scholarly journals The performance and calibration of the CRAFT fly’s eye fast radio burst survey

2019 ◽  
Vol 36 ◽  
Author(s):  
C. W. James ◽  
K. W. Bannister ◽  
J.-P. Macquart ◽  
R. D. Ekers ◽  
S. Oslowski ◽  
...  
Keyword(s):  
Radio Burst ◽  
Phased Array ◽  
Radio Frequency Interference ◽  
Radio Bursts ◽  
System Noise ◽  
Fast Transients ◽  
Fast Radio Burst ◽  
Power Law Index ◽  
Phased Array Feeds ◽  
Best Fit

AbstractThe Commensal Real-time Australian Square Kilometre Array Pathfinder Fast Transients survey is the first extensive astronomical survey using phased array feeds. Since January 2017, it has been searching for fast radio bursts in fly’s eye mode. Here, we present a calculation of the sensitivity and total exposure of the survey that detected the first 20 of these bursts, using the pulsars B1641-45 and B0833-45 as calibrators. The beamshape, antenna-dependent system noise, and the effects of radio-frequency interference and fluctuations during commissioning are quantified. Effective survey exposures and sensitivities are calculated as a function of the source counts distribution. Statistical ‘stat’ and systematics ‘sys’ effects are treated separately. The implied fast radio burst rate is significantly lower than the 37 sky−1 day−1 calculated using nominal exposures and sensitivities for this same sample by Shannon et al. (2018). At the Euclidean (best-fit) power-law index of −1.5 (−2.2), the rate is $12.7_{-2.2}^{+3.3}$ (sys) ± 3.6 (stat) sky−1 day−1 ( $20.7_{-1.7}^{+2.1}$ (sys) ± 2.8 (stat) sky−1 day−1) above a threshold of 56.6 ± 6.6(sys) Jy ms (40.4 ± 1.2(sys) Jy ms). This strongly suggests that these calculations be performed for other FRB-hunting experiments, allowing meaningful comparisons to be made between them.

scholarly journals Multiwavelength Observations of Fast Radio Bursts

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 76
Author(s):  
Luciano Nicastro ◽  
Cristiano Guidorzi ◽  
Eliana Palazzi ◽  
Luca Zampieri ◽  
Massimo Turatto ◽  
...  
Keyword(s):  
Radio Burst ◽  
High Energy ◽  
Medium Size ◽  
Radio Bursts ◽  
Starting Point ◽  
Key Points ◽  
Fast Radio Burst ◽  
Theoretical Results ◽  
Observational Strategy ◽  
Shed Light

The origin and phenomenology of the Fast Radio Burst (FRB) remains unknown despite more than a decade of efforts. Though several models have been proposed to explain the observed data, none is able to explain alone the variety of events so far recorded. The leading models consider magnetars as potential FRB sources. The recent detection of FRBs from the galactic magnetar SGR J1935+2154 seems to support them. Still, emission duration and energetic budget challenge all these models. Like for other classes of objects initially detected in a single band, it appeared clear that any solution to the FRB enigma could only come from a coordinated observational and theoretical effort in an as wide as possible energy band. In particular, the detection and localisation of optical/NIR or/and high-energy counterparts seemed an unavoidable starting point that could shed light on the FRB physics. Multiwavelength (MWL) search campaigns were conducted for several FRBs, in particular for repeaters. Here we summarize the observational and theoretical results and the perspectives in view of the several new sources accurately localised that will likely be identified by various radio facilities worldwide. We conclude that more dedicated MWL campaigns sensitive to the millisecond–minute timescale transients are needed to address the various aspects involved in the identification of FRB counterparts. Dedicated instrumentation could be one of the key points in this respect. In the optical/NIR band, fast photometry looks to be the only viable strategy. Additionally, small/medium size radiotelescopes co-pointing higher energies telescopes look a very interesting and cheap complementary observational strategy.

scholarly journals No Evidence for Galactic Latitude Dependence of the Fast Radio Burst Sky Distribution

