The first MeerKAT S-band globular cluster pulsar survey

Authors:
  • RNRouhin Nag
    Rouhin Nag
  • MBMarta Burgay
    Marta Burgay
  • ARAlessandro Ridolfi
    Alessandro Ridolfi
  • FAFederico Abbate
    Federico Abbate
  • APAndrea Possenti
    Andrea Possenti
  • PFPaulo C. C. Freire
    Paulo C. C. Freire
  • SRScott M. Ransom
    Scott M. Ransom
  • MBMiquel Colom i Bernadich
    Miquel Colom i Bernadich
  • MKMichael Kramer
    Michael Kramer
  • BSBenjamin W. Stappers
    Benjamin W. Stappers
  • EBEwan D. Barr
    Ewan D. Barr
  • RBRene P. Breton
    Rene P. Breton
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Abstract
Globular clusters are efficient factories of recycled pulsars, but searches toward high-dispersion-measure (DM) clusters can be strongly limited near 1 GHz by dispersive smearing and interstellar scattering. We present the first MeerKAT S-band (nu ~ 2.4 GHz) pulsar survey of 14 globular clusters. High time- and frequency-resolution observations were searched using segmented acceleration and jerk techniques, followed by candidate folding and targeted folding with available timing ephemerides. We re-detected 39 known pulsars and discovered four new millisecond pulsars in Glimpse-C01: J1848-0129C, D, E, and F. Multi-epoch follow-up enabled preliminary Keplerian orbital fits for J1848-0129C and J1848-0129D. J1848-0129C is an eclipsing MSP in a ~5 d orbit, placing it among long-period eclipsing systems known as huntsman binaries, while J1848-0129D is in a ~3.4 d nearly circular orbit with a massive white-dwarf companion of about 1 solar mass. Two Glimpse-C01 pulsars show large DM offsets from the cluster average. Comparison with other Galactic globular clusters indicates that intracluster DM spreads tend to increase with foreground DM, implying that narrow DM search windows may be sub-optimal for high-DM clusters. From detections and non-detections, we infer a practical single-epoch MeerKAT S-band tied-array detectability scale of about 10-20 microJy. These results demonstrate the value of high-frequency searches for pulsars in strongly dispersed and scattered cluster environments.