A5046360767- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Gamma-ray bursts and supernovae
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Astrophysics and Star Formation Studies
- Distributed and Parallel Computing Systems
- Astrophysics and Cosmic Phenomena
- Nuclear reactor physics and engineering
- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Nuclear Engineering Thermal-Hydraulics
- Optical measurement and interference techniques
- Image and Object Detection Techniques
- Nuclear Materials and Properties
- Astrophysical Phenomena and Observations
University of Wyoming
2015-2019
Durham University
2013-2016
Queen Mary University of London
2011-2012
The University of Adelaide
2007
University of Utah
2007
Studying quasars at the highest redshifts can constrain models of galaxy and black hole formation, it also probes intergalactic medium in early universe. Optical surveys have to date discovered more than 60 up z~6.4, a limit set by use z-band CCD detectors. Only one z>6.4 quasar has been discovered, namely z=7.08 ULAS J1120+0641, using near-infrared imaging. Here we report discovery three new 332 square degrees Visible Infrared Survey Telescope for Astronomy Kilo-degree Galaxy (VIKING)...
ABSTRACT We present ALMA detections of the [C ii ] 158 μ m emission line and underlying far-infrared (FIR) continuum three quasars at 6.6 < z 6.9 selected from VIKING survey. The fluxes range between 1.6 3.4 Jy km s −1 ([C luminosities ∼(1.9–3.9) × 10 9 L ⊙ ). measure flux densities 0.56–3.29 mJy around (rest frame), with implied FIR (0.6–7.5) 12 dust masses M d = (0.7–24) 8 . In one quasar we derive a temperature <?CDATA ${30}_{-9}^{+12}$?> <?MML <mml:math> <mml:msubsup> <mml:mrow>...
The VLT Survey Telescope (VST) ATLAS is an optical ugriz survey aiming to cover ~4700deg^2 of the Southern sky similar depths as Sloan Digital Sky (SDSS). From reduced images and object catalogues provided by Cambridge Astronomical Surveys Unit we first find that median seeing ranges from 0.8 arcsec FWHM in i 1.0 u, significantly better than 1.2-1.5 for SDSS. 5 sigma magnitude limit stellar sources r_AB=22.7 all bands these limits are at least faint SDSS more equivalent galaxy photometry...
We present the results of our first year quasar search in on-going ESO public Kilo Degree Survey (KiDS) and VISTA Kilo-Degree Infrared Galaxy (VIKING) surveys. These surveys are among deeper wide-field that can be used to uncovered large numbers z~6 quasars. This allows us probe a more common population quasars is fainter than well-studied from main Sloan Digital Sky Survey. From this set combined survey catalogues covering ~250 deg^2 we selected point sources down Z_AB=22 had very red i-Z...
Abstract We present ALMA band 3 observations of the CO(6–5), CO(7–6), and [C i ] 369 μ m emission lines in three highest-redshift quasar host galaxies at <?CDATA $6.6\lt z\lt 6.9$?> . These measurements constitute CO detections to date. The target quasars have previously been detected ii 158 underlying FIR dust continuum. detect (spatially unresolved, a resolution >2″, or ≳14 kpc) all hosts. In two sources, we continuum around 400 (rest-frame), one source low significance. derive...
We present the discovery of two z > 6 quasars, selected as i band dropouts in VST ATLAS survey. Our first quasar has redshift, = 6.31 \pm 0.03, magnitude, z_AB 19.63 0.08 and rest frame 1450A absolute M_1450 -27.8 0.2, making it joint second most luminous known at 6. The 6.02 19.54 -27.0 0.1. also recover a 5.86 discovered by Venemans et al. (2015, prep.). To select our quasars we use new 3D colour space, combining optical colours with mid-infra-red data from Wide-field Infrared Survey...
Abstract This is the third paper in a series aimed at finding reionization-era quasars with combination of DESI Legacy imaging Surveys (DELS), Pan-STARRS1 (PS1) Survey, and near-infrared surveys, such as UKIRT Hemisphere Survey (UHS), well Wide-field Infrared Explorer ( WISE ) mid-infrared survey. In this paper, we describe updated quasar candidate selection procedure, report discovery 16 6.4 ≲ z 6.9 from an area ∼13,020 deg 2 , present luminosity function (QLF) ∼ 6.7. The measured QLF...
