Detection Of Fast Radio Bursts Research Articles

A study of two FRBs with low polarization fractions localized with the MeerTRAP transient buffer system

ABSTRACT Localization of fast radio bursts (FRBs) to arcsecond and subarcsecond precision maximizes their potential as cosmological probes. To that end, FRB detection instruments are deploying triggered complex-voltage capture systems to localize FRBs, identify their host galaxy, and measure a redshift. Here, we report the discovery and localization of two FRBs (20220717A and 20220905A) that were captured by the transient buffer system deployed by the MeerTRAP instrument at the MeerKAT telescope in South Africa. We were able to localize the FRBs to precision of $\sim$1 arcsecond that allowed us to unambiguously identify the host galaxy for FRB 20220717A (posterior probability $\sim$0.97). FRB 20220905A lies in a crowded region of the sky with a tentative identification of a host galaxy but the faintness and the difficulty in obtaining an optical spectrum preclude a conclusive association. The bursts show low linear polarization fractions (10–17 per cent) that conform to the large diversity in the polarization fraction observed in apparently non-repeating FRBs akin to single pulses from neutron stars. We also show that the host galaxy of FRB 20220717A contributes roughly 15 per cent of the total dispersion measure (DM), indicating that it is located in a plasma-rich part of the host galaxy which can explain the large rotation measure. The scattering in FRB 20220717A can be mostly attributed to the host galaxy and the intervening medium and is consistent with what is seen in the wider FRB population.

ALMA Reveals Spatially Resolved Properties of Molecular Gas in the Host Galaxy of FRB 20191001A at z = 0.2340

We report the detection of the CO(2–1) emission line with a spatial resolution of 0.″9 (3.5 kpc) from the host galaxy of the fast radio burst (FRB), FRB 20191001A at z = 0.2340, using the Atacama Large Millimeter/submillimeter Array. This is the first detection of spatially resolved CO emission from the host galaxy of an FRB at a cosmological distance. The inferred molecular gas mass of the host galaxy is (2.3 ± 0.4) × 1010 M ⊙, indicating that it is gas-rich, as evidenced by the measured molecular gas fraction μ gas = 0.50 ± 0.22. This molecular gas mass and the star formation rate of the host, SFR = (8.06 ± 2.42) M ⊙ yr−1, differ from those observed in the other FRB host galaxies with the average M gas = 9.6 × 108 M ⊙ and SFR = 0.90M ⊙ yr−1. This lends further credibility to the hypothesis that FRBs may originate from single or multiple progenitors across a diverse range of galaxy environments. Based on the observed velocity field modeling, we find that the molecular gas disk is dominated by an ordered circular rotation, despite the fact that the host galaxy has a gas-rich companion galaxy with a projected separation of ∼25 kpc. The formation of the FRB’s progenitor might not have been triggered by this interaction. We derive the 3σ upper limit of the molecular gas column density at the FRB detection site to be <2.1 × 1021 cm−2 with a 3σ upper limit.

An Ultra-Wideband Dual Polarization Antenna Array for the Detection and Localization of Bright Fast Radio Transients in the Milky Way

Fast radio bursts (FRBs) are extraordinary astrophysical phenomena characterized by short radio pulses that last only a few milliseconds, yet their power can surpass that of 500 million suns. To date, most detected FRBs originate from beyond our galaxy. However, if an FRB were to originate within the Milky Way, it could be detected using small antennas. In this paper, we propose a compact and ad-hoc antenna array designed for the efficient detection and localization of FRBs within the Milky Way. The antenna operates within the 1200–1800[Formula: see text]MHz range and consists of three sub-arrays placed in an L-shape for source localization, occupying a total volume of [Formula: see text]. Each sub-array consists of 4 miniaturized, dual-polarized, half-space radiation antenna elements, forming a one-dimensional array that allows shaping the radiation pattern to match the form of the Milky Way without exhibiting grating lobes. A prototype was constructed and characterized to validate the design. The measured results exhibit good agreement with the simulations. In addition to having a custom elongated radiation pattern, the array has attractive merits, such as low reflections at the input ports, high radiation efficiency, and a distribution that inhibits the existence of phase ambiguities, thus facilitating source localization.

