An excess of star-forming galaxies in the fields of high-redshift QSOs

We present submillimetre (submm) and mid-infrared (MIR) imaging observations of five fields centred on quasi-stellar objects (QSOs) at 1.7 <z< 2.8. All five QSOs were detected previously at submm wavelengths. At 850 (450) μm, we detect 17 (11) submillimetre galaxies (SMGs) in addition to the QSOs. The total area mapped at 850 μm is ∼28 arcmin2 down to rms noise levels of 1–2 mJy beam−1, depending on the field. Integral number counts are computed from the 850-μm data using the same analytical techniques adopted by ‘blank-field’ submm surveys. We find that the ‘QSO-field’ counts show a clear excess over the blank-field counts at deboosted flux densities of ∼2–4 mJy; at higher flux densities, the counts are consistent with the blank-field counts. Robust MIR counterparts are identified for all four submm detected QSOs and ∼60 per cent of the SMGs. The MIR colours of the QSOs are similar to those of the local ultraluminous infrared galaxy (ULIRG)/active galactic nuclei (AGN) Mrk 231 if placed at 1 <z< 3 whilst most of the SMGs have colours very similar to those of the local ULIRG Arp 220 at 1 <z< 3. MIR diagnostics therefore find no strong evidence that the SMGs host buried AGN although we cannot rule out such a possibility. Taken together our results suggest that the QSOs sit in regions of the early universe which are undergoing an enhanced level of major star formation activity, and should evolve to become similarly dense regions containing massive galaxies at the present epoch. Finally, we find evidence that the level of star formation activity in individual galaxies appears to be lower around the QSOs than it is around more powerful radio-loud AGN at higher redshifts.We thank Ian Smail for extensive comments on the draft manuscript and Mark Thompson for useful discussions. The JCMT is operated by The Joint Astronomy Centre on behalf of the Science and Technology Facilities Council of the United Kingdom, the Netherlands Organisation for Scientific Research and the National Research Council of Canada. JCMT data were taken under project IDs M03AU46, M03BU32 and M04BU14. This work is based (in part) on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. JAS, MJP and FJC acknowledge support from the Royal Society. FJC acknowledges further support from the Spanish Ministerio de Educación y Ciencia under project ESP2006-13608

Viaducto de ferrocarril, en Gerona

This article describes the construction of the 5 km long viaduct, with 20 m corbels, intended to facilitate the expansion towards the north-eastern part of the city, the stretch of which was interrupted upto now by the railway line Barcelona-Port Bou. In view of the special conditions of the work and the need to maintain the traffic during the entire construction time the system of two self supporting arch centerings was chosen. Transversally the dintel is of trapezoidal cross-section with overhangs and lightened internally with circular holes. Longitudinally a solution of a continuous beam was adopted. Thus whether joints nor anchorages were required. The foundation rests directly on footings. The construction has been carried out in prestressed concrete and can be divided into three basic parts: entry on the Barcelona side; passenger station; passenger station-río Ter.Se describe la construcción de un viaducto de unos 5 km de vía elevada, con vanos de 20 m de luz media, destinado a facilitar la expansión hacia el NE. de la ciudad, cortada hasta ahora por la línea del ferrocarril Barcelona-Port Bou. Dadas las condiciones particulares de la obra y el imperativo de mantener el tráfico en todo momento, se eligió el sistema de dos cimbras autoportantes. Transversalmente el dintel se resuelve a base de sección trapecial con voladizos, aligerado interiormente con alvéolos circulares. Longitudinalmente se adoptó la solución de viga continua, por las ventajas que representa en cuanto a supresión de juntas y de anclajes. Cimentación sobre zapatas directas. La construcción se ha realizado con hormigón pretensado y puede dividirse en tres partes fundamentales: Acceso lado Barcelona; Estación de viajeros; Estación de viajeros-río Ter

A crystalline and free-standing silver thiocarboxylate thin-film showing high green to yellow luminescence

The simple direct synthesis of Cu(ii) and Ag(i) salts and thiobenzoic acid under ambient conditions allows the preparation of two bidimensional coordination polymers [M(TB)]n (TB = thiobenzoate; M = Cu (1) or Ag (2)). Their electrical and luminescent properties show that these are multifunctional materials. Interestingly 1 and 2 undergo a reversible solubilization process. This unusual feature and their simple preparation allow us to prepare a crystalline and free-standing thin-film of 2, using an interfacial procedure, which shows a remarkable thermochromic luminescence.This work was supported by MICINN (MAT2013-46753-C2-1-P and CTQ2013-48635-C2-1-P) and Generalitat Valenciana (projects PrometeoII/2014/076 and ISIC

Systematic study of the impact of MOF densification into tablets on textural and mechanical properties

Four different metal-organic framework powders (UiO-66, UiO-66-NH, UiO-67, and HKUST-1) were shaped into tablets. The effect of the applied pressure on porous properties, mechanical resistance and tablet bulk density is reported. We observe a linear relationship between densification and tensile strength for all four studied MOFs, with the slope being MOF-dependent. We also report conditions for improving significantly the volumetric uptake. Finally, we evaluated our tablets' stability over time in the presence of moisture

Performance of a small size telescope (SST-1M) camera for gamma-ray astronomy with the Cherenkov Telescope Array

