29 research outputs found

    A near/mid infrared search for ultra-bright submillimetre galaxies: searching for sosmic eyelash analogues

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    We present results from a near/mid IR search for submillimetre galaxies over a region of 6230 sq deg. of the southern sky. We used a cross-correlation of the VISTA Hemispheric Survey (VHS) and the WISE database to identify bright galaxies (Ks � 18.2) with near/mid IR colours similar to those of the high redshift lensed sub-mm galaxy SMM J2135-0102. We find 7 galaxies which fulfill all five adopted near/mid IR colour (NMIRQC) criteria and resemble the SED of the reference galaxy at these wavelengths. For these galaxies, which are broadly distributed in the sky, we deter- mined photometric redshifts in the range z=1.6-3.2. We searched the VHS for clusters of galaxies, which may be acting as gravitational lenses, and found that 6 out of the 7 galaxies are located within 3.5 arcmin of a cluster/group of galaxies. Using the J-Ks vs J sequences we determine photometric redshifts for these clusters/groups in the range z=0.2-0.9. We propose the newly identified sources are ultra-bright high red- shift lensed SMG candidates. Follow-up observations in the sub-mm and mm are key to determine the ultimate nature of these objects

    Discovery of a lensed ultrabright submillimeter galaxy at z = 2.0439. Póster

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    We report an ultra-bright lensed submillimeter galaxy (SMG) at z = 2.0439, WISE J132934.18+224327.3, identified as a result of a full-sky cross-correlation of the AllWISE and Planck compact source catalogs aimed to search for bright analogs of the submillimeter galaxy SMMJ2135, the Cosmic Eyelash. Inspection of archival SCUBA-2 observations of the candidates revealed a source with fluxes (S850μm= 130 mJy) consistent with the Planck measurements. The centroid of the SCUBA-2 source coincides within 1 arcsec with the position of the AllWISE mid-IR source, and, remarkably, with an arc shaped lensed galaxy in HST images at visible wavelengths. Low-resolution rest-frame UV-optical spectroscopy of this lensed galaxy obtained with 10.4 m GTC reveals the typical absorption lines of a starburst galaxy. Gemini-N near-IR spectroscopy provided a clear detection of H_ emission. The lensed source appears to be gravitationally magnified by a massive foreground galaxy cluster lens at z = 0.44, modeling with Lenstool indicates a lensing amplification factor of 11±2. We determine an intrinsic rest-frame 8-1000-μm luminosity, LIR, of (1.3±0.1)×1013 L⊙, and a likely star-formation rate (SFR) of _ 500−2000 M⊙yr−1 . The SED shows a remarkable similarity with the Cosmic Eyelash from optical-mid/IR to sub-millimeter/radio, albeit at higher fluxes

    Dielectric susceptibility of the Coulomb-glass

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    We derive a microscopic expression for the dielectric susceptibility X of a Coulomb glass, which corresponds to the definition used in classical electrodynamics, the derivative of the polarization with respect to the electric field. The fluctuation–dissipation theorem tells us that is a function of the thermal fluctuations of the dipole moment of the system. We calculate X numerically for three–dimensional Coulomb glasses as a function of temperature and frequency.We acknowledge financial support from the DGES project number PB96-1118, SMWK, and DFG (SFB 393). A great part of this work was performed during A. D.-S.’s visit at the IFW Dresden; A. D.-S. thanks the IFW for its hospitality

    FastCam: Un instrumento de alta resolución espacial para astronomía

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    FastCam es un instrumento de alta resolución espacial desarrollado por la Universidad Politécnica de Cartagena y por el Instituto de Astrofísica de Canarias (IAC). Este instrumento está diseñado para corregir los efectos no deseados que las turbulencias atmosféricas producen en las imágenes astronómicas. FastCam ha sido probada con exito en telescopios terrestres de 2 a 4 metros de apertura obteniendo imágenes comparables a las obtenidas por el telescopio espacial Hubble.Fundación Séneca. Plan de Ciencia y Tecnología de la Región de Murcia. Código: 08801/PI/0

    High-resolution optical imaging of the core of the globular cluster M15 with FastCam

