W. S. Holland
A5024654158- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Superconducting and THz Device Technology
- Astronomy and Astrophysical Research
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Radio Astronomy Observations and Technology
- Physics of Superconductivity and Magnetism
- Calibration and Measurement Techniques
- Astrophysical Phenomena and Observations
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Molecular Spectroscopy and Structure
- Astrophysics and Cosmic Phenomena
- Spacecraft and Cryogenic Technologies
- Gamma-ray bursts and supernovae
- Advanced MEMS and NEMS Technologies
- Advanced Queuing Theory Analysis
- Particle accelerators and beam dynamics
- Planetary Science and Exploration
- Thermal Radiation and Cooling Technologies
- Simulation Techniques and Applications
- Optical Coatings and Gratings
- Spectroscopy and Laser Applications
Royal Observatory
2013-2025
UK Astronomy Technology Centre
2013-2025
University of Edinburgh
2011-2025
Science and Technology Facilities Council
2015-2018
Edinburgh College
2014
City, University of London
2003-2010
Cardiff University
2006
University of North Texas
2004-2006
University of Hawaii at Hilo
1995-2004
London Business School
2004
The Submillimetre Common User Bolometer Array 2 (SCUBA-2) is an instrument operating on the 15-m James Clerk Maxwell Telescope, nominally consisting of 5120 bolometers in each two simultaneous imaging bands centred over 450 and 850 um. camera operated by scanning across sky recording data at a rate 200 Hz. As largest new generation multiplexed kilopixel bolometer cameras (sub)millimetre, SCUBA-2 analysis represents significant challenge. We describe production maps using Sub-Millimetre...
SCUBA-2 is a 10 000-bolometer submillimetre camera on the James Clerk Maxwell Telescope. The instrument commissioning was completed in 2011 September, and full science operations began October. To harness potential of this powerful new astronomical tool, calibration must be accurate well understood. end, algorithms for calculating line-of-sight opacity have been improved, derived atmospheric extinction relationships at both wavebands are presented. results from over 500 primary secondary...
Dust emission around the nearby star Eridani has been imaged using a new submillimeter camera (the Submillimetre Common-User Bolometer Array at James Clerk Maxwell Telescope). At an 850 μm wavelength, ring of dust is seen peaking 60 AU from and with much lower inside 30 AU. The mass least ~0.01 M⊕ in dust, while upper limit 0.4 molecular gas imposed by CO observations. total comparable to estimated amount material, 0.04-0.3 M⊕, comets orbiting solar system. most probable origin structure...
Using the MIPS instrument on Spitzer, we have searched for infrared excesses around a sample of 82 stars, mostly F, G, and K main-sequence field along with small number nearby M stars. These stars were selected their suitability future observations by variety planet-finding techniques. provide information asteroidal cometary material orbiting these data that can be correlated any planets may eventually found. We found significant excess 70 μm emission toward 12 Combined an earlier study,...
This paper describes a James Clerk Maxwell Telescope (JCMT) legacy survey that has been awarded roughly 500 hr of observing time to be carried out from 2007 2009. In this survey, we will map with SCUBA‐2 (Submillimetre Common‐User Bolometer Array 2) almost all the well‐known low‐mass and intermediate‐mass star‐forming regions within 0.5 kpc are accessible JCMT. Most these locations associated Gould Belt. From observations, produce flux‐limited snapshot star formation near Sun, providing...
In this paper, we present the first observations of Ophiuchus molecular cloud performed as part James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) with SCUBA-2 instrument.We demonstrate methods for combining these data previous HARP CO, Herschel, and IRAM N 2 H + in order to accurately quantify properties sources Ophiuchus.We produce a catalogue all found by SCUBA-2.We separate into protostars starless cores.We list cores perform full virial analysis, including external...
Debris discs are evidence of the ongoing destructive collisions between planetesimals, and their presence around stars also suggests that planets exist in these systems. In this paper, we present submillimetre images thermal emission from debris formed SCUBA-2 Observations Nearby Stars (SONS) survey, one seven legacy surveys undertaken on James Clerk Maxwell Telescope 2012 2015. The overall results survey presented form 850 μm (and 450 μm, where possible) fluxes for observed fields. Excess...
Abstract Recent Atacama Large Millimeter/submillimeter Array observations present mounting evidence for the presence of exocometary gas released within Kuiper Belt analogs around nearby main-sequence stars. This represents a unique opportunity to study their ice reservoir at younger ages when volatile delivery planets is most likely occur. We here detection CO J = 2-1 emission colocated with dust from cometary belt in 440 Myr old Fomalhaut system. Through spectrospatial filtering, we achieve...
We present the first results from B-fields In STar-forming Region Observations (BISTRO) survey, using Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2) camera, with its associated polarimeter (POL-2), on James Clerk Maxwell Telescope (JCMT) in Hawaii. discuss survey's aims and objectives. describe rationale behind questions which survey will aim to answer. The most important of these is role magnetic fields star formation process scale individual filaments cores dense regions. data...
We present first results from a submillimeter continuum survey of the Galactic center "central molecular zone" (CMZ), made with Submillimeter Common-User Bolometer Array (SCUBA) on James Clerk Maxwell Telescope. SCUBA's scan-map mode has allowed us to make extremely wide field maps thermal dust emission unprecedented speed and sensitivity. also discuss some issues related elimination artifacts in data. Our simultaneous 850/450 μm have total size approximately 28 × 05 (400 75 pc) elongated...
