Wide field beamformed observation with MeerKAT

Chen, Weiwei; Barr, Ewan; Karuppusamy, Ramesh; Kramer, Michael; Stappers, Benjamin

doi:10.48550/arxiv.2110.01667

Cited by 6 publications

(16 citation statements)

References 42 publications

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“…Together these machines are able to synthesize and record of order 500 coherent beams for use in pulsar and fast transient searching. Using all of the available antennas it is possible to cover, with a large number of small tiedarray beams, an area as large as 1 − 4 arcmin in radius depending on the configuration (Chen et al 2021). This is enough to extend up to more than twice the reported half-light radius of the GC of ∼ 1 arcmin (Baumgardt & Hilker 2018).…”

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confidence: 99%

Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT

Abbate

Ridolfi

Barr

et al. 2022

Monthly Notices of the Royal Astronomical Society

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We report 4 new pulsars discovered in the core-collapsed globular cluster (GC) NGC 6624 by the TRAPUM Large Survey Project with the MeerKAT telescope. All of the new pulsars found are isolated. PSR J1823−3021I and PSR J1823−3021K are millisecond pulsars with period of respectively 4.319 ms and 2.768 ms. PSR J1823−3021J is mildly recycled with a period of 20.899 ms, and PSR J1823−3022 is a long period pulsar with a period of 2.497 s. The pulsars J1823−3021I, J1823−3021J, and J1823−3021K have position and dispersion measure (DM) compatible with being members of the GC and are therefore associated with NGC 6624. Pulsar J1823−3022 is the only pulsar bright enough to be re-detected in archival observations of the cluster. This allowed the determination of a timing solution that spans over two decades. It is not possible at the moment to claim the association of pulsar J1823−3022 with the GC given the long period and large offset in position (∼3 arcminutes) and DM (with a fractional difference of 11 percent compared the average of the pulsars in NGC 6624). The discoveries made use of the beamforming capability of the TRAPUM backend to generate multiple beams in the same field of view which allows sensitive searches to be performed over a few half-light radii from the cluster center and can simultaneously localise the discoveries. The discoveries reflect the properties expected for pulsars in core-collapsed GCs.

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confidence: 99%

Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT

Abbate

Ridolfi

Barr

et al. 2022

Monthly Notices of the Royal Astronomical Society

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“…), while the single pulse search algorithm is delineated in Malenta et al (2020) and a preliminary overview is given by Rajwade et al (2021). In regular operation, the on-site Filterbank BeamFormer User Supplied Equipment (FBFUSE) cluster, developed by collaborators at the Max-Planck Institut für Radioastronomie (Chen et al 2021), uses channelised complex voltage data from the MeerKAT UHF-band (544 -1088 MHz) or L-band receivers (856 -1712 MHz) to form up to 768 coherent beams (CBs) on the sky, typically using about 40 dishes in the dense core region of the MeerKAT telescope array. An incoherent beam (IB) is also formed using the sum of the data from up to 64 MeerKAT antennas.…”

Section: Observations and Data Processingmentioning

confidence: 99%

“…This is determined by an ellipse fit to a model of the CBs' PSF at ∼1284 MHz. For more details on how this is achieved see Chen et al (2021). 5 https://pulsars.org.au/public/J0931-1902 sources.…”

Section: Observations and Data Processingmentioning

confidence: 99%

“…They were also extremely variable, with pulses in the nearest beam to the source position registering S/N values 18 ranging in S/N from 8 to 61. In order to correct the S/N values for the source's position within the CB, we simulated the CB PSFs using the beam synthesis simulation code MOSAIC (Chen et al 2021) and estimated the fractional sensitivity of the beam at the position of PSR J1901+0254; we then divided the S/N values by this fraction. We also applied a small correction for the CBs' position within the MeerKAT primary beam.…”

Section: Mtp0008/psr J1901+0254mentioning

confidence: 99%

“…Further details about this project can be found in Sanidas et al (2018), Jankowski et al (2020), Malenta et al (2020), Rajwade et al (2021), and a forthcoming system description paper (Stappers et al in prep.). MeerTRAP operates on a commensal basis, meaning that during any given MeerKAT observation it can receive the digitised and channelised data from hundreds of coherent beams formed on the sky using a custom beamformer (Chen et al 2021), and search those beams in real time for single pulses. Because of the limiting cost of data storage, all these data can not be stored permanently, and the single pulse search must take place in real time.…”

Section: Introductionmentioning

confidence: 99%

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MeerTRAP: Twelve Galactic fast transients detected in a real-time, commensal MeerKAT survey

Bezuidenhout,

Barr,

Caleb

et al. 2022

Preprint

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MeerTRAP is a real-time untargeted search project using the MeerKAT telescope to find single pulses from fast radio transients and pulsars. It is performed commensally with the MeerKAT large survey projects (LSPs), using data from up to 64 of MeerKAT's 13.96 m dishes to form hundreds of coherent beams on sky, each of which is processed in real time to search for millisecondduration pulses. We present the first twelve Galactic sources discovered by MeerTRAP, with DMs in the range of 33-381 pc cm −3 . One source may be Galactic or extragalactic depending on the Galactic electron density model assumed. Follow-up observations performed with the MeerKAT, Lovell, and Parkes radio telescopes have detected repeat pulses from seven of the twelve sources. Pulse periods have been determined for four sources. Another four sources could be localised to the arcsecond-level using a novel implementation of the tied-array beam localisation method.

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Discovery of a radio-emitting neutron star with an ultra-long spin period of 76 s

et al. 2022

Self Cite

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The radio-emitting neutron star population encompasses objects with spin periods ranging from milliseconds to tens of seconds. As they age and spin more slowly, their radio emission is expected to cease. We present the discovery of an ultra-long period radio-emitting neutron star, PSR J0901−4046 , with spin properties distinct from the known spin and magnetic-decay powered neutron stars. With a spinperiod of 75.88 s, a characteristic age of 5.3 Myr, and a narrow pulse duty-cycle, it is uncertain how radio emission is generated and challenges our current understanding of how these systems evolve. The radio emission has unique spectro-temporal properties such as quasi-periodicity and partial nulling that provide important clues to the emission mechanism. Detecting similar sources is observationally challenging, which implies a larger undetected population. Our discovery establishes the existence of ultra-long period neutron stars, suggesting a possible connection to the evolution of highly magnetized neutron stars, ultra-long period magnetars, and fast radio bursts.

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Wide field beamformed observation with MeerKAT

Cited by 6 publications

References 42 publications

Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT

Four pulsar discoveries in NGC 6624 by TRAPUM using MeerKAT

MeerTRAP: Twelve Galactic fast transients detected in a real-time, commensal MeerKAT survey

Discovery of a radio-emitting neutron star with an ultra-long spin period of 76 s

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