Cosmic Baby and the Mystery of Fast Radio Bursts

With the discovery of “Pulsar” a new probe of short duration radio pulses arises to the astronomers. Searching the “tomography” of the galaxy using the short-pulses offered a new method to measure the fairly accurate distance to the new sources of pulse radiation i.e. Pulsars. Another pulse radiative object i.e. fast radio burst (FRB) remains a mysterious object till today. Analysis of observed data indicates that FRBs have multi-source origin, variation in location of the burst generation (i.e. radial distance from their central compact objects, the Magnetar’s surface) depending on model to model. Two most important puzzle creating facts of FRBs are: (a) microstructure appearance in FRBs on time-scale of ≤ 10 μs; (b) No FRBs observed at low latitudes. Recoding of observed parameters from Cosmic Baby, i.e. Swift J1818.0 – 1607, shows that it has a steep spectra at first and then flat spectra later which indicates possibly be a transient object between normal pulsars and magnetars. This unusual characteristic of radio spectrum provides a clue to rethink about the magnetar origin of FRBS. i.e. Cosmic Baby can be a probe of resolving the mangetar originated FRB problem. The author thus encourages the radio wave burst community for continuous observation through advanced radio telescopes ALMA, VLA, CHIME, UTMOST with a hope that detection of unseen FRBs at low latitudes unveil the secrets of the Universe.

Detecting Fast Radio Bursts with Spectral Structure Using the Continuous Forward Algorithm

Detecting fast radio bursts (FRBs) with frequency-dependent intensity remains a challenge, as existing search algorithms do not account for the spectral shape, potentially leading to nondetections. We propose a novel detection statistic, which we call the Kalman detector, that improves the sensitivity of FRB signal detection by incorporating spectral shape information. The detection statistic is based on an optimal matched filter, marginalizing over all possible intensity functions, weighted by a random walk probability distribution, considering some decorrelation bandwidth. Our analysis of previously detected FRBs demonstrates that the Kalman score provides a comparable yet independent source of information for bursts with significant spectral structure, and the sensitivity improvement is of the order 0%–200% with a median improvement of 20%. We also applied the Kalman detector to existing data from FRB 20201124A and detected two new repeat bursts that were previously missed. Furthermore, we suggest a practical implementation for real-time surveys by employing a low significance soft-trigger from initial flux integration-based detection algorithms. The Kalman detector has the potential to significantly enhance FRB detection capabilities and enable new insights into the spectral properties of these enigmatic astrophysical phenomena.

Flux Calibration of CHIME/FRB Intensity Data

Fast radio bursts (FRBs) are bright radio transients of microsecond to millisecond duration and unknown extragalactic origin. Central to the mystery of FRBs are their extremely high characteristic energies, which surpass the typical energies of other radio transients of similar duration, like Galactic pulsar and magnetar bursts, by orders of magnitude. Calibration of FRB-detecting telescopes for burst flux and fluence determination is crucial for FRB science, as these measurements enable studies of the FRB energy and brightness distribution in comparison to progenitor theories. The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a radio interferometer of cylindrical design. This design leads to a high FRB detection rate but also leads to challenges for CHIME/FRB flux calibration. This paper presents a comprehensive review of these challenges, as well as the automated flux calibration software pipeline that was developed to calibrate bursts detected in the first CHIME/FRB catalog, consisting of 536 events detected between 2018 July 25 and 2019 July 1. We emphasize that, due to limitations in the localization of CHIME/FRB bursts, flux and fluence measurements produced by this pipeline are best interpreted as lower limits, with uncertainties on the limiting value.

An Overview of FAST Real-time Fast Radio Burst Searching System

In this paper, we report a real-time Fast Radio Burst (FRB) searching system that has been successfully implemented with the 19 beam receiver of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The relatively small field of view of FAST makes the search for new FRBs challenging, but its high sensitivity significantly improves the accuracy of FRB localization and enables the detection of high-precision neutral hydrogen absorption lines generated by FRBs. Our goal is to develop an FRB searching system capable of real-time detection of FRBs that allows high-time resolution spectro-temporal studies among the repeated bursts, as well as detailed investigations of these bursts and exploration of FRB progenitor models. The data from each beam of the 19-beam receiver are fed into a high-performance computing node server, which performs real-time searches for pulses with a wide dispersion measure (DM) range of 20–10,000 pc cm−3 with step efficiency of 25% in real time. Then, the head node server aggregates all the candidate signals from each beam within a given time, determining their authenticity based on various criteria, including arrival time, pulse width, signal-to-noise ratio and coincidence patterns among the 19 beams. Within the 1.05–1.45 GHz operating bandwidth of the FAST 19 beam receiver, the system achieves a frequency resolution of 122.07 kHz and a time resolution of 270.336 μs. Subsequently, our team detected a series of bursts with a DM of 566 on 2019 August 30 confirming them as FRB 121102. The FRB searching system enables the 19-beam receiver of FAST to detect repeated/one-off pulses/bursts in real time.

