TRAPUM discovery of 13 new pulsars in NGC 1851 using MeerKAT^⋆

¹ INAF – Osservatorio Astronomico di Cagliari, Via della Scienza 5, 09047 Selargius, CA, Italy
e-mail: alessandro.ridolfi@inaf.it
² Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany
e-mail: pfreire@mpifr-bonn.mpg.de
³ National Radio Astronomy Observatory, 520 Edgemont Rd., Charlottesville, VA 22903, USA
⁴ South African Radio Astronomy Observatory (SARAO), 2 Fir Street, Black River Park, Observatory, Cape Town 7925, South Africa
⁵ Jodrell Bank Centre for Astrophysics, Department of Physics and Astronomy, The University of Manchester, Manchester M13 9PL, UK
⁶ Università di Cagliari, Dipartimento di Fisica, S.P. Monserrato-Sestu Km 0,700, 09042 Monserrato, CA, Italy
⁷ Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut), 30167 Hannover, Germany
⁸ Centre for Astrophysics and Supercomputing, Swinburne University of Technology, PO Box 218 Hawthorn, VIC 3122, Australia
⁹ ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav), Australia
¹⁰ School of Physics, Trinity College Dublin, College Green, Dublin 2, Ireland
¹¹ LPC2E – Université d’Orléans/CNRS, 45071 Orléans Cedex 2, France
¹² Station de Radioastronomie de Nançay, Observatoire de Paris, PSL Research University, CNRS, Univ. Orléans, OSUC, 18330 Nançay, France
¹³ Fakultät für Physik, Universität Bielefeld, Postfach 100131, 33501 Bielefeld, Germany
¹⁴ Department of Physics and Electronics, Rhodes University, PO Box 94 Grahamstown 6140, South Africa
¹⁵ SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield SK11 9FT, UK
¹⁶ Department of Physics and Astronomy, University of the Western Cape, Bellville, Cape Town 7535, South Africa

Received: 25 December 2021
Accepted: 23 March 2022

Abstract

We report the discovery of 13 new pulsars in the globular cluster NGC 1851 by the TRAPUM Large Survey Project using the MeerKAT radio telescope. The discoveries consist of six isolated millisecond pulsars (MSPs) and seven binary pulsars, of which six are MSPs and one is mildly recycled. For all the pulsars, we present the basic kinematic, astrometric, and orbital parameters, where applicable, as well as their polarimetric properties, when these are measurable. Two of the binary MSPs (PSR J0514−4002D and PSR J0514−4002E) are in wide and extremely eccentric (e > 0.7) orbits with a heavy white dwarf and a neutron star as their companion, respectively. With these discoveries, NGC 1851 is now tied with M28 as the cluster with the third largest number of known pulsars (14). Its pulsar population shows remarkable similarities with that of M28, Terzan 5, and other clusters with comparable structural parameters. The newly found pulsars are all located in the innermost regions of NGC 1851 and will likely enable, among other things, detailed studies of the cluster structure and dynamics.