The foreseen implementations of the Small Size Telescopes (SST) in CTA will provide unique insights into the highest energy gamma rays offering fundamental means to discover and under- stand the sources populating the Galaxy and our local neighborhood. Aiming at such a goal, the SST-1M is one of the three different implementations that are being prototyped and tested for CTA. SST-1M is a Davies-Cotton single mirror telescope equipped with a unique camera technology based on SiPMs with demonstrated advantages over classical photomultipliers in terms of duty-cycle. In this contribution, we describe the telescope components, the camera, and the trigger and readout system. The results of the commissioning of the camera using a dedicated test setup are then presented. The performances of the camera first prototype in terms of expected trigger rates and trigger efficiencies for different night-sky background conditions are presented, and the camera response is compared to end-to-end simulations.Comment: All CTA contributions at arXiv:1709.0348

The host galaxies of luminous type 2 AGNs at z ∼ 0.3–0.4

ABSTRACT: We study the morphological and structural properties of the host galaxies associated with 57 optically selected luminous type 2 active galactic nuclei (AGNs) at z ∼ 0.3–0.4: 16 high-luminosity Seyfert 2 [HLSy2, 8.0 ≤ log(L[oIII]/Lʘ) < 8.3] and 41 obscured [QSO2, log(L[O III]/Lʘ) ≥ 8.3] quasars. With this work, the total number of QSO2s at z < 1 with parametrized galaxies increases from ∼35 to 76. Our analysis is based on Hubble Space Telescope WFPC2 and ACS images that we fit with GALFIT. HLSy2s and QSO2s show a wide diversity of galaxy hosts. The main difference lies in the higher incidence of highly disturbed systems among QSO2s. This is consistent with a scenario in which galaxy interactions are the dominant mechanism triggering nuclear activity at the highest AGN power. There is a strong dependence of galaxy properties with AGN power (assuming L[O III] is an adequate proxy). The relative contribution of the spheroidal component to the total galaxy light (B/T) increases with L[O III]. While systems dominated by the spheroidal component spread across the total range of L[O III], most disc-dominated galaxies concentrate at log(L[O III]/Lʘ)JUM and MVM acknowledge support from the Spanish former Ministerio de Economía y Competitividad through the grants AYA2012-32295 and AYA2015-64346-C2-2-P. FB also acknowledges support from grant AYA2016-77237-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO). JPL acknowledges support from the Spanish Ministerio de Economía y Competitividad through the grant AYA2017-85170-R. BRP acknowledges financial support from the Spanish Ministry of Economy and Competitiveness through grant ESP2015-68964. F.J.C. acknowledges financial support through grant AYA2015-64346-C2-1-P (MINECO/FEDER)

Development of a strategy for calibrating the novel SiPM camera of the SST-1M telescope proposed for the Cherenkov Telescope Array

CTA will comprise a sub-array of up to 70 small size telescopes (SSTs) at the southern array. The SST-1M project, a 4 m-diameter Davies Cotton telescope with 9 degrees FoV and a 1296 pixels SiPM camera, is designed to meet the requirements of the next generation ground based gamma-ray observatory CTA in the energy range above 3 TeV. Silicon photomultipliers (SiPM) cameras of gamma-ray telescopes can achieve good performance even during high night sky background conditions. Defining a fully automated calibration strategy of SiPM cameras is of great importance for large scale production validation and online calibration. The SST-1M sub-consortium developed a software compatible with CTA pipeline software (CTApipe). The calibration of the SST-1M camera is based on the Camera Test Setup (CTS), a set of LED boards mounted in front of the camera. The CTS LEDs are operated in pulsed or continuous mode to emulate signal and night sky background respectively. Continuous and pulsed light data analysis allows us to extract single pixel calibration parameters to be used during CTA operation.Comment: All CTA contributions at arXiv:1709.0348

Control Software for the SST-1M Small-Size Telescope prototype for the Cherenkov Telescope Array

The SST-1M is a 4-m Davies--Cotton atmospheric Cherenkov telescope optimized to provide gamma-ray sensitivity above a few TeV. The SST-1M is proposed as part of the Small-Size Telescope array for the Cherenkov Telescope Array (CTA), the first prototype has already been deployed. The SST-1M control software of all subsystems (active mirror control, drive system, safety system, photo-detection plane, DigiCam, CCD cameras) and the whole telescope itself (master controller) uses the standard software design proposed for all CTA telescopes based on the ALMA Common Software (ACS) developed to control the Atacama Large Millimeter Array (ALMA). Each subsystem is represented by a separate ACS component, which handles the communication to and the operation of the subsystem. Interfacing with the actual hardware is performed via the OPC UA communication protocol, supported either natively by dedicated industrial standard servers (PLCs) or separate service applications developed to wrap lower level protocols (e.g. CAN bus, camera slow control) into OPC UA. Early operations of the telescope without the camera were already carried out. The camera is fully assembled and is capable to perform data acquisition using artificial light source.Comment: In Proceedings of the 35th International Cosmic Ray Conference (ICRC2017), Busan, Korea. All CTA contributions at arXiv:1709.0348

Reversible transformation between Cu(i)-thiophenolate coordination polymers displaying luminescence and electrical properties

A one-dimensional [Cu6I3(TP)3(MeCN)2]n (1) coordination polymer (CP) has been prepared by the direct reaction between CuI and a thiophenol (TP) ligand. The reversible conversion reaction between 1 and the homoleptic 1D-CP [Cu(TP)]n (2) is observed in acetonitrile upon controlling the CuI ratio. Interestingly, CPs 1 and 2 are multifunctional materials showing both luminescence and electrical properties. Photoluminescence measurements reveal that 1 and 2 are emissive in the blue and the red regions, respectively. Additionally, both materials show electrical conductivity at room temperature (1.2 × 10-8 for 1 and 3.7 × 10-4 S cm-1 for 2) indicating a semiconductor behaviour. DFT calculations have been used to rationalise these observationsThis work was supported in part by MICINN (grant MAT2016-77608-C3-1-P