The Apertif Radio Transient System (ARTS): Design, commissioning, data release, and detection of the first five fast radio bursts

Fast radio bursts (FRBs) must be powered by uniquely energetic emission mechanisms. This requirement has eliminated a number of possible source types, but several remain. Identifying the physical nature of FRB emitters arguably requires good localisation of more detections, as well as broad-band studies enabled by real-time alerting. In this paper, we present the Apertif Radio Transient System (ARTS), a supercomputing radio-telescope instrument that performs real-time FRB detection and localisation on the Westerbork Synthesis Radio Telescope (WSRT) interferometer. It reaches coherent-addition sensitivity over the entire field of the view of the primary-dish beam. After commissioning results verified that the system performed as planned, we initiated the Apertif FRB survey (ALERT). Over the first 5 weeks we observed at design sensitivity in 2019, we detected five new FRBs, and interferometrically localised each of them to 0.4–10 sq. arcmin. All detections are broad band, very narrow, of the order of 1 ms in duration, and unscattered. Dispersion measures are generally high. Only through the very high time and frequency resolution of ARTS are these hard-to-find FRBs detected, producing an unbiased view of the intrinsic population properties. Most localisation regions are small enough to rule out the presence of associated persistent radio sources. Three FRBs cut through the halos of M31 and M33. We demonstrate that Apertif can localise one-off FRBs with an accuracy that maps magneto-ionic material along well-defined lines of sight. The rate of one every ~7 days ensures a considerable number of new sources are detected for such a study. The combination of the detection rate and localisation accuracy exemplified by the first five ARTS FRBs thus marks a new phase in which a growing number of bursts can be used to probe our Universe.

Detecting cosmic strings with lensed fast radio bursts

Correlated red noise recently reported from pulsar timing observations may be an indication of stochastic gravitational waves emitted by cosmic strings that formed during a primordial phase transition near the grand unification energy scale. Unfortunately, known probes of cosmic strings, namely the cosmic microwave background anisotropies and string lensing of extragalactic galaxies, are not sensitive enough for low dimensionless string tensions of $G\ensuremath{\mu}{c}^{\ensuremath{-}2}={10}^{\ensuremath{-}10}\ensuremath{-}{10}^{\ensuremath{-}7}$ (where the tension $\ensuremath{\mu}$ is the string energy per unit length) that are needed to explain this putative signal. We show that strong gravitational lensing of fast radio bursts (FRBs) by cosmic strings is a potentially unambiguous avenue to probe that range of string tension values. The image pair of string lensing are expected to have identical magnification factor and parity, and have a typical time delay of $\ensuremath{\sim}{10}^{2}(G\text{ }\ensuremath{\mu}\text{ }{c}^{\ensuremath{-}2}/{10}^{\ensuremath{-}8}{)}^{2}\text{ }\text{ }\mathrm{s}$. The unique spectral fingerprint of each FRB, as well as the possibility to detect correlations in the time series of the electric field of the radio waves, will enable verification of the string lensing interpretation. Very-long-baseline interferometry observations can spatially resolve the image pair and provide a lower bound on the string tension based on the image separation. We calculate the FRB lensing rate as a function of the FRB detection number for several different models of the FRB redshift distribution. We find that a survey detecting $\ensuremath{\sim}{10}^{5}$ FRBs, in line with estimates for the detection rate of the forthcoming survey CHORD, can uncover a strong lensing event for a string tension of $G\ensuremath{\mu}\text{ }{c}^{\ensuremath{-}2}\ensuremath{\simeq}{10}^{\ensuremath{-}7}$. Larger FRB surveys, such as Phase 2 of the Square Kilometre Array, have the potential to significantly improve the sensitivity on the string tension to $G\ensuremath{\mu}\text{ }{c}^{\ensuremath{-}2}\ensuremath{\simeq}{10}^{\ensuremath{-}9}$.

