A5029441718- Radio Astronomy Observations and Technology
- Pulsars and Gravitational Waves Research
- Astrophysics and Cosmic Phenomena
- Antenna Design and Optimization
- Advanced Frequency and Time Standards
- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Superconducting and THz Device Technology
- Gamma-ray bursts and supernovae
- GNSS positioning and interference
- Astrophysical Phenomena and Observations
- Radio Wave Propagation Studies
- Stellar, planetary, and galactic studies
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Geophysics and Gravity Measurements
- Advanced Wireless Communication Techniques
- High-pressure geophysics and materials
South African Radio Astronomy Observatory
2019-2024
Stellenbosch University
2022-2023
SKA Telescope, South Africa
2018-2021
National Radio Astronomy Observatory
2016
Abstract We describe system verification tests and early science results from the pulsar processor (PTUSE) developed for newly commissioned 64-dish SARAO MeerKAT radio telescope in South Africa. is a high-gain ( ${\sim}2.8\,\mbox{K Jy}^{-1}$ ) low-system temperature ${\sim}18\,\mbox{K at }20\,\mbox{cm}$ array that currently operates 580–1 670 MHz can produce tied-array beams suitable observations. This paper presents MeerTime Large Survey Project commissioning with PTUSE. Highlights include...
The Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) has been working a decade to reduce the time cost of designing, building deploying new digital radio-astronomy instruments. Today, CASPER open-source technology powers over 45 scientific instruments worldwide, is used by scientists engineers at dozens academic institutions. In this paper, we catalog current offerings collaboration, past present built users developers. We describe ongoing state software...
We present the confusion-limited 1.28 GHz MeerKAT DEEP2 image covering one $\approx 68'$ FWHM primary beam area with $7.6''$ resolution and $0.55 \pm 0.01$ $\mu$Jy/beam rms noise. Its J2000 center position $\alpha=04^h 13^m 26.4^s$, $\delta=-80^\circ 00' 00''$ was selected to minimize artifacts caused by bright sources. introduce new 64-element array describe commissioning observations measure attenuation pattern, estimate telescope pointing errors, pinpoint $(u,v)$ coordinate errors offsets...
A new 1.4 GHz 19-element, dual-polarization, cryogenic phased array feed (PAF) radio astronomy receiver has been developed for the Robert C. Byrd Green Bank Telescope (GBT) as part of FLAG (Focal L-band Array GBT) project. Commissioning observations calibrator sources show that this lowest reported beamformed system temperature ($T_{\rm sys}$) normalized by aperture efficiency ($\eta$) any to date. The measured $T_{\rm sys}/\eta$ is $25.4 \pm 2.5$ K near 1350 MHz boresight beam, which...
Abstract We present the results of commissioning observations for a new digital beam-forming back end Focal plane L -band Array Robert C. Byrd Green Bank Telescope (FLAG), cryogenically cooled Phased Feed (PAF) with lowest measured T sys / η any PAF outfitted on radio telescope to date. describe custom software used apply weights raw element covariances create research-quality spectral-line images fine-channel mode, study stability beam over time, characterize FLAG’s sensitivity frequency...
A combination of the very low signal-to-noise ratio and large parameter space spanned by pulsar emissions makes detection a challenging task. Currently, brute force searches are often used for cyclostationary Gaussian model is assumed emissions. Higher-Order spectra offer high domains in problems where desired signal polluted noise. The presence nonzero higher-order spectral components bursts may alternative methods. This work presents review statistics offers motivation their use...
The details of the MeerKAT radio telescope’s time and frequency reference subsystem that enables sampling via low-jitter, low-drift microwave clock signals, absolute timing (≤5 ns accurate) are discussed. subsystem’s pulse per second transmission parts now fully qualified commissioned for ultra high (UHF) L-bands also provide a 100-MHz interface interfaces S-band receivers were installed. includes cable measurement system called Karoo array (KATS). Performance differences on different bands...
ABSTRACT While observations of the stationary component pulsar radio signals have in many ways formed basis our understanding pulsars, statistical deviations these contain information that has become increasingly relevant. Using high time–frequency resolution data from MeerKAT telescope, we study self-noise autocorrelation function six pulsars. The is used to investigate statistics observed on nanosecond time-scales and for five pulsars it found deviate expected form a Gaussian process....
In this paper, we describe the development of a new L-band (1.4 GHz) Cryogenic Phased Array Feed (PAF) system, referred to as GBT2 array. Results from initial measurements made with array are also presented. The PAF was developed for Green Bank Telescope (GBT) part Focal GBT (FLAG) project. During first stage work (Phase I), prototype cryogenic 19 element dual-polarized "Kite" dipole elements and tested on GBT. measured system temperature over efficiency (Tsys/ η) ratio bore sight beam Kite...
A tracking sensor system for precise telescope time realization called the Karoo Telescope Time (KTT), next generation precision radio astronomy is described in this article. This a key enabler timing science like transients, pulsar search and timing. Mark I real KTT-GNSS was already implemented verified needs to ensure receptor below <30ns level. Some aspects design algorithm testing II post facto KTT-UTC which has goal of <5ns herein. The also accurate daily intermediary sensors, based on...
Radio telescopes are becoming more powerful, with increased sensitivity to both astronomical and interfering sources. Various interference mitigation techniques exist, however they could be harmful the signal of interest, thus it is important develop new techniques. Majority radio sources considered have a Gaussian distribution which fully characterised using second-order power statistics. Higher-order statistics tool that can suppress noise, therefore if energy in higher domains form basis...
The discovery of new radio pulsars is a key science goal for many next generation telescopes. achievement this objective relies both on the use improved instrumental sensitivity and also novel signal processing techniques. MeerKAT an example telescope, emissions from pulsar are recorded using one its receivers tested activity in bispectrum. test confirms bispectral serves as proof concept future detection algorithms based non-Gaussian statistics.
The Collaboration for Astronomy Signal Processing and Electronics Research (CASPER) has been working a decade to reduce the time cost of designing, building deploying new digital radio-astronomy instruments. Today, CASPER open-source technology powers over 45 scientific instruments worldwide, is used by scientists engineers at dozens academic institutions. In this paper we catalog current offerings collaboration, past present built users developers. We describe ongoing state software...
Astronomical sources are characterised using second-order power statistics because they have Gaussian distributions. Spectral Kurtosis is a tool that can suppress noise and therefore be used as an interference mitigation technique. However, care should taken transient such pulsars may contain non-Gaussian components. This paper provides overview of the estimator how one obtains thresholds in order to apply The technique applied Vela pulsar data observed tied-array beamformer mode by MeerKAT...
In this paper, we describe the development of a new L-band (1.4 GHz) Cryogenic Phased Array Feed (PAF) system, referred to as GBT2 array. Results from initial measurements made with array are also presented. The PAF was developed for Green Bank Telescope (GBT) part Focal GBT (FLAG) project. During first stage work (Phase I), prototype cryogenic 19 element dual-polarized "Kite" dipole elements and tested on GBT. measured system temperature over efficiency ($T_{sys}/\eta$) ratio bore sight...
Polyphase filterbank data of the Vela pulsar is acquired using MeerKAT radio telescope and analysed second-order frequency-frequency polyspectrum. The lack components off non-stationary manifold indicates that process stationary over timescales 0.8 microseconds. Additionally, complex found to be circular thus requires only a small subset possible definitions higher-order moments in its characterisation.