Nolan Denman
A5086013044- Radio Astronomy Observations and Technology
- Microwave Engineering and Waveguides
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Antenna Design and Optimization
- Superconducting and THz Device Technology
- Astrophysics and Cosmic Phenomena
- Astrophysical Phenomena and Observations
- Atomic and Subatomic Physics Research
- Galaxies: Formation, Evolution, Phenomena
- Particle accelerators and beam dynamics
- Radio Frequency Integrated Circuit Design
- Atmospheric and Environmental Gas Dynamics
- Electromagnetic Compatibility and Measurements
- Methane Hydrates and Related Phenomena
- Soil Moisture and Remote Sensing
- Earthquake Detection and Analysis
- Cosmology and Gravitation Theories
- GNSS positioning and interference
- Advanced Frequency and Time Standards
- Spectroscopy and Laser Applications
National Radio Astronomy Observatory
2020-2022
University of Toronto
2014-2022
Canadian Institute for Theoretical Astrophysics
2015-2020
Jet Propulsion Laboratory
2020
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a drift scan radio telescope operating across the 400-800 MHz band. CHIME located at Dominion Radio Astrophysical Observatory near Penticton, BC Canada. instrument designed to map neutral hydrogen over redshift range 0.8 2.5 constrain expansion history of Universe. This goal drives design features instrument. consists four parallel cylindrical reflectors, oriented north-south, each 100 m $\times$ 20 and outfitted with 256 element...
A pathfinder version of CHIME (the Canadian Hydrogen Intensity Mapping Experiment) is currently being commissioned at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC. The instrument a hybrid cylindrical interferometer designed to measure large scale neutral hydrogen power spectrum across redshift range 0.8 2.5. will be used baryon acoustic oscillation (BAO) this poorly probed where dark energy becomes significant contributor evolution Universe. revives cylinder design...
Abstract The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a novel transit radio telescope operating across the 400–800 MHz band. CHIME composed of four 20 m × 100 semicylindrical paraboloid reflectors, each which has 256 dual-polarization feeds suspended along its axis, giving it ≳200 deg 2 field view. This, combined with wide bandwidth, high sensitivity, and powerful correlator, makes an excellent instrument for detection fast bursts (FRBs). Fast Radio Burst Project (CHIME/FRB)...
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a transit interferometer currently being built at the Dominion Radio Astrophysical Observatory (DRAO) in Penticton, BC, Canada. We will use CHIME to map neutral hydrogen frequency range 400 { 800MHz over half of sky, producing measurement baryon acoustic oscillations (BAO) redshifts between 0.8 2.5 probe dark energy. have deployed pathfinder version that yield constraints on BAO power spectrum and provide test-bed for our...
We present results from a new incoherent-beam Fast Radio Burst (FRB) search on the Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder. Its large instantaneous field of view (FoV) and relative thermal insensitivity allow us to probe ultra-bright tail FRB distribution, test recent claim that this distribution's slope, $\alpha\equiv-\frac{\partial \log N}{\partial S}$, is quite small. A 256-input incoherent beamformer was deployed CHIME Pathfinder for purpose. If distribution...
We present the design and implementation of a custom GPU-based compute cluster that provides correlation X-engine CHIME Pathfinder radio telescope. It is among largest such systems in operation, correlating 32,896 baselines (256 inputs) over 400MHz bandwidth. Making heavy use consumer-grade parts software stack, system was developed at small fraction cost comparable installations. Unlike existing GPU backends, this built around OpenCL kernels running on consumer-level AMD GPUs, taking...
The CHIME Pathfinder is a new interferometric radio telescope that uses hybrid FPGA/GPU FX correlator. GPU-based X-engine of this correlator processes over 819 Gb/s 4+4-bit complex astronomical data from N=256 inputs across 400MHz band. A software framework presented to manage real-time flow, which allows each 16 processing servers handle 51.2 data, plus 8 ancillary data. Each server receives in the form UDP packets an FPGA F-engine eight 10 GbE links, combines these into large (32MB-256MB)...
