Mining the time axis with TRON - III. Discovery of a nulling pulsar towards the SMC with MeerKAT

Abstract

We report on the discovery of a nulling pulsar, PSR J0052−7551, in archival MeerKAT L-band observations of the Small Magellanic Cloud (SMC). The discovery was made using the image-plane transient detection pipeline, TRON, which creates a residual image for each time sample and uses a heuristic pruning strategy to identify promising candidates in the resulting temporal image cube. The TRON pipeline triggered on the approximately minute timescale variability associated with the nulling behaviour of a canonical pulsar. Follow-up MeerKAT UHF-band beamformer observations revealed a pulsar with a spin period of 0.55 s and a measured period derivative of 6.1(6)×10⁻¹⁷s·s⁻¹. The source is seen in projection toward the periphery of the SMC, and has a dispersion measure value of 29.24(2) pc·cm⁻³, which is on the order of the expected Milky Way contribution along the line of sight. We use a Gaussian Mixture Model to fit the nulling behaviour which yielded a nulling fraction of ∼ 32%. We find that the null lengths are consistent with an exponential distribution indicating a stochastic process. Additionally, power spectra of the UHF visibility data reveal an unexplained quasi-periodic feature at ~5−7 s that cannot be attributed to the source itself, RFI, or standard instrumental effects. Following on from previous image-plane detections of pulsars by the TRON approach, which relied on either scintillation or eclipsing behaviour, this is the first detection triggered by nulling. This discovery confirms TRON's sensitivity to a wide range of astrophysical phenomena of medium timescale duration.

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BibTeX RIS

BibTeX

@misc{blecher2026mining,
  title = {{Mining the time axis with TRON - III. Discovery of a nulling pulsar towards the SMC with MeerKAT}},
  author = {T Blecher and M Geyer and O.M Smirnov and A Coelen and I Heywood and I Pelisoli and A.K Hughes and J.S Bright and V Prayag and T Myburgh and C Tasse and B Hugo and J.S Kenyon and H.L Bester and S.J Perkins and J Dawson and V.G Samboco and A.J.T Ramaila and B Ngcebetsha and I Sihlangu and C Choza and V.S Dhillon and N. Castro Segura and J Mccormac},
  howpublished = {HAL},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.07528},
  eprint = {2609.07528},
  archivePrefix = {arXiv},
  url = {https://hal.science/hal-05770572v1},
  note = {CC BY 4.0},
}

RIS

TY  - UNPB
TI  - Mining the time axis with TRON - III. Discovery of a nulling pulsar towards the SMC with MeerKAT
AU  - T Blecher
AU  - M Geyer
AU  - O.M Smirnov
AU  - A Coelen
AU  - I Heywood
AU  - I Pelisoli
AU  - A.K Hughes
AU  - J.S Bright
AU  - V Prayag
AU  - T Myburgh
AU  - C Tasse
AU  - B Hugo
AU  - J.S Kenyon
AU  - H.L Bester
AU  - S.J Perkins
AU  - J Dawson
AU  - V.G Samboco
AU  - A.J.T Ramaila
AU  - B Ngcebetsha
AU  - I Sihlangu
AU  - C Choza
AU  - V.S Dhillon
AU  - N. Castro Segura
AU  - J Mccormac
PY  - 2026
DA  - 2026/09/07
PB  - HAL
DO  - 10.48550/arxiv.2609.07528
UR  - https://hal.science/hal-05770572v1
AB  - We report on the discovery of a nulling pulsar, PSR J0052−7551, in archival MeerKAT L-band observations of the Small Magellanic Cloud (SMC). The discovery was made using the image-plane transient detection pipeline, TRON, which creates a residual image for each time sample and uses a heuristic pruning strategy to identify promising candidates in the resulting temporal image cube. The TRON pipeline triggered on the approximately minute timescale variability associated with the nulling behaviour of a canonical pulsar. Follow-up MeerKAT UHF-band beamformer observations revealed a pulsar with a spin period of 0.55 s and a measured period derivative of 6.1(6)×10^−17s·s^−1. The source is seen in projection toward the periphery of the SMC, and has a dispersion measure value of 29.24(2) pc·cm^−3, which is on the order of the expected Milky Way contribution along the line of sight. We use a Gaussian Mixture Model to fit the nulling behaviour which yielded a nulling fraction of ∼ 32%. We find that the null lengths are consistent with an exponential distribution indicating a stochastic process. Additionally, power spectra of the UHF visibility data reveal an unexplained quasi-periodic feature at ~5−7 s that cannot be attributed to the source itself, RFI, or standard instrumental effects. Following on from previous image-plane detections of pulsars by the TRON approach, which relied on either scintillation or eclipsing behaviour, this is the first detection triggered by nulling. This discovery confirms TRON's sensitivity to a wide range of astrophysical phenomena of medium timescale duration.
ER  -

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