Image plane detection of FRB121102 with the MeerKAT radio telescope

ABSTRACT We present the analysis of radio interferometric 2-s images from a MeerKAT observation of the repeating fast radio burst FRB121102 in 2019 September, during which 11 distinct pulses have been previously detected using high time and frequency resolution data cubes. In this work, we detected 6 out of the 11 bursts in the image plane at 1.48 GHz with a minimum peak signal-to-noise ratio (S/N) of 5σ and a fluence detection limit of ∼0.512 Jy ms. These constitute the first detections of a fast radio burst (FRB) or a radio transient using 2-s time-scale images with MeerKAT data. Analysis of the fitted burst properties revealed a weighted average precision of ∼1 arcsec in the localization of the bursts. The accurate knowledge of FRB positions is essential for identifying their host galaxy and understanding their mysterious nature that is still unresolved to this day. We also produced 2-s images at 1.09 GHz but yielded no detection that we attributed to the spectral structure of the pulses that are mostly higher in strength in the upper frequencies. We also explore a new approach to difference image analysis (DIA) to search for transients and find that our technique has the potential to reduce the number of candidates and could be used to automate the detection of FRBs in the image plane for future MeerKAT observations.

Prospects of strongly lensed fast radio bursts: simultaneous measurement of post-Newtonian parameter and Hubble constant

ABSTRACT Strong gravitational lensing effect is a powerful tool to probe cosmological models and gravity theories. Recently, the time-delay cosmography from strong lensing and the stellar kinematics of the deflector, which encode the Hubble constant and the post-Newtonian parameter via two distance ratios reflecting the lensing mass and dynamical mass, respectively, have been proposed to investigate these two parameters simultaneously. Among strong-lensing systems with different sources, strongly lensed fast radio bursts (FRBs) have been proposed as precision probes of the universe since the time-delay ∼ 10 d between images could be measured extremely precisely because of their short duration of a few milliseconds. In this work, we investigate the ability of strongly lensed FRBs on simultaneously estimating these two parameters via simulations. Take the expected FRB detection rate of upcoming facilities and lensing probability into consideration, it is likely to accumulate 10 lensed FRBs in several years and we find that H0 could be determined to an $\sim 1.5{{\,\rm per\,cent}}$ precision and γPPN could be constrained to an $\sim 8.7{{\,\rm per\,cent}}$ precision simultaneously from them. These simultaneous estimations will be helpful for properly reflecting the possible correlation between these two fundamental parameters.

Constraining bright optical counterparts of fast radio bursts

Context. Fast radio bursts (FRBs) are extremely energetic pulses of millisecond duration and unknown origin. To understand the phenomenon that emits these pulses, targeted and un-targeted searches have been performed for multiwavelength counterparts, including the optical. Aims. The objective of this work is to search for optical transients at the positions of eight well-localized (&lt; 1″) FRBs after the arrival of the burst on different timescales (typically at one day, several months, and one year after FRB detection). We then compare this with known optical light curves to constrain progenitor models. Methods. We used the Las Cumbres Observatory Global Telescope (LCOGT) network to promptly take images with its network of 23 telescopes working around the world. We used a template subtraction technique to analyze all the images collected at differing epochs. We have divided the difference images into two groups: In one group we use the image of the last epoch as a template, and in the other group we use the image of the first epoch as a template. We then searched for optical transients at the localizations of the FRBs in the template subtracted images. Results. We have found no optical transients and have therefore set limiting magnitudes to the optical counterparts. Typical limits in apparent and absolute magnitudes for our LCOGT data are ∼22 and −19 mag in the r band, respectively. We have compared our limiting magnitudes with light curves of super-luminous supernovae (SLSNe), Type Ia supernovae (SNe Ia), supernovae associated with gamma-ray bursts (GRB-SNe), a kilonova, and tidal disruption events (TDEs). Conclusions. Assuming that the FRB emission coincides with the time of explosion of these transients, we rule out associations with SLSNe (at the ∼99.9% confidence level) and the brightest subtypes of SNe Ia, GRB-SNe, and TDEs (at a similar confidence level). However, we cannot exclude scenarios where FRBs are directly associated with the faintest of these subtypes or with kilonovae.