2021 ◽  
Vol 923 (1) ◽  
pp. 2 ◽  
Author(s):  
A. Josephy ◽  
P. Chawla ◽  
A. P. Curtin ◽  
V. M. Kaspi ◽  
M. Bhardwaj ◽  
...  
Keyword(s):  
Radio Burst ◽  
Sensitivity Threshold ◽  
Galactic Latitude ◽  
Radio Bursts ◽  
Intensity Mapping ◽  
Latitude Dependence ◽  
Kolmogorov Smirnov ◽  
Coin Flipping ◽  
Fast Radio Burst ◽  
Anderson Darling

Abstract We investigate whether the sky rate of fast radio bursts (FRBs) depends on Galactic latitude using the first catalog of FRBs detected by the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) Project. We first select CHIME/FRB events above a specified sensitivity threshold in consideration of the radiometer equation, and then we compare these detections with the expected cumulative time-weighted exposure using Anderson–Darling and Kolmogorov–Smirnov tests. These tests are consistent with the null hypothesis that FRBs are distributed without Galactic latitude dependence (p-values distributed from 0.05 to 0.99, depending on completeness threshold). Additionally, we compare rates in intermediate latitudes (∣b∣ < 15°) with high latitudes using a Bayesian framework, treating the question as a biased coin-flipping experiment–again for a range of completeness thresholds. In these tests the isotropic model is significantly favored (Bayes factors ranging from 3.3 to 14.2). Our results are consistent with FRBs originating from an isotropic population of extragalactic sources.

scholarly journals PAFINDER – Searching for FRBs and pulsars using Phased Array Feeds

2017 ◽  
Vol 13 (S337) ◽  
pp. 370-371
Author(s):  
Mateusz Malenta ◽  
Ewan Barr ◽  
Aaron Chippendale ◽  
Xinping Deng ◽  
Daniel George ◽  
...  
Keyword(s):  
Real Time ◽  
Radio Telescope ◽  
Phased Array ◽  
Single Pulse ◽  
Radio Bursts ◽  
Pulse Detection ◽  
Phased Array Feeds

AbstractThe challenges of detecting and localising Fast Radio Bursts in real time can be met with the use of Phased Array Feeds. One such system, capable of creating up to 36 simultaneous beams, is currently being commissioned at the Effelsberg radio telescope in Germany following testing at the 64 m Parkes radio telescope. The PAFINDER (Phased Array Feed FRB Finder) pipeline will be used with this receiver to enable real–time single–pulse detection and localisation.

scholarly journals A Decade and a Half of Fast Radio Burst Observations

Universe ◽  
2021 ◽  
Vol 7 (11) ◽  
pp. 453
Author(s):  
Manisha Caleb ◽  
Evan Keane
Keyword(s):  
Magnetic Field ◽  
Radio Burst ◽  
Line Of Sight ◽  
Radio Bursts ◽  
Radio Observations ◽  
The Past ◽  
Interstellar Media ◽  
Propagation Effects ◽  
Fast Radio Burst ◽  
The Universe

Fast radio bursts (FRBs) have a story which has been told and retold many times over the past few years as they have sparked excitement and controversy since their pioneering discovery in 2007. The FRB class encompasses a number of microsecond- to millisecond-duration pulses occurring at Galactic to cosmological distances with energies spanning about 8 orders of magnitude. While most FRBs have been observed as singular events, a small fraction of them have been observed to repeat over various timescales leading to an apparent dichotomy in the population. ∼50 unique progenitor theories have been proposed, but no consensus has emerged for their origin(s). However, with the discovery of an FRB-like pulse from the Galactic magnetar SGR J1935+2154, magnetar engine models are the current leading theory. Overall, FRB pulses exhibit unique characteristics allowing us to probe line-of-sight magnetic field strengths, inhomogeneities in the intergalactic/interstellar media, and plasma turbulence through an assortment of extragalactic and cosmological propagation effects. Consequently, they are formidable tools to study the Universe. This review follows the progress of the field between 2007 and 2020 and presents the science highlights of the radio observations.

