Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1

Piga, Viviana; Burgay, Marta; Possenti, Andrea; Ridolfi, Alessandro; Pilia, Maura; Rea, Nanda; Perna, Rosalba; Colpi, Monica; Israel, Gianluca

doi:10.3390/universe10070274

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Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1

by

Viviana Piga

^1,2,*,

Marta Burgay

^1,*

,

Andrea Possenti

¹,

Alessandro Ridolfi

¹,

Maura Pilia

¹

,

Nanda Rea

^3,4,

Rosalba Perna

^5,6

,

Monica Colpi

^7,8 and

Gianluca Israel

⁹

¹

INAF—Osservatorio Astronomico di Cagliari, Via della Scienza 5, I-09047 Selargius, Italy

²

Dipartimento di Matematica e Informatica, Università di Cagliari, Via Ospedale 72, 09124 Cagliari, Italy

³

Institute of Space Sciences (ICE, CSIC), Carrer de Can Magrans, Cerdanyola del Vallès, 08193 Barcelona, Spain

⁴

Institut d’Estudis Espacials de Catalunya (IEEC), Carrer Gran Capita 2–4, 08034 Barcelona, Spain

⁵

Department of Physics and Astronomy, Stony Brook University, Stony Brook, NY 11794, USA

⁶

Center for Computational Astrophysics, Flatiron Institute, New York, NY 10010, USA

⁷

Dipartimento di Fisica, Università di Milano—Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy

⁸

Instituto Nazionale di Fisica Nucleare (INFN), Sezione di Milano Bicocca, Milano—Bicocca, Piazza della Scienza 3, I-20126 Milano, Italy

⁹

INAF—Osservatorio Astronomico di Roma, Via Frascati 33, I-00078 Monte Porzio Catone, Italy

^*

Authors to whom correspondence should be addressed.

Universe 2024, 10(7), 274; https://doi.org/10.3390/universe10070274

Submission received: 27 April 2024 / Revised: 14 June 2024 / Accepted: 18 June 2024 / Published: 25 June 2024

(This article belongs to the Special Issue New Insights in Fast Radio Bursts)

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Abstract

We report the discovery of PSR J1646−4545, a 431 ms isolated pulsar, in the direction of the young massive cluster Westerlund 1. The pulsar was found in data taken between the years 2005 and 2010 with the “Murriyang” Parkes radio telescope in Australia. Thanks to the numerous detections of the pulsar, we were able to derive a phase-connected timing solution spanning the whole data set. This allowed us to precisely locate the pulsar at the border of the cluster and to measure its spin-down rate. The latter implies a characteristic age of ∼25 Myr, about twice as large as the estimated age of Westerlund 1. The age of PSR J1646−4545, together with its dispersion measure of ∼1029 pc cm

^{- 3}

, more than twice the value predicted by the two main galactic electron density models for Westerlund 1, makes the association of the pulsar with the cluster highly unlikely. We also report on ramifications from the presence of a magnetar in Westerlund 1 and the apparent lack of ordinary radio pulsars.

Keywords: Westerlund 1; pulsar; PSR J1646-4545

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MDPI and ACS Style

Piga, V.; Burgay, M.; Possenti, A.; Ridolfi, A.; Pilia, M.; Rea, N.; Perna, R.; Colpi, M.; Israel, G. Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1. Universe 2024, 10, 274. https://doi.org/10.3390/universe10070274

AMA Style

Piga V, Burgay M, Possenti A, Ridolfi A, Pilia M, Rea N, Perna R, Colpi M, Israel G. Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1. Universe. 2024; 10(7):274. https://doi.org/10.3390/universe10070274

Chicago/Turabian Style

Piga, Viviana, Marta Burgay, Andrea Possenti, Alessandro Ridolfi, Maura Pilia, Nanda Rea, Rosalba Perna, Monica Colpi, and Gianluca Israel. 2024. "Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1" Universe 10, no. 7: 274. https://doi.org/10.3390/universe10070274

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

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Serendipitous Discovery of a 431 ms Pulsar in the Background of Westerlund 1

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