A5039057137- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- CCD and CMOS Imaging Sensors
- Astronomical Observations and Instrumentation
- Infrared Target Detection Methodologies
- Astrophysics and Star Formation Studies
- Calibration and Measurement Techniques
- Astro and Planetary Science
- Optical Systems and Laser Technology
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Advanced Sensor Technologies Research
- Astrophysical Phenomena and Observations
- Particle Accelerators and Free-Electron Lasers
- Advanced Measurement and Detection Methods
- Radiation Detection and Scintillator Technologies
- Astrophysics and Cosmic Phenomena
- Advanced Fiber Laser Technologies
- Solar and Space Plasma Dynamics
- Solid State Laser Technologies
- Medical Imaging Techniques and Applications
- Embedded Systems Design Techniques
- Semiconductor Lasers and Optical Devices
- Radiation Effects in Electronics
UK Astronomy Technology Centre
2020
University of Sheffield
2009-2019
Institute of Space Sciences
2018
Abcam (United States)
2017
European Southern Observatory
2017
Centro de Astrobiología
2016
Max Planck Institute for Astronomy
2014
Isaac Newton Group
2000-2010
Ascamm Technologic Center
2010
Instituto de Astrofísica de Canarias
2006
With orbital periods of the order tens minutes or less, AM Canum Venaticorum stars are ultracompact, hydrogen deficient binaries with shortest any binary subclass, and expected to be among strongest gravitational wave sources in sky. To date, only known eclipsing source this type is P = 28 min SDSS J0926+3624. We present multiband, high time resolution light curves system, collected WHT/ULTRACAM 2006 2009. supplement these data additional observations made LT/RISE, XMM_Newton Catalina...
We report a transit timing study of the transiting exoplanetary system HD 189733. In total we observed ten transits in 2006 and 2008 with 2.6-m Nordic Optical Telescope, two 2007 4.2-m William Herschel Telescope. used Markov-Chain Monte Carlo simulations to derive parameters their uncertainties, our results are good agreement previously published values. performed independent analyses residuals place upper mass limits on putative perturbing planets. The show no evidence for presence planets...
Conventional CCD detectors have two major disadvantages: they are slow to read out and suffer from noise. These problems combine make high-speed spectroscopy of faint targets the most demanding astronomical observations. It is possible overcome these weaknesses by using electron-multiplying CCDs (EMCCDs). EMCCDs conventional frame-transfer CCDs, but with an extended serial register containing high-voltage electrodes. An avalanche secondary electrons produced as photon-generated clocked...
MEGARA (<i>Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía</i>) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the 10.4m telescope in La Palma. offers two IFU fiber bundles, one covering 12.5x11.3 arcsec<sup>2</sup> with a spaxel size of 0.62 arcsec (Large Compact Bundle; LCB) another 8.5x6.7 0.42 (Small SCB). The MOS mode will allow observing up to 100 objects region 3.5x3.5 arcmin<sup>2</sup> around bundles. Both LCB capabilities...
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is an optical Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) designed for the 10.4m telescope in La Palma that being built by a Consortium led UCM (Spain) also includes INAOE (Mexico), IAA-CSIC (Spain), UPM (Spain). The instrument currently finishing AIV will be sent to on November 2016 its on-sky commissioning April 2017. IFU fiber bundle (LCB) covers 12.5x11.3 arcsec2 with spaxel size of 0.62 arcsec while...
Abstract We present high time-resolution spectroscopy of the eclipsing cataclysmic variable SDSS J143317.78+101123.3 obtained with QUCAM2, a high-speed/low-noise electron-multiplying CCD camera. Littlefair et al. measured mass secondary star in using light-curve fitting technique and value M2 = 0.060 ± 0.003 M⊙, making it one three first bona fide detections brown dwarf donor variable. In this Letter, we dynamical measurement supporting important result. radial velocity semi-amplitude white...
In these proceedings we give a summary of the characteristics and current status MEGARA instrument, future optical IFU MOS for 10.4-m Gran Telescopio Canarias (GTC). is being built by Consortium public research institutions led Universidad Complutense de Madrid (UCM, Spain) that also includes INAOE (Mexico), IAA-CSIC (Spain) UPM (Spain). The two different fiber bundles, one called LCB (Large Compact Bundle) with field-of-view 12.5×11.3 arcsec<sup>2</sup> spaxel size 0.62 arcsec yielding...
After completion of its final-design review last year, it is full steam ahead for the construction MOONS instrument - next generation multi-object spectrograph VLT. This remarkable will combine first time: 8 m collecting power VLT, 1000 optical fibres with individual robotic positioners and both medium- high-resolution spectral coverage acreoss wavelength range 0.65μm 1.8 μm. Such a facility allow veritable host Galactic, Extragalactic Cosmological questions to be addressed. In this paper we...
Infrared hybridized detectors are widely used in astronomy, and their performance can be degraded by image persistence. This results remnant images that persist the detector for many hours, contaminating any subsequent low-background observations. A different but related problem is reciprocity failure whereby less sensitive to low flux It demonstrated both of these problems explained trapping detrapping currents move charge back forward across depletion region boundary photodiodes within...
CARMENES is a fiber-fed high-resolution Echelle spectrograph for the Calar Alto 3.5m telescope. The instrument built by German-Spanish consortium under lead of Landessternwarte Heidelberg. search planets around M dwarfs with radial velocity 1 m/s main focus planned science. Two channels, one visible, another near-infrared, will allow observations in complete wavelength range from 550 to 1700 nm. To ensure stability, working vacuum thermally controlled environment. VIS channel covering...