scholarly journals Young magnetars with fracturing crusts as fast radio burst repeaters

2019 ◽  
Vol 488 (4) ◽  
pp. 5887-5897 ◽  
Author(s):  
A G Suvorov ◽  
K D Kokkotas
Keyword(s):  
Statistical Analysis ◽  
Power Law ◽  
Radio Burst ◽  
Rapid Evolution ◽  
Compact Objects ◽  
Tectonic Activity ◽  
Radio Bursts ◽  
Crustal Field ◽  
Long Time ◽  
Fast Radio Burst

Abstract Fast radio bursts are millisecond-duration radio pulses of extragalactic origin. A recent statistical analysis has found that the burst energetics of the repeating source FRB 121102 follow a power law, with an exponent that is curiously consistent with the Gutenberg–Richter law for earthquakes. This hints that repeat bursters may be compact objects undergoing violent tectonic activity. For young magnetars, possessing crustal magnetic fields which are both strong (B ≳ 1015 G) and highly multipolar, Hall drift can instigate significant field rearrangements even on ≲ century long time-scales. This reconfiguration generates zones of magnetic stress throughout the outer layers of the star, potentially strong enough to facilitate frequent crustal failures. In this paper, assuming a quake scenario, we show how the crustal field evolution, which determines the resulting fracture geometries, can be tied to burst properties. Highly anisotropic stresses are generated by the rapid evolution of multipolar fields, implying that small, localized cracks can occur sporadically throughout the crust during the Hall evolution. Each of these shallow fractures may release bursts of energy, consistent in magnitude with those seen in the repeating sources FRB 121102 and FRB 180814.J0422+73.

scholarly journals The Northern Cross fast radio burst project – I. Overview and pilot observations at 408 MHz

2020 ◽  
Vol 494 (1) ◽  
pp. 1229-1236 ◽  
Author(s):  
Nicola T Locatelli ◽  
Gianni Bernardi ◽  
Germano Bianchi ◽  
Riccardo Chiello ◽  
Alessio Magro ◽  
...  
Keyword(s):  
Radio Burst ◽  
System Performance ◽  
Field Of View ◽  
High Dispersion ◽  
Dispersion Measure ◽  
Radio Bursts ◽  
Radio Telescopes ◽  
Present Test ◽  
New Radio ◽  
Fast Radio Burst

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.

scholarly journals First Prompt Optical Observations of Nearest Fast Radio Burst new New Astromomical Method

2020 ◽  
Author(s):  
Vladimir Lipunov ◽  
V. Kornilov ◽  
E. Gorbovskoy ◽  
Kirill Zhirkov ◽  
Aristarkh Chasovnikov ◽  
...  
Keyword(s):  
Radio Burst ◽  
Gamma Ray ◽  
The Other ◽  
New Method ◽  
Optical Observations ◽  
Host Galaxy ◽  
Radio Range ◽  
Fast Transients ◽  
Fast Radio Burst ◽  
The Universe

Abstract With the discovery of gamma ray bursts1,2, it became clear that our Universe flickers with superfast catastrophic events, sometimes lasting for a thousandths of a second. These ultra-fast transients - the peculiar one-day butterflies of the Universe - shine so brightly that they are noticed even on the other end of the Universe and, moreover, by very small telescopes. But in the radio range, the sky remained silent until the beginning of the 21st century. Only in 2007, radio astronomers analyzing archival observations of the Parkes Radio Telescope first encountered fast transients 3,4 . About a hundred such sources have already been discovered. We report the first optical observation of the closest radio burster FRB 180916.J0158+655-8 synchronously with a radio burst. In total, we obtained about 155,093 images at MASTER Global Robotic Net9*. In the course of our observations, we found a new method for detecting objects deep below the noise level. In addition, using the new method, we found the excess of photons in the FRB direction at a level of 23 m associated with the emission of the host galaxy.

scholarly journals Astrometric accuracy of snapshot fast radio burst localisations with ASKAP

