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 ◽  
...  
Author(s):  
S. E. Tremblay ◽  
S. M. Ord ◽  
N. D. R. Bhat ◽  
S. J. Tingay ◽  
B. Crosse ◽  
...  

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.


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 ◽  
...  

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.


1967 ◽  
Vol 148 ◽  
pp. 511 ◽  
Author(s):  
M. A. Gordon ◽  
J. W. Warwick

Solar Physics ◽  
2014 ◽  
Vol 290 (1) ◽  
pp. 169-180 ◽  
Author(s):  
B. P. Da̧browski ◽  
M. Karlický ◽  
P. Rudawy

Author(s):  
Laura G. Spitler ◽  
Marina Berezina ◽  
David J. Champion ◽  
Ralph Eatough ◽  
Heino Falke ◽  
...  

2020 ◽  
Author(s):  
Kenzie Nimmo ◽  
Jason Hessels ◽  
Aard Keimpema ◽  
Anne Archibald ◽  
James Cordes ◽  
...  

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.


1990 ◽  
Author(s):  
Jeffrey S. Morgan ◽  
J. Gethyn Timothy ◽  
Andrew M. Smith ◽  
Robert J. Hill ◽  
David B. Kasle

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