45 research outputs found

    Characterisation of Herschel-selected strong lens candidates through HST and sub-mm/mm observations

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    We have carried out HST snapshot observations at 1.1 ÎŒ\mum of 281 candidate strongly lensed galaxies identified in the wide-area extragalactic surveys conducted with the Herschel space observatory. Our candidates comprise systems with flux densities at 500 Ό500\,\mumS500≄80 S_{500}\geq 80 mJy. We model and subtract the surface brightness distribution for 130 systems, where we identify a candidate for the foreground lens candidate. After combining visual inspection, archival high-resolution observations, and lens subtraction, we divide the systems into different classes according to their lensing likelihood. We confirm 65 systems to be lensed. Of these, 30 are new discoveries. We successfully perform lens modelling and source reconstruction on 23 systems, where the foreground lenses are isolated galaxies and the background sources are detected in the HST images. All the systems are successfully modelled as a singular isothermal ellipsoid. The Einstein radii of the lenses and the magnifications of the background sources are consistent with previous studies. However, the background source circularised radii (between 0.34 kpc and 1.30 kpc) are ∌\sim3 times smaller than the ones measured in the sub-mm/mm for a similarly selected and partially overlapping sample. We compare our lenses with those in the SLACS survey, confirming that our lens-independent selection is more effective at picking up fainter and diffuse galaxies and group lenses. This sample represents the first step towards characterising the near-IR properties and stellar masses of the gravitationally lensed dusty star-forming galaxies.Comment: 57 pages, 18 figures, 11 tables. Accepted for publication in MNRA

    Euclid Near Infrared Spectrometer and Photometer instrument concept and first test results obtained for different breadboards models at the end of phase C

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    The Euclid mission objective is to understand why the expansion of the Universe is accelerating through by mapping the geometry of the dark Universe by investigating the distance-redshift relationship and tracing the evolution of cosmic structures. The Euclid project is part of ESA's Cosmic Vision program with its launch planned for 2020 (ref [1]). The NISP (Near Infrared Spectrometer and Photometer) is one of the two Euclid instruments and is operating in the near-IR spectral region (900- 2000nm) as a photometer and spectrometer. The instrument is composed of: - a cold (135K) optomechanical subsystem consisting of a Silicon carbide structure, an optical assembly (corrector and camera lens), a filter wheel mechanism, a grism wheel mechanism, a calibration unit and a thermal control system - a detection subsystem based on a mosaic of 16 HAWAII2RG cooled to 95K with their front-end readout electronic cooled to 140K, integrated on a mechanical focal plane structure made with molybdenum and aluminum. The detection subsystem is mounted on the optomechanical subsystem structure - a warm electronic subsystem (280K) composed of a data processing / detector control unit and of an instrument control unit that interfaces with the spacecraft via a 1553 bus for command and control and via Spacewire links for science data This presentation describes the architecture of the instrument at the end of the phase C (Detailed Design Review), the expected performance, the technological key challenges and preliminary test results obtained for different NISP subsystem breadboards and for the NISP Structural and Thermal model (STM)

    Global Boundary Stratotype Section and Point (GSSP) for the Anthropocene Series: Where and how to look for potential candidates

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    Data products of the surface brightness modelling of the confirmed and candidates lenses in Borsato et al. 2023.

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    <p>This repository contains the data products for the surface brightness analysis of strongly lensed candidates presented in Borsato et al. 2023. This repository is organized as follows.</p><p>The folder `cutouts' contains the cutouts (20x20 arcsec) of all the HST snapshots.</p><p>The folder `SB_models' includes the A and B folders containing the confirmed lenses and candidate lenses (A and B classes in the paper). Each of these folders contains a set of subfolders including the image cutouts, surface brightness models, residuals, noise maps, and PSFs of the confirmed lenses. </p&gt

    A modular optically powered floating high voltage generator

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    The feasibility of fully floating high voltage (HV) generation was demonstrated producing a prototype of a modular HV system. The primary power source is provided by a high efficiency semiconductor power cell illuminated by a laser system ensuring the floating nature of each module. The HV is then generated by dc-dc conversion and a HV multiplier. The possibility of series connection among modules was verified. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790420

    AVM unpacking procedure at INFN Padova

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    The aim of the NIOMADA AVM is to provide the ICU with an electrical simulator and the NI-DPU with a SCE. The NIOMAD AVM will carry out a Short and a Full Functional test at room temperature before its delivery to TAS-I

    Aragonite-Calcite Relationships in Speleothems (Grotte De Clamouse, France): Environment, Fabrics, and Carbonate Geochemistry

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    In Grotte de Clamouse (France), aragonite forms in a variety of crystal habits whose properties reflect the conditions of formation. Prolonged degassing and evaporation yield needle aragonite, which is more enriched in 18O and 13C than aragonite ray crystals, which form near isotopic equilibrium. At present, aragonite ray crystals form at the tops of stalagmites at very low discharge (0.00035 ml/ min), and when fluid Mg/Ca ratio is \u3e 1.1. Temperature and evaporation do not seem to have a significant role in their formation. The presence of aragonite in stalagmites should be indicative of a decrease in drip rate related to either dry climate conditions or local hydrology. Fossil aragonite was in part replaced by calcite in a time frame \u3c 1.0 ka, possibly through the combined effects of dissolution of aragonite, and precipitation of calcite, which preferentially nucleated on calcite cements that had previously formed between aragonite rays. Commonly, the replacement phase inherited the textural and chemical characteristics of the precursor aragonite prisms and needles (and in particular the ÎŽ13C signal and U content), and preserved aragonite relicts (up to 16 weight %). The isotope signal of different aragonite habits may reflect conditions of formation rather than climate parameters. The real extent of aragonite-to-calcite transformation may be underestimated when replacement calcite inherits both textural and chemical properties of the precursor

    Two DPUs synchronization test

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    The two DPUs synchronization test procedure is explained and the results are presente

    ICU FM Electrical Integration Test Procedure: AS RUN

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    The purpose of this document is to describe the electrical and ASW integration procedure of ICU FM. The procedure is applicable to the ICU FM integration in preparation to the NISP FM TV test 1 and 2. The integration will use the NISP SCOE as S/C simulator. The document describes the ICU PFM electrical integration “As Ru
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