Planck \u27s Dusty GEMS: VII. Atomic carbon and molecular gas in dusty starburst galaxies at z = 2 to 4

The bright 3 P 1 - 3 P 0 ([CI] 1-0) and 3 P 2 - 3 P 1 ([CI] 2-1) lines of atomic carbon are becoming more and more widely employed as tracers of the cold neutral gas in high-redshift galaxies. Here we present observations of these lines in the 11 galaxies of the set of Planck\u27s Dusty GEMS, the brightest gravitationally lensed galaxies on the extragalactic submillimeter sky probed by the Planck satellite. We have [CI] 1-0 and [CI] 2-1 measurements for seven and eight of these galaxies, respectively, including four galaxies where both lines have been measured. We use our observations to constrain the gas excitation mechanism, excitation temperatures, optical depths, atomic carbon and molecular gas masses, and carbon abundances. Ratios of L CI /L FIR are similar to those found in the local universe, and suggest that the total cooling budget through atomic carbon has not significantly changed in the last 12 Gyr. Both lines are optically thin and trace 1 - 6 7 10 7 M of atomic carbon. Carbon abundances, X CI , are between 2.5 and 4 7 10 -5 , for an ultra-luminous infrared galaxy (ULIRG) CO-to-H 2 conversion factor of α CO = 0.8 M / [K km s -1 pc 2 ]. Ratios of molecular gas masses derived from [CI] 1-0 and CO agree within the measurement uncertainties for five galaxies, and agree to better than a factor of two for another two with [CI] 1-0 measurements, after carefully taking CO excitation into account. This does not support the idea that intense, high-redshift starburst galaxies host large quantities of "CO-dark" gas. These results support the common assumptions underlying most molecular gas mass estimates made for massive, dusty, high-redshift starburst galaxies, although the good agreement between the masses obtained with both tracers cannot be taken as independent confirmation of either α CO or X CI

Radio and Infrared Selected Optically Invisible Sources in the Boötes NDWFS

We have combined data from the NOAO Deep Wide-Field Survey in Bo¨otes and the Spitzer Space Telescope to determine basic properties for sixteen optically “invisible” MIPS 24 µm (OIMS) and thirty-five optically “invisible” radio (OIRS) sources, including their spectral energy distributions (SED) and luminosities. Most OIMSs possess steep power-law SEDs over λrest = 1 − 10 µm, indicating the presence of obscured AGN in agreement with Spitzer spectroscopy. These objects are extremely luminous at rest-frame near and mid-IR (νLν(5 µm) ≈ 1038 − 1039 W), consistent with accretion near the Eddington limit and further implying that they host buried QSOs. The majority of the IRAC detected OIRSs have flat 3.6 to 24 µm SEDs, implying comparable emission from stellar photospheres and hot AGN illuminated dust. This may reflect relatively small amounts of dust close to the central engine or current low mass accretion rates. A small subset of OIRSs appear to be starburst dominated with photometric redshifts from 1.0 to 4.5. The OIMSs and OIRSs with significant starburst components have similar LK and stellar masses (M∗ ≈ 1011 M⊙) assuming minimal AGN contribution. Roughly half of the OIRSs are not detected by Spitzer’s IRAC or MIPS. These are most likely z & 2 radio galaxies. The IRAC detected OIRSs are more likely than OIMSs to appear non point-like in the 3.6 µm and 4.5 µm images, suggesting that interactions play a role in triggering their activity. The AGN powered OIMSs may represent sub-millimeter galaxies making the transition from starburst to accretion dominance in their evolution to current epoch massive ellipticals

The Cosmic Far-Infrared Background Buildup Since Redshift 2 at 70 and 160 microns in the COSMOS and GOODS fields

