A MeerKAT view of the pulsars in the globular cluster NGC 6522

¹ Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
² INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, 09047 Selargius (CA), Italy
e-mail: federico.abbate@inaf.it
³ Dipartimento di Fisica “G. Occhialini”, Università degli Studi di Milano-Bicocca, Piazza della Scienza 3, 20126 Milano, Italy
⁴ Max Planck Institute for Gravitational Physics (Albert Einstein Institute), 30167 Hannover, Germany
⁵ Leibniz Universität Hannover, 30167 Hannover, Germany
⁶ South African Radio Astronomy Observatory, 2 Fir Street, Cape Town 7925, South Africa
⁷ National Astronomical Observatories, Chinese Academy of Sciences, A20 Datun Road, Chaoyang District, Beijing 100101, PR China
⁸ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
⁹ National Radio Astronomy Observatory, 520 Edgemont Rd., Charlottesville, VA 22903, USA

Received: 14 August 2023
Accepted: 3 October 2023

Abstract

We present the results of observations aimed at discovering and studying pulsars in the core-collapsed globular cluster (GC) NGC 6522 performed by the MeerTIME and TRAPUM Large Survey Project with the MeerKAT telescope. We have discovered two new isolated pulsars bringing the total number of known pulsars in the cluster to six. PSR J1803−3002E is a mildly recycled pulsar with a spin period of 17.9 ms, while pulsar PSR J1803−3002F is a slow pulsar with a spin period of 148.1 ms. The presence of isolated and slow pulsars is expected in NGC 6522, and confirms the predictions of previous theories for clusters at this stage in evolution. We further present a tentative timing solution for the millisecond pulsar (MSP) PSR J1803−3002C combining older observations taken with the Parkes 64 m radio telescope, Murriyang. This solution implies a relatively young characteristic age of the pulsar in contrast with the old age of the GC. The presence of a slow pulsar and an apparently young MSP, both rare in GCs, suggests that their formation might be linked to the evolutionary stage of the cluster.