scholarly journals The High Time and Frequency Resolution Capabilities of the Murchison Widefield Array

2015 ◽  
Vol 32 ◽  
Author(s):  
S. E. Tremblay ◽  
S. M. Ord ◽  
N. D. R. Bhat ◽  
S. J. Tingay ◽  
B. Crosse ◽  
...  
Keyword(s):  
Radio Emission ◽  
Time Resolution ◽  
High Time ◽  
Frequency Resolution ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Radio Telescopes ◽  
Initial Design ◽  
Imaging Telescope ◽  
Murchison Widefield Array

AbstractThe science cases for incorporating high time resolution capabilities into modern radio telescopes are as numerous as they are compelling. Science targets range from exotic sources such as pulsars, to our Sun, to recently detected possible extragalactic bursts of radio emission, the so-called fast radio bursts (FRBs). Originally conceived purely as an imaging telescope, the initial design of the Murchison Widefield Array (MWA) did not include the ability to access high time and frequency resolution voltage data. However, the flexibility of the MWA’s software correlator allowed an off-the-shelf solution for adding this capability. This paper describes the system that records the 100 μs and 10 kHz resolution voltage data from the MWA. Example science applications, where this capability is critical, are presented, as well as accompanying commissioning results from this mode to demonstrate verification.

scholarly journals High time resolution and polarization properties of ASKAP-localized fast radio bursts

2020 ◽  
Vol 497 (3) ◽  
pp. 3335-3350 ◽  
Author(s):  
Cherie K Day ◽  
Adam T Deller ◽  
Ryan M Shannon ◽  
Hao Qiu(邱昊) ◽  
Keith W Bannister ◽  
...  
Keyword(s):  
Time Resolution ◽  
Local Environment ◽  
High Time ◽  
Frequency Resolution ◽  
Host Galaxy ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Diverse Range ◽  
Scattering Time ◽  
The Impact

ABSTRACT Combining high time and frequency resolution full-polarization spectra of fast radio bursts (FRBs) with knowledge of their host galaxy properties provides an opportunity to study both the emission mechanism generating them and the impact of their propagation through their local environment, host galaxy, and the intergalactic medium. The Australian Square Kilometre Array Pathfinder (ASKAP) telescope has provided the first ensemble of bursts with this information. In this paper, we present the high time and spectral resolution, full polarization observations of five localized FRBs to complement the results published for the previously studied ASKAP FRB 181112. We find that every FRB is highly polarized, with polarization fractions ranging from 80 to 100 per cent, and that they are generally dominated by linear polarization. While some FRBs in our sample exhibit properties associated with an emerging archetype (i.e. repeating or apparently non-repeating), others exhibit characteristic features of both, implying the existence of a continuum of FRB properties. When examined at high time resolution, we find that all FRBs in our sample have evidence for multiple subcomponents and for scattering at a level greater than expected from the Milky Way. We find no correlation between the diverse range of FRB properties (e.g. scattering time, intrinsic width, and rotation measure) and any global property of their host galaxy. The most heavily scattered bursts reside in the outskirts of their host galaxies, suggesting that the source-local environment rather than the host interstellar medium is likely the dominant origin of the scattering in our sample.

scholarly journals A SEARCH FOR FAST RADIO BURSTS AT LOW FREQUENCIES WITH MURCHISON WIDEFIELD ARRAY HIGH TIME RESOLUTION IMAGING

2015 ◽  
Vol 150 (6) ◽  
pp. 199 ◽  
Author(s):  
S. J. Tingay ◽  
C. M. Trott ◽  
R. B. Wayth ◽  
G. Bernardi ◽  
J. D. Bowman ◽  
...  
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Low Frequencies ◽  
Resolution Imaging ◽  
Murchison Widefield Array

High Time-Resolution Studies of Jupiter's Radio Bursts

1967 ◽  
Vol 148 ◽  
pp. 511 ◽  
Author(s):  
M. A. Gordon ◽  
J. W. Warwick
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Radio Bursts

scholarly journals Fourier Analysis of Radio Bursts Observed with Very High Time Resolution

Solar Physics ◽  
2014 ◽  
Vol 290 (1) ◽  
pp. 169-180 ◽  
Author(s):  
B. P. Da̧browski ◽  
M. Karlický ◽  
P. Rudawy
Keyword(s):  
Fourier Analysis ◽  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Very High

scholarly journals The High Time Resolution Universe surveys for pulsars and fast transients

2012 ◽  
Vol 8 (S291) ◽  
pp. 29-34 ◽  
Author(s):  
Michael J. Keith
Keyword(s):  
Radio Telescope ◽  
Time Resolution ◽  
Gamma Ray ◽  
Galactic Plane ◽  
High Time ◽  
Frequency Resolution ◽  
High Time Resolution ◽  
Galactic Latitude ◽  
Millisecond Pulsars ◽  
Bank System