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    We present high-resolution I-band imaging of the core of the globular cluster M15 obtained at the 2.5 m Nordic Optical Telescope with FastCam, a low readout noise L3CCD based instrument. Short exposure times (30 ms) were used to record 200000 images (512 x 512 pixels each) over a period of 2 hours 43 min. The lucky imaging technique was then applied to generate a final image of the cluster centre with FWHM ~ 0".1 and 13" x 13" FoV. We obtained a catalogue of objects in this region with a limiting magnitude of I=19.5. I-band photometry and astrometry are reported for 1181 stars. This is the deepest I-band observation of the M15 core at this spatial resolution. Simulations show that crowding is limiting the completeness of the catalogue. At shorter wavelengths, a similar number of objects has been reported using HST/WFPC observations of the same field. The cross-match with the available HST catalogues allowed us to produce colour-magnitude diagrams where we identify new Blue Straggler star candidates and previously known stars of this class.Comment: 11 pages, 15 figures. Accepted for publication in Monthly Notices of the Royal Astronomical Societ

    AOLI-- Adaptive Optics Lucky Imager: Diffraction Limited Imaging in the Visible on Large Ground-Based Telescopes

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    The highest resolution images ever taken in the visible were obtained by combining Lucky Imaging and low order adaptive optics. This paper describes a new instrument to be deployed on the WHT 4.2m and GTC 10.4 m telescopes on La Palma, with particular emphasis on the optical design and the expected system performance. A new design of low order wavefront sensor using photon counting CCD detectors and multi-plane curvature wavefront sensor will allow dramatically fainter reference stars to be used, allowing virtually full sky coverage with a natural guide star. This paper also describes a significant improvements in the efficiency of Lucky Imaging, important advances in wavefront reconstruction with curvature sensors and the results of simulations and sensitivity limits. With a 2 x 2 array of 1024 x 1024 photon counting EMCCDs, AOLI is likely to be the first of the new class of high sensitivity, near diffraction limited imaging systems giving higher resolution in the visible from the ground than hitherto been possible from space.Comment: SPIE vol 8446, 201

    The AOLI low-order non-linear curvature wavefront sensor: a method for high sensitivity wavefront reconstruction

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    The Adaptive Optics Lucky Imager (AOLI) is a new instrument under development to demonstrate near diffraction limited imaging in the visible on large ground-based telescopes. We present the adaptive optics system being designed for the instrument comprising a large stroke deformable mirror, fixed component non-linear curvature wavefront sensor and photon-counting EMCCD detectors. We describe the optical design of the wavefront sensor where two photoncounting CCDs provide a total of four reference images. Simulations of the optical characteristics of the system are discussed, with their relevance to low and high order AO systems. The development and optimisation of high-speed wavefront reconstruction algorithms are presented. Finally we discuss the results of simulations to demonstrate the sensitivity of the system.Comment: 10 pages. To be published in Proc SPIE 8447: Adaptive Optics Systems II

    A low mass cluster of extremely red galaxies at z=1.10 in the GOODS Southern Field

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    We have studied the spatial clustering of high redshift (z > 1) extremely red objects (EROs) as a function of photometric redshift in the GOODS Southern Field using public data. A remarkable overdensity of extremely red galaxies (I-Ks > 4) is found at an average photometric redshift z=1.10. Nine objects (six are EROs) within 50 arcsec of the brightest infrared galaxy in this overdensity present spectroscopic redshifts in the range 1.094 < z < 1.101 with a line-of-sight velocity dispersion of 433 km/s typical of an Abell richness class R=0 cluster. Other potential members of this cluster, designated as GCL J0332.2-2752, have been identified using photometric redshifts and the galaxy density profile studied as a function of radius. The mass of the cluster is preliminary estimated at M ~ 5-7 x 10^{13} M_{\sun}. Using available Chandra data, we limit the rest-frame X-ray luminosity of the cluster to less than L_X = 7.3 x 10^{42} erg/s (0.5-2.0 keV). This low-mass, low L_X cluster at z > 1 shows the potential of EROs to trace clusters of galaxies at high redshift.Comment: Accepted for publication in MNRAS, 18 Feb 0

    Euclid: una misión espacial con participación de la UPCT

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    La Agencia Espacial Europea aprobó en octubre de 2011 la misión científica Euclid dentro del programa Cosmic Vision 2015-2025. El objetivo de esta misión es medir parámetros relativos a la energía y materia oscura del universo con una precisión sin precedentes. Para ello,el satélite Euclid estará equipado con un telescopiode 1.2 metros y dos instrumentos: El instrumento VIS(VisibleImager) y el instrumento NISP (Near-Infrared Spectrometer Photometer). La Universidad Politécnica de Cartagena junto con el Institutode Astrofísica de Canarias son responsables del diseño, construcción y validación de la electrónica de control del instrumento NISP.Plan Nacional de I+D+
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