1,030 research outputs found

    Resolving the molecular gas around the lensed quasar RXJ0911.4+0551

    Full text link
    We report on high angular resolution observations of the CO(7-6) line and millimeter continuum in the host galaxy of the gravitationally lensed (z~2.8) quasar RXJ0911.4+0551 using the Plateau de Bure Interferometer. Our CO observations resolve the molecular disk of the source. Using a lens model based on HST observations we fit source models to the observed visibilities. We estimate a molecular disk radius of 1±\pm0.2 kpc and an inclination of 69±\pm6\deg, the continuum is more compact and is only marginally resolved by our observations. The relatively low molecular gas mass, Mgas=(2.3±0.5)×109Mgas=(2.3\pm 0.5)\times 10^{9} Msolar, and far infrared luminosity, LFIR=(7.2±1.5)×1011LFIR=(7.2\pm 1.5) \times 10^{11} Lsolar, of this quasar could be explained by its relatively low dynamical mass, Mdyn=(3.9±0.9)×109Mdyn=(3.9\pm 0.9)\times 10^9 Msolar. It would be a scaled-down version the QSOs usually found at high-z. The FIR and CO luminosities lie on the correlation found for QSOs from low to high redshifts and the gas-to-dust ratio (45±1745\pm 17) is similar to the one measured in the z=6.4 QSO, SDSS J1148+5251. Differential magnification affects the continuum-to-line luminosity ratio, the line profile and possibly the spectral energy distribution.Comment: Accepted for publication in A&A, revised after language editin

    Zur Zukunft der kommunalen Wohnungspolitik in Deutschland und Europa. Tagungsband: Referate und Diskussionen im Rahmen des 3. Halleschen Kolloquiums zur Kommunalen Wirtschaft am 5. und 6. November 2009

    Full text link
    Am 5. und 6. November 2009 veranstaltete das IWH ein Kolloquium zu einem Themenschwerpunkt aus dem Bereich der Kommunalwirtschaft. Das zentrale Anliegen der Konferenz bestand darin, die künftige Rolle der kommunalen Wohnungswirtschaft zu diskutieren und im Vergleich zu alternativen wohnungspolitischen Instrumenten zu bewerten. Das Kolloquium befasste sich mit den Aufgaben und Aktivitäten, die den Kommunen auf dem Wohnungsmarkt zukommen bzw. unter modernen wirtschaftlichen und gesellschaftlichen Bedingungen zukommen sollten. Die Tagungsbeiträge sind in diesem Band veröffentlicht

    The ARGUS Vertex Trigger

    Get PDF
    A fast second level trigger has been developed for the ARGUS experiment which recognizes tracks originating from the interaction region. The processor compares the hits in the ARGUS Micro Vertex Drift Chamber to 245760 masks stored in random access memories. The masks which are fully defined in three dimensions are able to reject tracks originating in the wall of the narrow beampipe of 10.5\,mm radius.Comment: gzipped Postscript, 27 page

    Excitation of the molecular gas in the nuclear region of M82

    Get PDF
    We present high resolution HIFI spectroscopy of the nucleus of the archetypical starburst galaxy M82. Six 12CO lines, 2 13CO lines and 4 fine-structure lines are detected. Besides showing the effects of the overall velocity structure of the nuclear region, the line profiles also indicate the presence of multiple components with different optical depths, temperatures and densities in the observing beam. The data have been interpreted using a grid of PDR models. It is found that the majority of the molecular gas is in low density (n=10^3.5 cm^-3) clouds, with column densities of N_H=10^21.5 cm^-2 and a relatively low UV radiation field (GO = 10^2). The remaining gas is predominantly found in clouds with higher densities (n=10^5 cm^-3) and radiation fields (GO = 10^2.75), but somewhat lower column densities (N_H=10^21.2 cm^-2). The highest J CO lines are dominated by a small (1% relative surface filling) component, with an even higher density (n=10^6 cm^-3) and UV field (GO = 10^3.25). These results show the strength of multi-component modeling for the interpretation of the integrated properties of galaxies.Comment: Accepted for publication in A&A Letter

    A spinorial energy functional: critical points and gradient flow

    Full text link
    On the universal bundle of unit spinors we study a natural energy functional whose critical points, if dim M \geq 3, are precisely the pairs (g, {\phi}) consisting of a Ricci-flat Riemannian metric g together with a parallel g-spinor {\phi}. We investigate the basic properties of this functional and study its negative gradient flow, the so-called spinor flow. In particular, we prove short-time existence and uniqueness for this flow.Comment: Small changes, final versio

    Pulse processing routines for neutron time-of-flight data

    Full text link
    A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.Comment: 13 pages, 10 figures, 5 table

    Enhanced [CII] emission in a z=4.76 submillimetre galaxy

    Get PDF
    We present the detection of bright [CII] emission in the z=4.76 submillimetre galaxy LESS J033229.4-275619 using the Atacama Pathfinder EXperiment. This represents the highest redshift [CII] detection in a submm selected, star-formation dominated system. The AGN contributions to the [CII] and far-infrared (FIR) luminosities are small. We find an atomic mass derived from [CII] comparable to the molecular mass derived from CO. The ratio of the [CII], CO and FIR luminosities imply a radiation field strength G_0~10^3 and a density ~10^4 cm^-3 in a kpc-scale starburst, as seen in local and high redshift starbursts. The high L_[CII]/L_FIR=2.4x10^-3 and the very high L_[CII]/L_CO(1-0) ~ 10^4 are reminiscent of low metallicity dwarf galaxies, suggesting that the highest redshift star-forming galaxies may also be characterised by lower metallicities. We discuss the implications of a reduced metallicity on studies of the gas reservoirs, and conclude that especially at very high redshift, [CII] may be a more powerful and reliable tracer of the interstellar matter than CO.Comment: 5 pages, 2 figures; accepted for publication in Astronomy & Astrophysics Letter
    corecore