The AGN Outflow in the HDFS Target QSO J2233-606 from a High-Resolution VLT/UVES Spectrum

We present a detailed analysis of the intrinsic UV absorption in the central HDFS target QSO J2233-606, based on a high-resolution, high S/N (~25 -- 50) spectrum obtained with VLT/UVES. This spectrum samples the cluster of intrinsic absorption systems outflowing from the AGN at radial velocities v ~ -5000 -- -3800 km/s in the key far-UV diagnostic lines - the lithium-like CNO doublets and H I Lyman series. We fit the absorption troughs using a global model of all detected lines to solve for the independent velocity-dependent covering factors of the continuum and emission-line sources and ionic column densities. This reveals increasing covering factors in components with greater outflow velocity. Narrow substructure is revealed in the optical depth profiles, suggesting the relatively broad absorption is comprised of a series of multiple components. We perform velocity-dependent photoionization modeling, which allows a full solution to the C, N, and O abundances, as well as the velocity resolved ionization parameter and total column density. The absorbers are found to have supersolar abundances, with [C/H] and [O/H] ~0.5 -- 0.9, and [N/H] ~ 1.1 -- 1.3, consistent with enhanced nitrogen production expected from secondary nucleosynthesis processes. Independent fits to each kinematic component give consistent results for the abundances. The lowest-ionization material in each of the strong absorbers is modeled with similar ionization parameters. Components of higher-ionization (indicated by stronger O VI relative to C IV and N V) are present at velocities just redward of each low-ionization absorber. We explore the implications of these results for the kinematic-geometric-ionization structure of the outflow.Comment: 12 pages, 10 figures, emulateapj, accepted for publication in Ap

Mobile target detection on SAR images

The synthesis of multiple look SAR images allows for speckle noise reduction through non-coherent summing . We present here a method for detection and localisation of moving targets derived from multiple look imaging . Its basis is to compute severa l single-look pushbroom images, then to search for pointwise reflections whose location and/or intensity vary from look to look . The approach is validated with several examples . Raw signals were acquired with the RAMSES airborne experimental radar o f the ONERA, during a MTI test-flight . Theoretical limitation studies show the strong Zink between the multi-look method and more conventional MTI technics such a s Doppler filtering (for radially moving targets) and time-frequency transforms (for detecting cross-range motions through thei r difference in Doppler frequency slope )La synthèse de plusieurs vues en imagerie SAR permet une diminution du bruit de speckle par sommation incohérente. Nous exposons dans ce document une méthode pour la détection des cibles mobiles fondée sur l'imagerie SAR multi-vues. Le principe est de calculer un ensemble de vues panoramiques pour des valeurs différentes du Doppler et de détecter par des techniques de traitement d'image classiques, des échos dont la position et/ou l'intensité varient d'une vue à l'autre. La méthode est illustrée par de nombreux exemples. Les signaux bruts ont été obtenus au cours d'une campagne de mesure de la station RAMSÈS réalisée à l'ONERA. L'étude des limitations théoriques montre que les méthodes de MTI plus classiques comme le filtrage Doppler (détection des cibles à vitesse radiale) ou les transformées temps-fréquence (détection des échos de pente Doppler atypique pour la mise en évidence de mouvements transversaux) ont un lien avec la méthode multi-vues proposée ici

What Determines the Depth of BALs? Keck HIRES Observations of BALQSO 1603+300

We find that the depth and shape of the broad absorption lines (BALs) in BALQSO 1603+3002 are determined largely by the fraction of the emitting source which is covered by the BAL flow. In addition, the observed depth of the BALs is poorly correlated with their real optical depth. The implication of this result is that abundance studies based on direct extraction of column densities from the depth of the absorption troughs are unreliable. Our conclusion is based on analysis of unblended absorption features of two lines from the same ion (in this case the Si IV doublet), which allows unambiguous separation of covering factor and optical depth effects. The complex morphology of the covering factor as a function of velocity suggests that the BALs are produced by several physically separated outflows. The covering factor is ion dependent in both depth and velocity width. We also find evidence that in BALQSO 1603+3002 the flow does not cover the broad emission line region.Comment: 13 pages, 2 figures, accepted for publication in Ap

Inherent thermometry in a hybrid superconducting tunnel junction

We discuss inherent thermometry in a Superconductor - Normal metal - Superconductor tunnel junction. In this configuration, the energy selectivity of single-particle tunneling can provide a significant electron cooling, depending on the bias voltage. The usual approach for measuring the electron temperature consists in using an additional pair of superconducting tunnel junctions as probes. In this paper, we discuss our experiment performed on a different design with no such thermometer. The quasi-equilibrium in the central metallic island is discussed in terms of a kinetic equation including injection and relaxation terms. We determine the electron temperature by comparing the micro-cooler experimental current-voltage characteristic with isothermal theoretical predictions. The limits of validity of this approach, due to the junctions asymmetry, the Andreev reflection or the presence of sub-gap states are discussed

A functional update of the Escherichia coli K-12 genome

Author Posting. © 2001 Serres et al. The definitive version was published in Genome Biology 2 (2001): research0035.1–0035.7, doi:10.1186/gb-2001-2-9-research0035.Background: Since the genome of Escherichia coli K-12 was initially annotated in 1997, additional functional information based on biological characterization and functions of sequence-similar proteins has become available. On the basis of this new information, an updated version of the annotated chromosome has been generated. Results: The E. coli K-12 chromosome is currently represented by 4,401 genes encoding 116 RNAs and 4,285 proteins. The boundaries of the genes identified in the GenBank Accession U00096 were used. Some protein-coding sequences are compound and encode multimodular proteins. The coding sequences (CDSs) are represented by modules (protein elements of at least 100 amino acids with biological activity and independent evolutionary history). There are 4,616 identified modules in the 4,285 proteins. Of these, 48.9% have been characterized, 29.5% have an imputed function, 2.1% have a phenotype and 19.5% have no function assignment. Only 7% of the modules appear unique to E. coli, and this number is expected to be reduced as more genome data becomes available. The imputed functions were assigned on the basis of manual evaluation of functions predicted by BLAST and DARWIN analyses and by the MAGPIE genome annotation system. Conclusions: Much knowledge has been gained about functions encoded by the E. coli K-12 genome since the 1997 annotation was published. The data presented here should be useful for analysis of E. coli gene products as well as gene products encoded by other genomes.This work was supported by NIH grant RO1 RR07861, the NASA Astrobiology Institute grant NCC2-1054, grants from the Edward Mallinckrodt, Jr Foundation and the Sinsheimer Foundation, and NSF grants NSF DBI - 9984882 and NSF IIS - 9996304