scholarly journals A fast radio burst with a low dispersion measure

Author(s):  
E Petroff ◽  
L C Oostrum ◽  
B W Stappers ◽  
M Bailes ◽  
E D Barr ◽  
...  
2021 ◽  
Vol 103 (10) ◽  
Author(s):  
Mukul Bhattacharya ◽  
Pawan Kumar ◽  
Eric V. Linder

2020 ◽  
Vol 494 (1) ◽  
pp. 1229-1236 ◽  
Author(s):  
Nicola T Locatelli ◽  
Gianni Bernardi ◽  
Germano Bianchi ◽  
Riccardo Chiello ◽  
Alessio Magro ◽  
...  

ABSTRACT Fast radio bursts (FRBs) remain one of the most enigmatic astrophysical sources. Observations have significantly progressed over the last few years, due to the capabilities of new radio telescopes and the refurbishment of existing ones. Here, we describe the upgrade of the Northern Cross radio telescope, operating in the 400–416 MHz frequency band, with the ultimate goal of turning the array into a dedicated instrument to survey the sky for FRBs. We present test observations of the pulsar B0329+54 to characterize the system performance and forecast detectability. Observations with the system currently in place are still limited by modest sky coverage (∼9.4 deg2) and biased by smearing of high dispersion measure events within each frequency channels. In its final, upgraded configuration, however, the telescope will be able to carry out unbiased FRB surveys over a ∼350 deg2 instantaneous field of view up to z ∼ 5, with a (nearly constant) $\sim 760 \, (\tau /{\rm ms})^{-0.5}$ mJy rms sensitivity.


Author(s):  
S Hackstein ◽  
M Brüggen ◽  
F Vazza

Abstract Context: Fast radio bursts are transient radio pulses of extragalactic origin. Their dispersion measure is indicative of the baryon content in the ionized intergalactic medium between the source and the observer. However, inference using unlocalized fast radio bursts is degenerate to the distribution of redshifts of host galaxies. Method: We perform a joint inference of the intergalactic baryon content and the fast radio burst redshift distribution with the use of Bayesian statistics by comparing the likelihood of different models to reproduce the observed statistics in order to infer the most likely models. In addition to two models of the intergalactic medium, we consider contributions from the local environment of the source, assumed to be a magnetar, as well as a representative ensemble of host and intervening galaxies. Results: Assuming that the missing baryons reside in the ionized intergalactic medium, our results suggest that the redshift distribution of observed fast radio bursts peaks at z ≲ 0.6. However, conclusions from different instruments regarding the intergalactic baryon content diverge and thus require additional changes to the observed distribution of host redshifts, beyond those caused by telescope selection effects.


2020 ◽  
Vol 496 (3) ◽  
pp. 3308-3313 ◽  
Author(s):  
Wenbin Lu ◽  
E Sterl Phinney

ABSTRACT When fast radio burst (FRB) waves propagate through the local (${\lesssim}\rm 1\, pc$) environment of the FRB source, electrons in the plasma undergo large-amplitude oscillations. The finite-amplitude effects cause the effective plasma frequency and cyclotron frequency to be dependent on the wave strength. The dispersion measure and rotation measure should therefore vary slightly from burst to burst for a repeating source, depending on the luminosity and frequency of the individual burst. Furthermore, free–free absorption of strong waves is suppressed due to the accelerated electrons’ reduced energy exchange in Coulomb collisions. This allows bright low-frequency bursts to propagate through an environment that would be optically thick to low-amplitude waves. Given a large sample of bursts from a repeating source, it would be possible to use the deficit of low-frequency and low-luminosity bursts to infer the emission measure of the local intervening plasma and its distance from the source. Information about the local environment will shed light on the nature of FRB sources.


2020 ◽  
Vol 497 (1) ◽  
pp. 125-129 ◽  
Author(s):  
Mieke Bouwhuis ◽  
Keith W Bannister ◽  
Jean-Pierre Macquart ◽  
R M Shannon ◽  
David L Kaplan ◽  
...  

ABSTRACT We report the results of the rapid follow-up observations of gamma-ray bursts (GRBs) detected by the Fermi satellite to search for associated fast radio bursts. The observations were conducted with the Australian Square Kilometre Array Pathfinder at frequencies from 1.2 to 1.4 GHz. A set of 20 bursts, of which four were short GRBs, were followed up with a typical latency of about 1 min, for a duration of up to 11 h after the burst. The data were searched using 4096 dispersion measure trials up to a maximum dispersion measure of 3763 pc cm−3, and for pulse widths w over a range of duration from 1.256 to 40.48 ms. No associated pulsed radio emission was observed above $26 \, {\rm Jy\, ms}\, (w/1\, {\rm ms})^{-1/2}$ for any of the 20 GRBs.


Nature ◽  
2020 ◽  
Vol 587 (7832) ◽  
pp. 43-44
Author(s):  
Amanda Weltman ◽  
Anthony Walters
Keyword(s):  

Nature ◽  
2020 ◽  
Vol 582 (7812) ◽  
pp. 322-323 ◽  
Author(s):  
Alexandra Witze

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