We report the detection of linear polarization from Sgr A* at 750, 850, 1350, and 2000 µm which confirms contribution synchrotron radiation. From lack longer wavelengths, it appears to arise in millimeter/submillimeter excess. There are large position angle changes between millimeter submillimeter results, these discussed terms a polarized dust various models. In model that best explains data, radiation excess is self-absorbed region becomes optically thin submillimeter. This implies arises...
New submillimeter images have been obtained of the dust disk around nearby K2 V star Eridani, with total data set now spanning 5 yr. These show distribution dusty debris generated by comet collisions, reflecting clearing and perturbations planets, may give insights to early conditions in solar system. The structure seen Eri at 850 μm published 1998 is confirmed new observations, same also an image for first time 450 μm. inclined ≈25° sky plane, emission peaking 65 AU, a 105 AU radius outer...
We present the first published maps of magnetic fields in prestellar cores to test theoretical ideas about way which field geometry affects star formation process. The observations are JCMT-SCUBA λ850 μm thermal emission from dust. Linear polarizations at typically 10 or more independent positions each three objects, L1544, L183, and L43, were measured, geometries plane sky mapped polarization directions. observed all objects appear smooth fairly uniform. In L1544 L183 mean an angle ~30°...
We present high spatial resolution mid- and far-infrared images of the Vega debris disk obtained with Multiband Imaging Photometer for Spitzer (MIPS). The is well resolved, its angular size much larger than found previously. radius at least 43'' (330 AU), 70'' (543 105'' (815 AU) in extent 24, 70, 160 μm, respectively. are circular, smooth, without clumpiness all three wavelengths. radial surface brightness profiles follow power laws r-3 or r-4 imply an inner boundary a 11'' ± 2'' (86 AU)....
An excess of far-infrared emission is seen towards the nearby G8 V star τ Ceti, and this has been attributed to orbiting dust particles generated in planetesimal collisions. A new 850-µm image shows that there indeed such a debris disc, extending out ≈55 au (15 arcsec) radius. This first disc around Sun-like late main-sequence age be confirmed by imaging. The mass at least an order magnitude greater than Kuiper Belt, although dimensions systems are very similar Ceti exceeds Sun. Modelling...
New submillimeter images of the cold dust emission around nearby main-sequence star Fomalhaut are presented. Observations at a wavelength 450 ?m, where telescope beam size is equivalent to resolution 50 AU, reveal that encircled by significantly nonaxisymmetric inclined ring. Smooth axisymmetric models ring suggest existence least one clump with an estimated flux about 5% total from disk, thus implying mass 0.075 lunar masses. At data, this could instead be arc. The most plausible...
We present results from the earliest observations of DEBRIS, a <i>Herschel<i/> key programme to conduct volume- and flux-limited survey for debris discs in A-type through M-type stars. PACS images (from chop/nod or scan-mode observations) at 100 160 <i>μ<i/>m are presented toward two stars one F-type star: <i>β<i/> Leo, UMa <i>η<i/> Corvi. All three known disc hosts. spatially resolves dust emission around all (marginally, case UMa), providing new information about as close 11 pc with sizes...
Context. Fomalhaut is a young (2 ± 1 × 108 years), nearby (7.7 pc), 2 M⊙ star that suspected to harbor an infant planetary system, interspersed with one or more belts of dusty debris.
New detections of debris discs at submillimetre wavelengths present highly valuable complementary information to prior observations these sources shorter wavelengths. Characterization through spectral energy distribution modelling including the fluxes is essential for our basic understanding disc mass and temperature, presents a starting point further studies using millimetre interferometric observations. In framework ongoing SCUBA-2 Observations Nearby Stars, instrument on James Clerk...
Until recently, only a handful of dusty, star-forming galaxies (DSFGs) were known at $z>4$, most them significantly amplified by gravitational lensing. Here, we have increased the number such DSFGs substantially, selecting from uniquely wide 250-, 350- and 500-$μ$m Herschel-ATLAS imaging survey on basis their extremely red far-infrared colors faint flux densities - ergo they are expected to be largely unlensed, luminous, rare very distant. The addition ground-based continuum photometry...
We present models of the submillimetre dust emission around four Vega-excess stars. The results are adjusted to fit simultaneously spectral energy distribution from millimetre through optical wavelengths, as well image. combination spatially resolved images with continuum fluxes over a range wavelengths can remove some previous ambiguities in estimating characteristics and circumstellar distributions. Fomalhaut shows brightest best-resolved image, so gives most unambiguous fit. Both imaging...
SCUBA-2 is an innovative 10,000 pixel submillimeter camera due to be delivered the James Clerk Maxwell Telescope in late 2006. The expected revolutionize astronomy terms of ability carry out wide-field surveys unprecedented depths addressing key questions relating origins galaxies, stars and planets. This paper presents update on project with particular emphasis laboratory commissioning instrument. assembly integration will described as well measured thermal performance A summary results...
We present the results of dust emission polarization measurements Ophiuchus-B (Oph-B) carried out using Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on James Clerk Maxwell Telescope (JCMT) in Hawaii. This work is part B-fields In Star-forming Region Observations (BISTRO) survey initiated to understand role magnetic fields star formation for nearby star-forming molecular clouds. a first look at geometry and strength Oph-B. The field...