, constructed as a prototype starting from the recordings of the performance in the control room. Furthermore the paper suggests the possibility of a digital coordination place, as a kind of a 2.0 dashboard collaboration tool

    ISOPHOT 95 micron observations in the Lockman Hole - The catalogue and an assessment of the source counts

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    We report results from a new analysis of a deep 95 micron imaging survey with ISOPHOT on board the Infrared Space Observatory, over a ~1 square degree area within the Lockman Hole, which extends the statistics of our previous study (Rodighiero et al. 2003). Within the survey area we detect sixty-four sources with S/N>3 (roughly corresponding to a flux limit of 16 mJy). Extensive simulations indicate that the sample is almost complete at fluxes > 100 mJy, while the incompleteness can be quantified down to ~30 mJy. The 95 micron galaxy counts reveal a steep slope below 100 mJy (alpha~1.6), in excess of that expected for a non-evolving source population. In agreement with counts data from ISO at 15 and 175 micron, this favours a model where the IR populations evolve both in number and luminosity densities. We finally comment on some differences found with other ISO results in this area.Comment: 4 pages, accepted by Astronomy and Astrophysics Lette

    Ars Memorativa as the Genesis of Information Design:A Conversation with Manuel Lima

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    Manuel Lima is one of the most prominent figures of data visualization since the publication of Visual Complexity (Lima 2011). In this conversation, Manuel Lima traces back the origin of data visualization to Ars Memorativa, an ancient mnemonic technique to organize information and facilitate its recall. Going back to the origins is an obsession that brought him to collect and arrange into books images of information design from both physical and digital archives. By doing this, Manuel Lima tackled issues related to the digital objects and their creation, use, and preservation, with a point of view capable of combining the passion for visualizing information and the profession of UX design. This conversation, which took place between Lisbon and Milan on Wednesday 28 July, 2021, comes from a blurb that Manuel Lima wrote for Mapping Affinities (Rodighiero 2021). The discussion is part of the project From Data to Wisdom, and is supported by Fundação para a Ciência e a Tecnologia through the grant POCI-01-0145-FEDER-029717, and the Swiss National Science Foundation through the grant 194442. This text, originally created for the forthcoming book From Data to Wisdom (Higuera Rubio et al. 2022), is published as a preview for Nightingale, the journal of the Data Visualization Society

    Extending museum beyond physical space:A Data-Driven Study of Aldo Rossi's Analogous City as a Mobile Museum Object

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    Aldo Rossi composed the famous collage known as Analogous City for the Venice Biennale in 1976. This text presents a visual study of the collage through both physical and digital means: a mobile app works in conjunction with a reprint of the Analogous City in the format of a city map. Forty years after its creation, the collage’s original elements are finally identified and collected, and the mechanisms of composition are disclosed thanks to Fabio Reinhart’s contribution. The map of the Analogous City is analyzed in both historical and museum viewpoints, focusing on the reflections that emerged when exhibiting in Maastricht, Milan, Lausanne, Bergamo, and Rome. Although the map was designed as an interactive installation for these exhibitions, it has turned out to be also an educational tool useful outside museums. If Aldo Rossi created an artwork to think about the reconstruction of the city, likewise, the map of the Analogous City helps to rethink museums by designing their objects in a way they can leave the exhibition for a second life in the city

    Extragalactic Source Counts in the Spitzer 24-micron Band: What Do We Expect From ISOCAM 15-micron Data and Models?

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    The comparison between the new Spitzer data at 24 micron and the previous ISOCAM data at 15 micron is a key tool to understand galaxy properties and evolution in the infrared and to interpret the observed number counts, since the combination of Spitzer with the ISO cosmological surveys provides for the first time the direct view of the Universe in the Infrared up to z~2. We present the prediction in the Spitzer 24-micron band of a phenomenological model for galaxy evolution derived from the 15-micron data. Without any ``a posteriori'' update, the model predictions seem to agree well with the recently published 24-micron extragalactic source counts, suggesting that the peak in the 24-micron counts is dominated by ``starburst'' galaxies like those detected by ISOCAM at 15 micron, but at higher redshifts (1 < z < 2 instead of 0.5 < z < 1.5).Comment: 8 pages: 4 pages of main text + 5 postscript figures, use aastex. Accepted for publication in ApJL. Replaced with the proof version (added missing references and corrected a few sentences
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