AbstractThe High Time Resolution Universe survey for pulsars and transients is the first truly all-sky pulsar survey, taking place at the Parkes Radio Telescope in Australia and the Effelsberg Radio Telescope in Germany. Utilising multibeam receivers with custom built all-digital recorders the survey targets the fastest millisecond pulsars and radio transients on timescales of 64 μs to a few seconds. The new multibeam digital filter-bank system at has a factor of eight improvement in frequency resolution over previous Parkes multibeam surveys, allowing us to probe further into the Galactic plane for short duration signals. The survey is split into low, mid and high Galactic latitude regions. The mid-latitude portion of the southern hemisphere survey is now completed, discovering 107 previously unknown pulsars, including 26 millisecond pulsars. To date, the total number of discoveries in the combined survey is 135 and 29 MSPs These discoveries include the first magnetar to be discovered by it's radio emission, unusual low-mass binaries, gamma-ray pulsars and pulsars suitable for pulsar timing array experiments.

scholarly journals Single Pulse Polarimetry of the Vela Pulsar

2000 ◽  
Vol 177 ◽  
pp. 257-260
Author(s):  
Jeffrey S. Kern ◽  
Timothy H. Hankins ◽  
Joanna M. Rankin
Keyword(s):  
Radio Emission ◽  
Time Resolution ◽  
Single Pulse ◽  
Time Dependent ◽  
High Time ◽  
Emission Region ◽  
High Time Resolution ◽  
Spectral Indices ◽  
Vela Pulsar

AbstractMulti-frequency, single-pulse polarimetric observations of the Vela pulsar have been made using the VLA. These high time resolution measurements allow us to probe the geometry, and the time dependent characteristics of the radio emission region. Evidence for multiple emission components with differing spectral indices is found.

Searching for fast radio bursts with the high time resolution universe: North survey

2017 ◽  
Author(s):  
Laura G. Spitler ◽  
Marina Berezina ◽  
David J. Champion ◽  
Ralph Eatough ◽  
Heino Falke ◽  
...  
Keyword(s):  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Radio Bursts

scholarly journals Microsecond polarimetry of the repeating FRB 20180916B

2020 ◽  
Author(s):  
Kenzie Nimmo ◽  
Jason Hessels ◽  
Aard Keimpema ◽  
Anne Archibald ◽  
James Cordes ◽  
...  
Keyword(s):  
Time Resolution ◽  
Position Angle ◽  
High Time ◽  
Dispersion Measure ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Signal To Noise ◽  
Propagation Effects ◽  
Local Medium ◽  
Very High

Abstract Fast radio bursts (FRBs) exhibit a wide variety of spectral, temporal and polarimetric properties, which can unveil clues into their emission physics and propagation effects in the local medium. FRBs are challenging to study at very high time resolution due to the precision needed to constrain the dispersion measure, signal-to-noise limitations, and also scattering from the intervening medium. Here we present the high-time-resolution (down to 1 μs) polarimetric properties of four 1.7-GHz bursts from the repeating FRB 20180916B, which were detected in voltage data during observations with the European VLBI Network. In these bursts we observe a range of emission timescales spanning three orders of magnitude, the shortest component width reaching 3-4 μs (below which we are limited by scattering). We demonstrate that all four bursts are highly linearly polarised (≥ 80%), show no evidence for significant circular polarisation (≤ 15%), and exhibit a constant polarisation position angle during and between bursts. On short timescales (≤ 100 μs), however, there appear to be subtle (few degree) polarisation position angle variations across the burst profiles. These observational results are most naturally explained in an FRB model where the emission is magnetospheric in origin, as opposed to models where the emission originates at larger distances in a relativistic shock.

scholarly journals Coherent Dedispersion: History and Results

2017 ◽  
Vol 13 (S337) ◽  
pp. 29-32
Author(s):  
Timothy H. Hankins
Keyword(s):  
Radio Emission ◽  
Real Time ◽  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Emission Mechanism ◽  
Real Time Processing ◽  
Time Processing ◽  
Pulsar Timing

AbstractThe high time resolution afforded by coherent dedispersion has enabled precision pulsar timing, detailed studies of pulsar morphology, and has led to conclusions about the radio emission mechanism. The advance of technology in the last 50 years has enhanced the capability of coherent dedispersion, now used for most pulsar observing, by nearly six orders of magnitude. Although coherent dedispersion is now done mostly in software, in “earlier days” several novel hardware devices for real-time processing were developed.

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