The Cosmic Far-Infrared Background (CIB) at wavelengths around 160 {\mu}m corresponds to the peak intensity of the whole Extragalactic Background Light, which is being measured with increasing accuracy. However, the build up of the CIB emission as a function of redshift, is still not well known. Our goal is to measure the CIB history at 70 {\mu}m and 160 {\mu}m at different redshifts, and provide constraints for infrared galaxy evolution models. We use complete deep Spitzer 24 {\mu}m catalogs down to about 80 {\mu}Jy, with spectroscopic and photometric redshifts identifications, from the GOODS and COSMOS deep infrared surveys covering 2 square degrees total. After cleaning the Spitzer/MIPS 70 {\mu}m and 160 {\mu}m maps from detected sources, we stacked the far-IR images at the positions of the 24 {\mu}m sources in different redshift bins. We measured the contribution of each stacked source to the total 70 and 160 {\mu}m light, and compare with model predictions and recent far-IR measurements made with Herschel/PACS on smaller fields. We have detected components of the 70 and 160 {\mu}m backgrounds in different redshift bins up to z ~ 2. The contribution to the CIB is maximum at 0.3 <= z <= 0.9 at 160{\mu}m (and z <= 0.5 at 70 {\mu}m). A total of 81% (74%) of the 70 (160) {\mu}m background was emitted at z < 1. We estimate that the AGN relative contribution to the far-IR CIB is less than about 10% at z < 1.5. We provide a comprehensive view of the CIB buildup at 24, 70, 100, 160 {\mu}m. IR galaxy models predicting a major contribution to the CIB at z < 1 are in agreement with our measurements, while our results discard other models that predict a peak of the background at higher redshifts. Our results are available online http://www.ias.u-psud.fr/irgalaxies/ .Comment: Accepted in Astronomy & Astrophysic

Interferometric 890 mu m images of high-redshift submillimeter galaxies

We present high-resolution 890 μm images of two 20 mJy submillimeter galaxies, SMM J123711+622212 and MIPS J142824.0+352619, obtained using the Submillimeter Array (SMA). Using submillimeter interferometric observations with an angular resolution of 25, the coordinates of these high-redshift sources are determined with an accuracy of 02. The new SMA data on SMM J123711+622212 reveal an unresolved submillimeter source offset to the east by 08 from an optical galaxy found in deep HST images, suggesting either a large galaxy with a dusty central region or an interacting galaxy system. The SMA image of hyperluminous (LFIR = 3.2 × 1013 L) source MIPS J142824.0+352619 provides a firm upper limit to the source size of 12. This constraint provides evidence that the foreground lens is only weakly affecting the observed high far-infrared luminosity

Imagerie ultrasonore quantitative haute fréquence : application au suivi de la formation du système cardiaque au stade embryonnaire chez la souris

La souris est notamment utilisée pour la compréhension de l(expression de l\u27ensemble des gènes du vivant. L\u27imagerie ultrasonore est l\u27une des modalités d\u27imagerie permettant un suivi in vivo et non invasif de son développement au cours du temps. Toutefois, la souris impose des contraintes de résolution spatiale et temporelle. Par l\u27utilisation de fréquences ultrasonores plus élevées, que celles utilisées chez l\u27homme, le développement du système cardiovasculaire et la rétrodiffusion du sang à très haute fréquence chez l\u27embryon de souris ont été étudiés in vivo. Entre 7 et 15 MHz, l\u27évolution de paramètres hémodynamiques, comme la fréquence cardiaque, a été quantifiée. Une quantification 3D a également été réalisée par la segmentation d\u27un volume ultrasonore. A 40 MHz, l\u27échogénicité du sang dans les chambres cardiaques de l\u27embryon variait entre EDs 12.5 et 17.5. Une diminution de 13 dB, liée aux changements morphologiques des globules rouges, a été mesurée entre ED 13.5 et ED 17.5

Les énergies marines renouvelables répondent-elles au modèle d’économie de la fonctionnalité ?

