29 research outputs found
A near/mid infrared search for ultra-bright submillimetre galaxies: searching for sosmic eyelash analogues
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
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
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
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
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
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
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
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
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+