A targeted radio pulsar survey of redback candidates with MeerKAT

authored by

T. Thongmeearkom, C. J. Clark, R. P. Breton, M. Burgay, L. Nieder, P. C.C. Freire, E. D. Barr, B. W. Stappers, S. M. Ransom, S. Buchner, F. Calore, D. J. Champion, I. Cognard, J. M. Grießmeier, M. Kramer, L. Levin, P. V. Padmanabh, A. Possenti, A. Ridolfi, V. Venkatraman Krishnan, L. Vleeschower

Abstract

Redbacks are millisecond pulsar binaries with low-mass, irradiated companions. These systems have a rich phenomenology that can be used to probe binary evolution models, pulsar wind physics, and the neutron star mass distribution. A number of high-confidence redback candidates have been identified through searches for variable optical and X-ray sources within the localization regions of unidentified but pulsar-like Fermi-LAT gamma-ray sources. However, these candidates remain unconfirmed until pulsations are detected. As part of the TRAPUM project, we searched for radio pulsations from six of these redback candidates with MeerKAT. We discovered three new radio millisecond pulsars, PSRs J0838−2827, J0955−3947, and J2333−5526, confirming their redback nature. PSR J0838−2827 remained undetected for 2 yr after our discovery despite repeated observations, likely due to evaporated material absorbing the radio emission for long periods of time. While, to our knowledge, this system has not undergone a transition to an accreting state, the disappearance, likely caused by extreme eclipses, illustrates the transient nature of spider pulsars and the heavy selection bias in uncovering their radio population. Radio timing enabled the detection of gamma-ray pulsations from all three pulsars, from which we obtained 15-yr timing solutions. All of these sources exhibit complex orbital period variations consistent with gravitational quadrupole moment variations in the companion stars. These timing solutions also constrain the binary mass ratios, allowing us to narrow down the pulsar masses.

Organisation(s)

Institute of Gravitation Physics

External Organisation(s)

University of Manchester
National Astronomical Research Institute of Thailand
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
Istituto Nazionale di Astrofisica (INAF)
Max Planck Institute for Radio Astronomy (MPIfR)
South African Radio Astronomy Observatory (SARAO)
LAPTH Laboratoire d'Annecy-Le-Vieux de Physique Theorique
Universite d'Orleans
PSL Research University
University of Wisconsin Milwaukee
National Radio Astronomy Observatory, Charlottesville
Centre national de la recherche scientifique (CNRS)

Type

Article

Journal

Monthly Notices of the Royal Astronomical Society

Volume

530

Pages

4676-4694

No. of pages

19

ISSN

0035-8711

Publication date

26.03.2024

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Astronomy and Astrophysics, Space and Planetary Science

Electronic version(s)

https://doi.org/10.48550/arXiv.2403.09553 (Access: Open)
https://doi.org/10.1093/mnras/stae787 (Access: Open)