A5024376393- Adaptive optics and wavefront sensing
- Security and Verification in Computing
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Cloud Data Security Solutions
- Optical Systems and Laser Technology
- Information and Cyber Security
- Advanced Malware Detection Techniques
- Astrophysics and Star Formation Studies
- Atmospheric Ozone and Climate
- Access Control and Trust
- Distributed systems and fault tolerance
- Gamma-ray bursts and supernovae
- Advanced optical system design
- Advanced Data Storage Technologies
- Calibration and Measurement Techniques
- Infrared Target Detection Methodologies
- Astrophysics and Cosmic Phenomena
- Aerospace Engineering and Energy Systems
- Photocathodes and Microchannel Plates
- Optical Wireless Communication Technologies
- Particle Detector Development and Performance
- Network Security and Intrusion Detection
- Astronomical Observations and Instrumentation
- Internet Traffic Analysis and Secure E-voting
Durham University
2014-2024
Natural History Museum
2007-2022
Cardiff University
2015-2019
Netherlands Institute for Radio Astronomy
2015
Heidelberg University
2008-2015
United States Navy
2000-2014
United States Department of the Navy
2000-2014
Durham Technical Community College
2014
Naval Postgraduate School
2004-2010
The Parks Trust
2008
On galactic scales, the surface density of star formation appears to be well correlated with molecular gas. This has led many authors suggest that there exists a causal relationship between chemical state gas and its ability form stars – in other words, assumption must before can occur. We test this hypothesis by modelling within dense cloud properties similar small using series different models chemistry, ranging from one which molecules is not followed assumed remain atomic throughout,...
The Visible and Infrared Survey Telescope for Astronomy (VISTA) is the 4-m wide-field survey telescope at ESO’s Paranal Observatory, equipped with world’s largest near-infrared imaging camera (VISTA IR Camera, VIRCAM), 1.65 degree diameter field of view, 67 Mpixels giving 0.6 deg2 active pixel area, operating wavelengths 0.8−2.3 μm. We provide a short history project, an overview technical details full system including optical design, mirrors, structure, camera, optics, enclosure software....
We present 3D "zoom-in" simulations of the formation two molecular clouds out galactic interstellar medium. model - identified from SILCC with a resolution up to 0.06 pc using adaptive mesh refinement in combination chemical network follow heating, cooling, and H$_2$ CO including (self-) shielding. The are assembled within few million years mass growth rates $\sim$ 10$^{-2}$ M$_\mathrm{sun}$ yr$^{-1}$ final masses 50 000 M$_\mathrm{sun}$. A spatial $\lesssim$ 0.1 is required for convergence...
The Southern African Large Telescope (SALT) High Resolution Spectrograph (HRS) is a fibre-fed R4 échelle spectrograph employing white pupil design with red and blue channels for wavelength coverage from 370–890nm. instrument has four modes, each object sky fibres: Low (R~15000), Medium (R~40000) (R~65000), as well Stability mode enhanced radial velocity precision at R~65000. contains fibre double-scrambler offers optional simultaneous Th-Ar arc injection, or the inclusion of an iodine cell...
We describe the integration and test phase of construction VISTA Infrared Camera, a 64 Megapixel, 1.65 degree field view 0.9-2.4 micron camera which will soon be operating at cassegrain focus 4m telescope. The incorporates sixteen IR detectors six CCD are used to provide autoguiding wavefront sensing information telescope control system.
Complex organic molecules (COMs) are widely detected in protostellar and protoplanetary systems, where they thought to have been inherited large part from earlier evolutionary phases. The chemistry of COMs these phases, namely starless prestellar cores, remains poorly understood, as models often struggle reproduce the observed gas-phase abundances species. We simulate formation a molecular cloud, cores within it, out diffuse interstellar medium, follow chemical evolution cloud material...
The high-resolution échelle spectrograph, SALT HRS, is at an advanced stage of construction and will shortly become available to the user community Southern African Large Telescope (SALT). This paper presents a commentary on progress date gives instrument's final specification with refined estimates for its performance based initial testing optics science-grade detectors. It also contributes discussion how fibre input have been tailored specific scientific aspirations give four distinct...
SALT HRS is a fibre-fed, high dispersion échelle spectrograph currently being constructed for the Southern African Large Telescope (SALT). In this paper we highlight performance of key optical components, describe integration tasks that have taken place and present some first light results from laboratory. The instrument construction well advanced report on attainment required mechanical thermal stability provide measurement input optics (including fibre feed). initial alignment both optics,...
We introduce the histogram of oriented gradients (HOG), a tool developed for machine vision that we propose as new metric systematic characterization spectral line observations atomic and molecular gas study cloud formation models. In essence, HOG technique takes input extended spectral-line from two tracers provides an estimate their spatial correlation across velocity channels. characterized using synthetic H I 13 CO ( J = 1 → 0) emission numerical simulations magnetohydrodynamic (MHD)...
