EXTraS discovery of an 1.2-s X-ray pulsar in M 31

Esposito P, Israel GL, Belfiore A, Novara G, Sidoli L, Castillo GAR, De Luca A, Tiengo A, Haberl F, Salvaterra R, Read AM, Salvetti D, Sandrelli S, Marelli M, Wilms J, D'Agostino D (2016)


Publication Status: Published

Publication Type: Journal article, Original article

Publication year: 2016

Journal

Publisher: Oxford University Press

Book Volume: 457

Pages Range: L5-L9

Journal Issue: 1

DOI: 10.1093/mnrasl/slv194

Abstract

During a search for coherent signals in the X-ray archival data of XMM-Newton, we discovered a modulation at 1.2 s in 3XMMJ004301.4+413017 (3X J0043), a source lying in the direction of an external arm ofM31. This short period indicates a neutron star (NS). Between 2000 and 2013, the position of 3X J0043 was imaged by public XMM-Newton observations 35 times. The analysis of these data allowed us to detect an orbital modulation at 1.27 d and study the long-term properties of the source. The emission of the pulsar was rather hard (most spectra are described by a power law withΓ <1) and, assuming the distance to M 31, the 0.3-10 keV luminosity was variable, from ~3 × 10 to 2 × 10 erg s. The analysis of optical data shows that, while 3X J0043 is likely associated to a globular cluster in M 31, a counterpart with V ≥ 22 outside the cluster cannot be excluded. Considering our findings, there are two main viable scenarios for 3X J0043: a peculiar low-mass X-ray binary, similar to 4U 1822-37 or 4U 1626-67, or an intermediate-mass X-ray binary resembling Her X-1. Regardless of the exact nature of the system, 3X J0043 is the first accreting NS in M 31 in which the spin period has been detected.

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How to cite

APA:

Esposito, P., Israel, G.L., Belfiore, A., Novara, G., Sidoli, L., Castillo, G.A.R.,... D'Agostino, D. (2016). EXTraS discovery of an 1.2-s X-ray pulsar in M 31. Monthly Notices of the Royal Astronomical Society: Letters, 457(1), L5-L9. https://doi.org/10.1093/mnrasl/slv194

MLA:

Esposito, Paolo, et al. "EXTraS discovery of an 1.2-s X-ray pulsar in M 31." Monthly Notices of the Royal Astronomical Society: Letters 457.1 (2016): L5-L9.

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