Model-independent Estimation of H 0 and Ω K from Strongly Lensed Fast Radio Bursts

Abstract Model-independent estimation of H 0 and Ω K can provide clues about the origin of the intractable Hubble constant tension and the current cosmic-curvature crisis. Strongly lensed fast radio bursts (FRBs) have been proposed as precision probes of the universe since the time delay ∼  (10 days) between images could be precisely measured due to short durations ∼  ( ms ) of this kind of bright radio pulses. Here, on the basis of the distance sum rule, we investigate the capacity of model-independently estimating these two parameters from time-delay distances of strongly lensed FRBs and luminosity distances of the upcoming Wide Field InfraRed Survey Telescope (WFIRST) type Ia supernovae observations. Considering the expected FRB detection rate of upcoming facilities, we find that H 0 could be determined to a ∼1% precision and Ω K could be constrained to ∼0.1 simultaneously from 10 lensed FRBs. These estimations, which are independent of the energy contents of the universe and validity of Einstein’s equation on cosmological scales, will be complementary to popular probes and of great importance for clarifying the current crises of cosmology.

Earth-mass primordial black hole mergers as sources for nonrepeating fast radio bursts

Fast radio bursts (FRBs) are mysterious astronomical radio transients with extremely short intrinsic duration. Until now, the physical origins of them still remain elusive especially for the non-repeating FRBs. Strongly inspired by recent progress on possible evidence of Earth-mass primordial black holes, we revisit the model of Earth-mass primordial black holes mergers as sources for non-repeating FRBs. Under the null hypothesis that the observed non-repeating FRBs are originated from the mergers of Earth-mass primordial black holes, we analyzed four independent samples of non-repeating FRBs to study the model parameters i.e. the typical charge value $q_{\rm{c}}$ and the power index $\alpha$ of the charge distribution function of the primordial black hole population $\phi(q) \propto (q/q_{\rm{c}})^{-\alpha}$ which describe how the charge was distributed in the population. $q$ is the charge of the hole in the unit of $\sqrt{G} M$, where $M$ is the mass of the hole. It turns out that this model can explain the observed data well. {Assuming the monochromatic mass spectrum for primordial black holes}, we get the average value of typical charge $\bar{q}_{\rm{c}}/10^{-5}=1.59^{+0.08}_{-0.18}$ and the power index $\bar{\alpha}=4.53^{+0.21}_{-0.14}$ by combining the fitting results given by four non-repeating FRB samples. The event rate of the non-repeating FRBs can be explained in the context of this model, if the abundance of the primordial black hole populations with charge $q \gtrsim 10^{-6}$ is larger than $10^{-5}$ which is far below the upper limit given by current observations for the abundance of Earth-mass primordial black holes. In the future, simultaneous detection of FRBs and high frequency gravitational waves produced by mergers of Earth-mass primordial black holes may directly confirm or deny this model.

Constraining HeII reionization detection uncertainties via fast radio bursts

The rate of detection of Fast Radio Bursts (FRBs) in recent years has increased rapidly, and getting samples of sizes O(102) to O(103) is likely possible. FRBs exhibit short radio bursts in order of milliseconds at frequencies ∼1 GHz. The high dispersion measures (DM) of FRBs suggest it’s extragalactic origin, which allows probing the electron density in the intergalactic medium (IGM). In this project, we explored the possibility of identifying the epoch of helium II (HeII) reionization, via the observations of early FRBs in the range of z=[3,4]. We constrained the HeII reionization with a different number of observed early FRBs and associated redshift measurement errors to them. We built a model of FRB DMs following the HeII reionization model, while taking into account the density fluctuation in large scale structure, host galaxy interstellar medium, and local environment of FRB contribution. Following the model, FRB DMs with redshift in range of z=[3,4] is generated. We then fit these data to the ideal IGM dispersion measure model, checking the constraint tightness of the HeII reionization epoch. We show that detection of 100 FRB gives an uncertainty of σ(zr,fit)∼0.5 without considering additional redshift noise, which increases to σ(zr,fit)∼0.6 when 20% of redshift noise is added. Detection of 1000 candidate gives an uncertainty of σ(zr,fit)∼0.1 and increases to σ(zr,fit)∼0.15 when 20% of redshift noise is added.