This article seeks to estimate the relevance of the service economy applied to marine renewable energy projects. This study is based on stakeholder contributions in public debate in Saint-Brieuc offshore wind farm project (France). We seek to analyze stakeholder perspectives through an application of a textual analysis on contributions (cahiers d’acteurs). Textual analysis reveals two main results, the first one turns to social and economic question with the impact on the territory, in particularly the employment and the training. The second issue concerns the energy efficiency of marine renewable technologies. For each of these issues, the discussion try to give a perspective regard to service economy theory and discuss about the relevance of service economy application in marine renewable energy sector.Cet article examine l’apport de l’économie de la fonctionnalité appliqué au cas des projets d’énergies marines renouvelables. L’étude repose sur les contributions des acteurs au débat public prenant part au projet d’éolien en mer en baie de Saint-Brieuc (France). Nous analysons la perception des acteurs face à l’implantation d’un parc éolien en mer par l’analyse textuelle des contributions versées dans les cahiers d’acteurs. L’analyse des données textuelles soulève deux problématiques, la première aborde les impacts socio-économiques pour le territoire (emploi et formation). La seconde concerne l’efficacité énergétique des énergies marines renouvelables

A neo-institutionalist approach to fisheries management systems in Europe and North America

This article focuses on the advantages and limitations of regionalization in fisheries, using the experiences of Europe, the United States, and Canada. Regionalization in European fisheries has encountered several obstacles that have greatly reduced its scope since implemented in 2004. After discussing the historical dimension of the Common Fisheries Policy, the methodological approach draws on neo-institutional economics and research on the socio-systems. The third section is devoted to a comparative approach between three main fisheries management systems in Europe, the United-States and Canada. Since the passage of the Magnuson Act, the U.S. has experimented with advanced forms of decentralization. Canada, on the other hand, has evolved towards a more centralized form of fisheries management. In reviewing these three cases, Europe seems to be somewhere between these other two examples. Decentralized management using markets and rights-based management in principle offers a better allocation of fishing efforts than centralized management because it takes into account the regional or even local nature of the resources exploited and the human populations that depend on them. However, the financial burden related to decentralized fisheries management may be expensive for the institutions involved. The comparative approach of the three major fisheries management systems is based on institutions guided by the search for a compromise between ecological and socio-economic criteria. Indeed, fisheries management in Europe and North American is now integrated into an ecosystems approach.L’article retient comme problématique la portée et les limites de la régionalisation des pêches, en s’appuyant sur les expériences en Europe, aux États-Unis et au Canada. Après un rappel de la dimension historique de la politique commune de la pêche en Europe, l’article offre une synthèse des principaux concepts tirés de l’économie néo-institutionnaliste et des travaux sur les systèmes socioécologiques. Une approche comparée en Europe, au Canada et aux États-Unis offre une diversité du caractère opérationnel des régimes de gestion des pêcheries. L’examen comparatif des trois grands systèmes de gestion des pêches est fondé sur des institutions guidées par la recherche d’un compromis entre critères écologiques et socio-économiques. La situation européenne se situe entre le mode décentralisé aux États-Unis et le régime canadien, le plus enraciné historiquement dans une conduite centralisée. En effet, la gestion des pêcheries, en Europe et en Amérique du Nord, est désormais intégrée à une approche écosystémique

Percolative behaviour and demagnetizing effects in disordered heterostructures

International audienceThis study provides a behavioural analysis of the particular demagnetizing effects displayed by disordered heterostructures close to a particular value (C p) of their magnetic load C: The emphasis is put on the convergence of evidences, got from several independent ways (experimental, analytical and numerical), of a percolative phenomenon in random distributions of magnetic particles that rules the sharp variations of the inner and outer demagnetizing effects at concentrations close to C p : When CoC p ; magnetic gaps, which originate from the magnetic dilution, may cause a cutoff of the magnetic flux paths in the composite medium, leading to inner demagnetizing effects only. When C > C p ; the delocalization of the magnetic poles leads the outer demagnetizing factor of the sample to switch from zero to its maximum value. The analytical approach of this phenomenon is based on an effective medium theory. It leads to a description of the interactions between magnetic inclusions that show a deep similarity with the main notions the reciprocity principle calls for.