On June 25th 2017, the new intermediate-resolution optical IFU and MOS of 10.4-m GTC had its first light. As part tests carried out to verify performance instrument in two modes (IFU MOS) 18 spectral setups (identical number VPHs with resolutions R=6000-20000 from 0.36 1 micron) a astronomical objects were observed. These observations show that MEGARA@GTC is called fill niche high-throughput, intermediateresolution extremely-faint narrow-lined objects. Lyman-α absorbers, star-forming dwarfs...
MEGARA is the new generation IFU and MOS optical spectrograph built for 10.4m Gran Telescopio CANARIAS (GTC). The project was developed by a consortium led UCM (Spain) that also includes INAOE (Mexico), IAA-CSIC UPM (Spain). instrument arrived to GTC on March 28th 2017 successfully integrated commissioned at telescope from May August 2017. During on-sky commissioning we demonstrated powerful robust provides intermediate-to-high spectral resolutions RFWHM ~ 6,000, 12,000 20,000 an...
The new L3 Technology CCDs from E2V allow detector read noise to be decoupled readout speed. If operated at sufficiently high gain, the drops sub-electron levels and photon counting becomes possible. At ING we have incorporated CCD60 , CCD87 CCD97 detectors into cryogenic cameras coupled SDSU controllers for a variety of tests both in lab on-sky using 4.2m William Herschel Telescope. These been proportional photon-counting mode an in-house Linux based DAS. We gained number insights...
Image persistence is a major problem in infrared detectors, potentially seriously limiting data quality many observational regimes. The manifests itself as remnant images that can persist for several days after deep exposure. In this study, the behavior of three 5.3um cutoff H2RGs has been characterised using low-background cryostat with LED light sources. Persistence charge de-trapping was measured over hours following wide range exposure levels and times. This then analysed to yield...
The new L3 Technology CCDs from E2V combine sub-electron read noise with high pixel rates. This makes them ideal candidates for wavefront sensing. ING's NAOMI adaptive optics instrument is currently limited by the readout of its sensor CCDs. Upgrading to detectors has potential give a large increase in performance; simulations suggest 2 magnitude improvement guide star limit. At ING we have explored behaviour various devices applications ranging fast photometry, spectroscopy through...
MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is the new integral field unit (IFU) and multi-object spectrograph (MOS) instrument for GTC. The subsystems include pseudo-slit, shutter, collimator with a focusing mechanism, pupil elements on volume phase holographic grating (VPH) wheel camera joined to cryostat through last lens, CCD detector inside. In this paper we describe full preliminary design of which will harbor spectrograph. selected cryogenic device an LN2...
Abstract Searching for transit timing variations in the known transiting exoplanet systems can reveal presence of other bodies system. Here we report such searches two systems, TrES-1 and WASP-2. Their new transits were observed with 4.2m William Herschel Telescope located on La Palma, Spain. In a continuing programme, three consecutive TrES-1, one WASP-2 during September 2007. We used Markov Chain Monte Carlo simulations to derive times their uncertainties. The resulting are consistent most...
Hawaii <italic>x</italic> Reference Guide (HxRG) detectors have crosstalk between amplifier channels at a scientifically relevant level. In principle, signals can be fully calibrated and removed from data but only if full matrix is measured for the detector. We present fast method of characterization that performed with most instrument calibration units. It requires flat-field illumination window programming in HxRG detectors. show matrices obtained this both slow modes an H2RG detector...
I have developed an IDL simulation of electron multiplying L3 (low light level) technology CCD that includes the effects clock induced charge and multiplication noise. This model allows observers interested in obtaining high time resolution photometry spectroscopy faint sources to compare more easily gains performance can be expected by switching detector. The has been used generate synthetic image sequences stars emission lines. stellar images are analysed show how measured centroid noise...
Noise modeling of an E2V CCD231 suggested that a weighted double correlated sampler (DCDS) processor could offer small noise improvements at low pixel rates. The model was used to produce synthetic video waveforms were then processed various ADC frequencies and analogue bandwidths identify the best weighting strategy preamplifier design. An FPGA-based DCDS controller built, first measure actual CCD spectrum verify earlier theoretical results.
The INT Prime Focus Mosaic Camera (INT PFC) is designed to provide a large field survey and supernovae search capability for the prime focus of 2.5 m Isaac Newton Telescope (INT). It joint collaboration between Royal Greenwich Observatory (UK), Kapteyn Sterrenwacht Werkgroep (Netherlands), Lawrence Berkeley Laboratories (USA). PFC consists 4 chip mosaic utilizing thinned anti-reflection coated CCDs. These are LORAL devices LICK3 design. They will be operated cryogenically in purpose built...
The GLAS (Ground-layer Laser Adaptive-optics System) project is to construct a common-user Rayleigh laser beacon that will work in conjunction with the existing NAOMI adaptive optics system, instruments (near IR imager INGRID, optical integral field spectrograph OASIS, coronagraph OSCA) and infrastructure at 4.2-m William Herschel Telescope (WHT) on La Palma. guide star system increase sky coverage available high-order from ~1% approaching 100% be optimized for scientific exploitation of...
GLAS is an upgrade of the William Herschel Telescope's existing natural-guide-star (NGS) AO system NAOMI to incorporate a 20-W Rayleigh laser guide star (LGS) projected altitude 15 km. It currently being commissioned on-sky, and we review here current status project. GLAS/NAOMI delivers dramatic improvements in PSF both near-IR (AO-corrected FWHM close diffraction limit, >~ 0.15 arcsec) optical (factor ~ 2 reduction FWHM). The performance similar that with NGS, consistent predictions from...