scholarly journals LOFT-e: Localisation Of Fast Transients with e-MERLIN

2017 ◽  
Vol 13 (S337) ◽  
pp. 422-423
Author(s):  
C. R. H. Walker ◽  
R. P. Breton ◽  
P. A. Harrison ◽  
A. Holloway ◽  
M. J. Keith ◽  
...  
Keyword(s):  
Full Advantage ◽  
Real Time ◽  
Time Resolution ◽  
Observation Time ◽  
Field Of View ◽  
High Time ◽  
High Time Resolution ◽  
Radio Bursts ◽  
Raw Data ◽  
Fast Transients

AbstractThe majority of fast radio bursts (FRBs) are poorly localised, hindering their potential scientific yield as galactic, intergalactic, and cosmological probes. LOFT-e, a digital backend for the U.K.’s e-MERLIN seven-telescope interferometer will provide commensal search and real-time detection of FRBs, taking full advantage of its field of view (FoV), sensitivity, and observation time. Upon burst detection, LOFT-e will store raw data offline, enabling the sub-arcsecond localisation provided by e-MERLIN and expanding the pool of localised FRBs. The high-time resolution backend will additionally introduce pulsar observing capabilities to e-MERLIN.

scholarly journals High time resolution PFISR and optical observations of naturally enhanced ion acoustic lines

2009 ◽  
Vol 27 (4) ◽  
pp. 1457-1467 ◽  
Author(s):  
R. G. Michell ◽  
K. A. Lynch ◽  
C. J. Heinselman ◽  
H. C. Stenbaek-Nielsen
Keyword(s):  
High Resolution ◽  
Time Resolution ◽  
Acoustic Waves ◽  
Fast Moving ◽  
High Time ◽  
High Time Resolution ◽  
Ion Acoustic Waves ◽  
Raw Data ◽  
Ion Acoustic ◽  
Auroral Imaging

Abstract. Observations of naturally enhanced ion acoustic lines (NEIALs) taken with the Poker Flat Incoherent Scatter Radar (PFISR) using a mode with very high time resolution are presented. The auroral event took place over Poker Flat, Alaska on 8 February 2007 at 09:35 UT (~22:00 MLT), and the radar data are complemented by common-volume high-resolution auroral imaging. The NEIALs occurred during only one of the standard 15-s integration periods. The raw data of this time show very intermittent NEIALs which occur only during a few very short time intervals (≤1 s) within the 15-s period. The time sampling of the raw data, ~19 ms on average, allows study of the time development of the NEIALs, though there are indications that even finer time resolution would be of interest. The analysis is based on the assumption that the NEIAL returns are the result of Bragg scattering from ion-acoustic waves that have been enhanced significantly above thermal levels. The spectra of the raw data indicate that although the up- and down-shifted shoulders can both become enhanced at the same time, (within 19 ms), they are most often enhanced individually. The overall power in the up-and down-shifted shoulders is approximately equal throughout the event, with the exception of one time, when very large up-shifted power was observed with no corresponding down-shifted power. This indicates that during the 480 μs pulse, the strongly enhanced ion-acoustic waves were only traveling downward and not upward. The exact time that the NEIALs occurred was when the radar beam was on the boundary of a fast-moving (~10 km/s), bright auroral structure, as seen in the high resolution auroral imaging of the magnetic zenith. When viewed with high time resolution, the occurrence of NEIALs is associated with rapid changes in auroral luminosity within the radar field of view due to fast-moving auroral fine structures.

scholarly journals A real-time, all-sky, high time resolution, direct imager for the long wavelength array

2019 ◽  
Vol 486 (4) ◽  
pp. 5052-5060 ◽  
Author(s):  
James Kent ◽  
Jayce Dowell ◽  
Adam Beardsley ◽  
Nithyanandan Thyagarajan ◽  
Greg Taylor ◽  
...  
Keyword(s):  
Real Time ◽  
Time Resolution ◽  
High Time ◽  
High Time Resolution ◽  
Long Wavelength

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.

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

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 FRATs: Searching for Fast Radio Transients in Real Time with LOFAR

2011 ◽  
Vol 7 (S285) ◽  
pp. 411-413 ◽  
Author(s):  
S. ter Veen ◽  
P. Schellart ◽  
H. Falcke
Keyword(s):  
Real Time ◽  
Time Resolution ◽  
Field Of View ◽  
High Time Resolution ◽  
Wide Field ◽  
Crab Pulsar ◽  
Giant Pulse ◽  
Wide Field Of View ◽  
Trigger Algorithm ◽  
Radio Transients

AbstractThe aim of the FRATs project is to detect single dispersed pulses from Fast Radio Transients with LOFAR in real time. The pulses can originate from pulsars, RRATS and other classes of known or unknown objects. To detect the pulses a trigger algorithm is run on an incoherent beam from the different LOFAR stations. The beam has a wide field of view and can be formed parallel to other observations. A precise localisation is achieved by storing and processing off-line the data from each dipole, giving all-sky coverage with a spatial resolution of the order of arc-seconds. The source is identified by making high-time-resolution images. The method has been tested by detecting and identifying a giant pulse from the Crab pulsar.

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 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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