Highly-magnified, Multiply-imaged radio counterparts of the Sub-mm Starburst Emission in the Cluster-Lens MS0451.6-0305

Previous authors have reported the detection of intrinsically faint sub-mm emission lensed by the cluster MS0451.6-0305. They suggest that this emission arises from a merging system composed of a Ly-break galaxy and a pair of extremely red objects which are multiply-imaged in the optical/NIR observations. Since the submm emission presents an unusually large angular extent (~1 arcmin), the possible radio emission asociatted with that system can help to identify optical/NIR counterparts due to the higher spatial resolution and astrometric accuracy of the radio observations. Archive VLA data (BnA configuration at 1.4 GHz) was reduced and analysed. A simple lens model was constructed to aid the interpretation of the radio and pre-existing sub-mm and optical/NIR data. We present a 1.4 GHz map of the central region of MS0451.6-0305 and report the detection of gravitationally lensed radio emission, coincident with the previously discovered sub-mm lensed emission. The overall morphology and scale of the radio and sub-mm emission are strikingly similar, extending ~1 arcmin across the sky. This observation strongly suggests that the radio and sub-mm emission arise from the same sources. Preliminary estimates of the total S_850 microns/S_1.4 GHz flux density ratio appear to be consistent with that expected from distant star forming galaxies. The radio emission is resolved into 7 distinct components, and the overall structure can be explained, using a simple lens model, with three multiply-imaged radio sources at z~2.9. One of these sources is predicted to lie in the middle of the previously mentioned system in the source plane, suggesting that it is related to the intense star formation generated during the merging process.Comment: 11 pages, 3 figures. Acepted for publication in A&A on 05/10/200

Statistics of the Sunyaev-Zel'dovich Effect power spectrum

Using large numbers of simulations of the microwave sky, incorporating the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich (SZ) effect due to clusters, we investigate the statistics of the power spectrum at microwave frequencies between spherical multipoles of 1000 and 10000. From these virtual sky maps, we find that the spectrum of the SZ effect has a larger standard deviation by a factor of 3 than would be expected from purely Gaussian realizations, and has a distribution that is significantly skewed towards higher values, especially when small map sizes are used. The standard deviation is also increased by around 10 percent compared to the trispectrum calculation due to the clustering of galaxy clusters. We also consider the effects of including residual point sources and uncertainties in the gas physics. This has implications for the excess power measured in the CMB power spectrum by the Cosmic Background Imager and BIMA experiments. Our results indicate that the observed excess could be explained using a lower value of $\sigma_8$ than previously suggested, however the effect is not enough to match $\sigma_8=0.825$. The uncertainties in the gas physics could also play a substantial role. We have made our maps of the SZ effect available online.Comment: 21 pages, 23 figures, 3 tables. Accepted by MNRAS. We have made our maps of the SZ effect available onlin

La forêt et ses arbres : Réponse au commentaire d'Alain d'Iribarne

Adler Paul S., Borys Bryan. La forêt et ses arbres : Réponse au commentaire d'Alain d'Iribarne. In: Formation Emploi. N.21, 1988. pp. 30-31

Automatisation et travail : Le cas de la machine-outil

Paul S. Adler and Bryan Borys, Automatisierung und Arbeit : der Fall der Werkzeugmaschinen. Obwohl die durch die Einführung der NC-Werkzeugmaschinen veränderte Rolle des Operators oft als das Beispiel von Dequalifizierung angegeben wird, zeigt die Analyse der vorhandenen Daten, dass die Dequalifizierung kein verbreitetes und auf langer Sicht « rentables » Phänomen für das Unternehmen ist. Die Verfasser kritisieren und stellen einander gegenüber die verschiedenen seit ca. 30 Jahren geäusserten Ansätze von der « job evaluation » bis zu der « sozialen Bildung der Kompetenzen » über die « Dequalifizierungsthese ». Durch ihre kritische Prufung können die Autoren : ihren eigenen Standpunkt verteidigen und den Begriff der Automatisierung genauer formulieren ; den Zusammenhang zwischen Kompetenzen und die Charakteristika der Produktion herausstellen ; den Begriff der Kompetenz noch einmal uberdenken ; die Auswirkung der Spezialisierung der Arbeitsaufgaben auf die Kompetenzen wieder einschätzen und die grundsätzliche Unterscheidung zwischen kurz- und langfristigen Erscheinungen wieder einführen. Im Anschluss an den Aufsatz wird eine Debatte zwischen den Verfassern und Alain d'Iribarne veröffentlicht. Die Diskussion betrifft die Vorstellung des Gegenstandes der Analyse, die Möglichkeit, einen allgemeinen Trend der Entwicklung herauszustellen, und bestimmte besondere Faktoren wie die Beziehung zwischen Kompetenz und Lohn, die Wiederentdeckung des « Berufes », die Aufrechterhaltung der Grundkompetenzen des Fertigungsarbeiters.Paul S. Adler and Bryan Borys, Automation and work : Machine tools. Although the change in the operator's role linked to the introduction of numerical control machine tools is often quoted as the epitome of downgrading, examination of the available data shows that downgrading is not an extensive phenomenon in the firm, neither is it "profitable" in the long term. The authors criticise and compare the different approaches used in about the last thirty years, from "job evaluation" to "social building of skills", via "downgrading". This critical examination enables the authors to assert their own point of view and specify the concept of automation ; to bring to light the relationship between skills and characteristics of production ; to reconsider the concept of "skill" ; to re-evaluate the impact of task specialization on skills, and reintroduce the basic distinction between long and short term. A contradictory discussion between the authors and Alain d'Iribarne is published at the end of the article. The subject of this discussion is the conception of the subject analyzed and the possibility of distinguishing a general trend of development, and also certain special points, such as salary-skill relationships, rediscovery of craftsmanship, and the maintenance of the machine-tool operator's basic skills.Bien que le changement de rôle de l'opérateur lié à l'introduction des machines-outils à commande numérique soit souvent cité comme l'exemple même de la déqualification, un examen des données disponibles montre que la déqualification n'est pas un phénomène étendu et "rentable" à long terme pour l'entreprise. Les auteurs critiquent et confrontent les différentes approches exprimées depuis une trentaine d'années, depuis la "job evaluation" jusqu'à la "construction sociale des compétences" en passant par la "déqualification". Cet examen critique permet aux auteurs : d'affirmer leur propre point de vue et de préciser la notion d'automatisation ; de mettre en lumière la relation entre les compétences et les caractéristiques de la production ; de repenser le concept de compétence ; de réévaluer l'impact de la spécialisation des tâches sur les compétences et de réintroduire la distinction fondamentale entre court terme et long terme. Une discussion contradictoire entre les auteurs et Alain d'Iribarne est publiée à la suite de l'article. Cette discussion porte sur la conception de l'objet d'analyse et la possibilité de dégager une tendance générale d'évolution, ainsi que sur certains points particuliers tels que les relations entre les compétences et les salaires, la redécouverte du métier, le maintien des compétences de base de l'usineur.Adler Paul S., Borys Bryan. Automatisation et travail : Le cas de la machine-outil. In: Formation Emploi. N.21, 1988. pp. 5-25