We present the design, implementation and performance of a digital backend constructed for Canadian Hydrogen Intensity Mapping Experiment (CHIME) that uses accelerated computing to observe radio pulsars transient sources. When operating, CHIME correlator outputs 10 independent streams beamformed data CHIME/Pulsar digitally track specified celestial positions. Each these are processed by system which can coherently dedisperse, in real-time, up dispersion measure values 2500 pc/cm$^{-3}$ . The...
The Canadian Hydrogen Intensity Mapping Experiment (CHIME) Pathfinder radio telescope is currently surveying the northern hemisphere between 400 and 800 MHz. By mapping large scale structure of neutral hydrogen through its redshifted 21 cm line emission $z \sim 0.8-2.5$ CHIME will contribute to our understanding Dark Energy. Bright astrophysical foregrounds must be separated from signal, a task which requires precise characterization polarized beams. Using DRAO John A. Galt 26 m telescope,...
Interferometric radio telescopes often rely on computationally expensive O(N <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) correlation calculations; fortunately these computations map well to massively parallel accelerators such as low-cost GPUs. This paper describes the OpenCL kernels developed for GPU based X-engine of a new hybrid FX correlator. Channelized data from F-engine is supplied GPUs 4-bit, offset-encoded real and...
We present the implementation of a spectral kurtosis based Radio Frequency Interference detection system on CHIME instrument and its reduced-scale pathfinder. Our extends single-receiver formulations to case compact array, combining samples from multiple receivers improve confidence with which RFI is detected. Through comparison between on-sky data simulations, we show that statistical properties canonical estimator are functionally unchanged by cross-array integration. Moreover,...
The next generation Very Large Array (ngVLA) is a transformational radio observatory being designed by the U.S. National Radio Astronomy Observatory (NRAO). It will provide order of magnitude improvements in sensitivity, resolution, and uv coverage over current Jansky (VLA) at ~1.2-50 GHz extend frequency range up to 70-115 GHz. This document white paper written members Canadian community for 2020 Long Range Plan panel, which be making recommendations on Canada's future directions astronomy....
The CHIME Pathfinder is a new interferometric radio telescope that uses hybrid FPGA/GPU FX correlator. GPU-based X-engine of this correlator processes over 819 Gb/s 4+4-bit complex astronomical data from N=256 inputs across 400 MHz band. A software framework presented to manage real-time flow, which allows each 16 processing servers handle 51.2 data, plus 8 ancillary data. Each server receives in the form UDP packets an FPGA F-engine eight 10 GbE links, combines these into large (32MB-256MB)...
We present an overview of the Graphics Processing Unit (GPU)-based spatial processing system created for Canadian Hydrogen Intensity Mapping Experiment (CHIME). The design employs AMD S9300x2 GPUs and readily available commercial hardware in its nodes to provide a cost- power-efficient substrate. These are supported by liquid-cooling which allows continuous operation with modest power consumption all but most adverse conditions. Capable continuously correlating 2048 receiver-polarizations...
Interferometric radio telescopes often rely on computationally expensive O(N^2) correlation calculations; fortunately these computations map well to massively parallel accelerators such as low-cost GPUs. This paper describes the OpenCL kernels developed for GPU based X-engine of a new hybrid FX correlator. Channelized data from F-engine is supplied GPUs 4-bit, offset-encoded real and imaginary integers. Because low bit width data, two values may be packed into 32-bit register, allowing...
The Next-Generation Very Large Array (ngVLA) is a future radio astronomy facility, building on the existing in New Mexico, which promises an order of magnitude improvement over current capabilities terms sensitivity, angular and spectral resolutions. With 263 antennas up to thousands miles away, each one generating almost terabit-per-second data be processed real time, design Central Signal Processor for ngVLA project appears as formidable technical challenge. We propose SCalable,...
Radio-astronomical interferometers are superb instruments key to understanding our Universe and the physical laws that govern it. At core of such machines, a Central Signal Processor (CSP) combines information received from multiple antennas in real time by means cross-correlation beamforming. The CSP reduces input data rate several orders magnitude, so astronomical can be stored for offline processing. This paper makes case use SoC future radio astronomy as more environmentally sustainable...