An Analysis Pipeline for CHIME/FRB Full-array Baseband Data

Abstract The Canadian Hydrogen Intensity Mapping Experiment (CHIME) has become a leading facility for detecting fast radio bursts (FRBs) through the CHIME/FRB backend. CHIME/FRB searches for fast transients in polarization-summed intensity data streams that have 24 kHz spectral and 1 ms temporal resolution. The intensity beams are pointed to predetermined locations in the sky. A triggered baseband system records the coherent electric field measured by each antenna in the CHIME array at the time of FRB detections. Here we describe the analysis techniques and automated pipeline developed to process these full-array baseband data recordings. Whereas the real-time FRB detection pipeline has a localization limit of several arcminutes, offline analysis of baseband data yields source localizations with subarcminute precision, as characterized by using a sample of pulsars and one repeating FRB with known positions. The baseband pipeline also enables resolving temporal substructure on a microsecond scale and the study of polarization including detections of Faraday rotation.

Multiwavelength Observations of Fast Radio Bursts

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.

Fast radio burst detection in the presence of coloured noise

ABSTRACT In this paper, we investigate the impact of correlated noise on fast radio burst (FRB) searching. We found that (1) the correlated noise significantly increases the false alarm probability; (2) the signal-to-noise ratios (S/N) of the false positives become higher; (3) the correlated noise also affects the pulse width distribution of false positives, and there will be more false positives with wider pulse width. We use 55-h observation for M82 galaxy carried out at Nanshan 26m radio telescope to demonstrate the application of the correlated noise modelling. The number of candidates and parameter distribution of the false positives can be reproduced with the modelling of correlated noise. We will also discuss a low S/N candidate detected in the observation, for which we demonstrate the method to evaluate the false alarm probability in the presence of correlated noise. Possible origins of the candidate are discussed, where two possible pictures, an M82-harboured giant pulse and a cosmological FRB, are both compatible with the observation.

The First Fast Radio Burst Detected with VLITE-Fast

Abstract The VLITE-Fast experiment combines the wide-field-of-view of single dish antennas operating at low frequency with the high angular resolution furnished by the 3–30 km baselines of the VLA, making it ideal for the detection and precise localization of radio transients. We describe the VLITE-Fast experiment, its capabilities, and operational status, and we briefly overview its main science case, the detection of fast radio bursts (FRBs) and determination of their host galaxies. We report on commissioning observations in an incoherent mode prohibiting precise localization. These include discovery of FRB 20200405A, detected during early science operations at dispersion measure (DM) = 212.3 pc cm−3, strongly in excess of the Galactic DM along the line of sight.

A Southern-Hemisphere all-sky radio transient monitor for SKA-Low prototype stations

AbstractWe present the first Southern-Hemisphere all-sky imager and radio-transient monitoring system implemented on two prototype stations of the low-frequency component of the Square Kilometre Array (SKA-Low). Since its deployment, the system has been used for real-time monitoring of the recorded commissioning data. Additionally, a transient searching algorithm has been executed on the resulting all-sky images. It uses a difference imaging technique to enable identification of a wide variety of transient classes, ranging from human-made radio-frequency interference to genuine astrophysical events. Observations at the frequency 159.375 MHz and higher in a single coarse channel ($\approx$0.926 MHz) were made with 2 s time resolution, and multiple nights were analysed generating thousands of images. Despite having modest sensitivity ($\sim$few Jy beam–1), using a single coarse channel and 2-s imaging, the system was able to detect multiple bright transients from PSR B0950+08, proving that it can be used to detect bright transients of an astrophysical origin. The unusual, extreme activity of the pulsar PSR B0950+08 (maximum flux density$\sim$155 Jy beam–1) was initially detected in a ‘blind’ search in the 2020 April 10/11 data and later assigned to this specific pulsar. The limitations of our data, however, prevent us from making firm conclusions of the effect being due to a combination of refractive and diffractive scintillation or intrinsic emission mechanisms. The system can routinely collect data over many days without interruptions; the large amount of recorded data at 159.375 and 229.6875 MHz allowed us to determine a preliminary transient surface density upper limit of$1.32 \times 10^{-9} \text{deg}^{-2}$for a timescale and limiting flux density of 2 s and 42 Jy, respectively. In the future, we plan to extend the observing bandwidth to tens of MHz and improve time resolution to tens of milliseconds in order to increase the sensitivity and enable detections of fast radio bursts below 300 MHz.