We present the first discoveries from a survey of $z\gtrsim6$ quasars using imaging data DECam Legacy Survey (DECaLS) in optical, UKIRT Deep Infrared Sky (UKIDSS) and preliminary version Hemisphere (UHS) near-IR, ALLWISE mid-IR. DECaLS will image 9000 deg$^2$ sky down to $z_{\rm AB}\sim23.0$, UKIDSS UHS, which map northern at $0<DEC<+60^{\circ}$, reaching $J_{\rm VEGA}\sim19.6$ (5-$\sigma$). The combination these datasets allows us discover redshift $z\gtrsim7$ conduct complete census faint...
Recently, Carnall et al. discovered two bright high redshift quasars using the combination of VST ATLAS and WISE surveys. The technique involved 3-D colour plane i-z:z-W1:W1-W2 with W1 (3.4 micron) W2 (4.5 bands taking place usual NIR J band to help decrease stellar dwarf contamination. Here we report on our continued search for 5.7<z<6.4 over an ~2x larger area ~3577 sq. deg. Southern Hemisphere. We have found further z>6 quasars, VST-ATLAS J158.6938-14.4211 at z=6.07 J332.8017-32.1036...
Abstract The Beijing–Arizona Sky Survey (BASS) is a wide and deep imaging survey that covers 5400 deg 2 area in the northern Galactic cap with 2.3 m Bok telescope using two filters ( g r bands). Mosaic z -band Legacy (MzLS) same band 4 Mayall telescope. These surveys will be used for spectroscopic targeting by Dark Energy Spectroscopic Instrument (DESI) northernmost portion of DESI footprint. This paper describes third data release (DR3) BASS, which contains photometric from all BASS MzLS...
We identify near-infrared Ks band counterparts to Herschel-ATLAS sub-mm sources, using a preliminary object catalogue from the VISTA VIKING survey. The sources are selected H-ATLAS Phase 1 of GAMA 9h field, which includes all objects detected at 250, 350 or 500 um with SPIRE instrument. apply and discuss likelihood ratio (LR) method for candidates within search radius 10" 22,000 5 sigma detection 250 um. find that 11,294(51%) have best counterpart reliability $R\ge 0.8$, false identification...
We present a new redshift survey, the 2dF Quasar Dark Energy Survey pilot (2QDESp), which consists of ≈10 000 quasars from ≈150 deg2 southern sky, based on VST-ATLAS imaging and 2dF/AAOmega spectroscopy. Combining our optical photometry with WISE (W1,W2) bands we can select essentially contamination free quasar samples 0.8 < z 2.5 g 20.5. At fainter magnitudes, UVX selection is still required to reach ≈ 22.5 limit. Using both these techniques observed redshifts at sky densities up 90 deg−2....
The rare close projection of two quasars on the sky provides opportunity to study host galaxy environment a foreground quasar in absorption against continuum emission background quasar. For over decade "Quasars probing quasars" series has utilized this technique further understanding formation and evolution presence at z>2, resolving scales as small galactic disc from bound gas circumgalactic medium diffuse environs intergalactic space. Presented here, is public release pair spectral...
The European Southern Observatory's (ESO) Visible and Infrared Survey Telescope for Astronomy (VISTA) is a 4-m class survey telescope wide-field near-infrared imaging. VISTA currently running suite of six public surveys, which will shortly deliver their first Europe wide data releases to ESO. Kilo-degree Galaxy (VIKING) forms natural intermediate between current shallow deeper more concentrated by targeting two patches totalling 1500 deg2 in the Northern hemispheres with measured 5σ limiting...
This paper describes the second data release (DR2) of Beijing–Arizona Sky Survey (BASS). BASS is an imaging survey covering a 5400 deg2 footprint in g and r bands using 2.3 m Bok telescope. DR2 includes observations through 2017 July obtained by Mayall z-band Legacy (MzLS), which used 4 telescope to observe same footprint. MzLS have completed 72% 76% their observations. The two surveys will be served for spectroscopic targeting upcoming Dark Energy Spectroscopic Instrument. Both are reduced...