2021 ◽  
Vol 38 ◽  
Author(s):  
Cherie K. Day ◽  
Adam T. Deller ◽  
Clancy W. James ◽  
Emil Lenc ◽  
Shivani Bhandari ◽  
...  
Keyword(s):  
Reasonable Agreement ◽  
Signal To Noise Ratio ◽  
Host Galaxy ◽  
Radio Sources ◽  
Radio Bursts ◽  
Signal To Noise ◽  
Relative Separation ◽  
Fast Transients ◽  
Fast Radio Burst ◽  
Host Properties

Abstract The recent increase in well-localised fast radio bursts (FRBs) has facilitated in-depth studies of global FRB host properties, the source circumburst medium, and the potential impacts of these environments on the burst properties. The Australian Square Kilometre Array Pathfinder (ASKAP) has localised 11 FRBs with sub-arcsecond to arcsecond precision, leading to sub-galaxy localisation regions in some cases and those covering much of the host galaxy in others. The method used to astrometrically register the FRB image frame for ASKAP, in order to align it with images taken at other wavelengths, is currently limited by the brightness of continuum sources detected in the short-duration (‘snapshot’) voltage data captured by the Commensal Real-Time ASKAP Fast Transients (CRAFT) software correlator, which are used to correct for any frame offsets due to imperfect calibration solutions and estimate the accuracy of any required correction. In this paper, we use dedicated observations of bright, compact radio sources in the low- and mid-frequency bands observable by ASKAP to investigate the typical astrometric accuracy of the positions obtained using this so-called ‘snapshot’ technique. Having captured these data with both the CRAFT software and ASKAP hardware correlators, we also compare the offset distributions obtained from both data products to estimate a typical offset between the image frames resulting from the differing processing paths, laying the groundwork for future use of the longer duration, higher signal-to-noise ratio (S/N) data recorded by the hardware correlator. We find typical offsets between the two frames of ${\sim}0.6$ and ${\sim}0.3$ arcsec in the low- and mid-band data, respectively, for both RA and Dec. We also find reasonable agreement between our offset distributions and those of the published FRBs. We detect only a weak dependence in positional offset on the relative separation in time and elevation between target and calibrator scans, with the trends being more pronounced in the low-band data and in Dec. Conversely, the offsets show a clear dependence on frequency in the low band, which we compare to the frequency-dependent Dec. offsets found in FRB 200430. In addition, we present a refined methodology for estimating the overall astrometric accuracy of CRAFT FRBs.

Fast Radio Transients: From Pulsars to Fast Radio Bursts

2017 ◽  
Vol 14 (S339) ◽  
pp. 27-32
Author(s):  
B. W. Stappers ◽  
M. Caleb ◽  
L. N. Driessen
Keyword(s):  
Real Time ◽  
Time Scales ◽  
Radio Burst ◽  
Host Galaxy ◽  
Radio Bursts ◽  
Recent Developments ◽  
New Instrumentation ◽  
Fast Radio Burst ◽  
Radio Transients ◽  
Archived Data

AbstractThe radio sky is full of transients, their time-scales ranging from nanoseconds to decades. Recent developments in technology sensitivity and computing capabilities have opened up the short end of that range, and are revealing a plethora of new phenomenologies. Studies of radio transients were previously restricted to analyses of archived data, but are now including real-time analyses. We focus here on Fast Radio Bursts, discuss and compare the properties of the population, and describe what is to date the only known repeating Fast Radio Burst and its host galaxy. We also review what will be possible with the new instrumentation coming online.

scholarly journals Joint inference on the redshift distribution of fast radio burst and on the intergalactic baryon content

2020 ◽  
Author(s):  
S Hackstein ◽  
M Brüggen ◽  
F Vazza
Keyword(s):  
Radio Burst ◽  
Intergalactic Medium ◽  
Local Environment ◽  
Dispersion Measure ◽  
Selection Effects ◽  
Radio Bursts ◽  
Host Galaxies ◽  
Redshift Distribution ◽  
Joint Inference ◽  
Fast Radio Burst

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.

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