Recent advances in adaptive optics (AO) have led to the implementation of wide field-of-view AO systems. A number wide-field systems are also planned for forthcoming Extremely Large Telescopes. Such multiple wavefront sensors different types, and usually deformable mirrors (DMs). Here, we report on our experience integrating cameras DMs with real-time control two These CANARY, which has been operating on-sky since 2010, DRAGON, is a laboratory demonstrator instrument. We detail issues...
SALT HRS is a fiber-fed cross-dispersed echelle spectrograph designed for high resolution and efficiency seeing-limited spectroscopy on the Southern African Large Telescope. The spectrograph, which has dual channel white pupil design, uses single R4 grating, dichroic beam-splitter, volume phase holographic gratings as cross-dispersers. grating 41.6 grooves/mm illuminated with 200mm diameter beam. This allows R = 16,000 2.2" fiber complete wavelength coverage from 370 nm to 890 nm. Resolving...
American lobsters (Homarus americanus) are native to the east coast of North and Canada, but have been imported live into Europe for several decades resulting in their escape wild. potential a significant impact on European lobster gammarus) fisheries Europe, status is not well understood, especially Great Britain (GB) where reports sporadic. Reports were collated from across GB being caught coastal waters. Between 1988 2011, 26 individuals positively identified using standard taxonomic...
In April to May 2023, the superBIT telescope was lifted Earth's stratosphere by a helium-filled super-pressure balloon, acquire astronomical imaging from above (99.5% of) atmosphere. It launched New Zealand then, for 40 days, circumnavigated globe five times at latitude 50 degrees South. Attached were four 'DRS' (Data Recovery System) capsules containing 5 TB solid state data storage, plus GNSS receiver, Iridium transmitter, and parachute. Data copied these, two dropped over Argentina. They...
Results are presented of the properties a liquid crystal wavefront corrector for adaptive optics. The device is controlled using modal addressing in which case behaves more like continuous facesheet deformable mirror than segmented one. Furthermore, width and shape influence functions electrically controllable. We describe construction device, optical properties, we show experimental results low order aberration generation.
article Free AccessBITS: a smartcard protected operating system Authors: Paul C. Clark Trusted Information Systems, 3060 Washington Rd, Glenwood, MD MDView Profile , Lance J. Hoffman Department of Electrical Engineering and Computer Science, The George University, Washington, D.C. D.C.View Authors Info & Claims Communications the ACMVolume 37Issue 11Nov. 1994 pp 66–70https://doi.org/10.1145/188280.188371Published:01 November 1994Publication History 21citation917DownloadsMetricsTotal...
The multi-conjugate adaptive optics (MCAO) system design for the Gemini-South 8-meter telescope will provide near-diffraction-limited, highly uniform atmospheric turbulence compensation at near-infrared wavelengths over a 2 arc minute diameter field-of-view. includes three deformable mirrors optically conjugate to ranges of 0, 4.5, and 9.0 kilometers with 349, 468, 208 actuators, five 10-Watt-class sodium laser guide stars (LGSs) projected from launch located behind Gemini secondary mirror,...
A high assurance architecture is described for the protection of distributed multilevel secure computing environments from malicious code and other attacks. Component security services mechanisms extend interoperate with commodity PCs, client software, applications, trusted components, legacy single level networks, providing new capabilities composing secure, security. This results realization that unless a system offers users comfortable familiar interfaces handling routine information, it...
Abstract Image cubes of differential column density as a function dust temperature are constructed for Galactic Centre molecular cloud G0.253+0.016 (‘The Brick’) using the recently described PPMAP procedure. The input data consist continuum images from HerschelSpace Telescope in wavelength range 70–500 μm, supplemented by previously published interferometric at 1.3 mm wavelength. While bulk is consistent with being heated externally local interstellar radiation field, our image cube shows...
The Subarcsecond Telescope And BaLloon Experiment, STABLE, is the fine stage of a guidance system for high-altitude ballooning platform designed to demonstrate subarcsecond pointing stability over one minute using relatively dim guide stars in visible spectrum. STABLE uses an attitude rate sensor and motion star on detector control Fast Steering Mirror stabilize image. characteristics thermal-optical-mechanical elements directly affect quality point-spread function detector, so series...
We describe the implementation of a robotic SLODAR instrument at Cerro Paranal observatory. The measures vertical profile optical atmospheric turbulence strength, in 8 resolution elements, to maximum altitude ranging between 100 m and 500 m. present statistical results measurements on total 875 nights 2014 2018. ground layer is very varied, but median case most strength concentrated within first 50 altitude, with relatively weak higher altitudes up find good agreement seeing angle from DIMM...
Balloon-borne astronomy offers an attractive option for experiments that require precise pointing and attitude stabilization, due to a large reduction in the atmospheric interference observed by ground-based systems as well low-cost short development time-scale compared space-borne systems. The Imaging Testbed (BIT) is instrument designed meet technological requirements of high-precision astronomical missions, precursor facility-class with capabilities similar Hubble Space Telescope....
KMOS is a multi-object near-infrared integral field spectrograph being built by consortium of UK and German institutes. We report on the final integration test phases KMOS, its performance verification, prior to commissioning ESO VLT later this year.