XMM-Newton spectral and timing analysis of the faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307

N.A. Webb (1) , J.F. Olive (1) , D. Barret (1) , M. Kramer (2) , Ismaël Cognard (3) , O. Lomer (1)

1 CESR - Centre d'étude spatiale des rayonnements
2 Jodrell Bank Observatory
3 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace

We present XMM-Newton MOS imaging and PN timing data of the faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307. We find 46 sources in the MOS field of view of PSR J0751+1807 searching down to an unabsorbed flux limit of 3 × 10 −15 ergs cm −2 s −1 (0.2-10.0 keV). We present, for the first time, the X-ray spectra of these two faint millisecond pulsars. We find that a power law model best fits the spectrum of PSR J0751+1807, Γ = 1.59 ± 0.20, with an unabsorbed flux of 4.4 × 10 −14 ergs cm −2 s −1 (0.2-10.0 keV). A power law is also a good description of the spectrum of PSR J1012+5307, Γ = 1.78 ± 0.36, with an unabsorbed flux of 1.2 × 10 −13 ergs cm −2 s −1 (0.2-10.0 keV). However, a blackbody model cannot be excluded as the best fit to this data. We present some evidence to suggest that both of these millisecond pulsars show pulsations in this X-ray band. We find some evidence for a single broad X-ray pulse for PSR J0751+1807 and we discuss the possibility that there are two pulses per spin period for PSR J1012+5307.

Keywords: X-rays: stars; stars: pulsars: individual: PSR J0751+1807; PSR J1012+5307; radiation mechanisms: non-thermal; radiation mechanisms: thermal

Domains: Solar and Stellar Astrophysics [astro-ph.SR]

N.A. Webb, J.F. Olive, D. Barret, M. Kramer, Ismaël Cognard, et al.. XMM-Newton spectral and timing analysis of the faint millisecond pulsars PSR J0751+1807 and PSR J1012+5307. Astronomy and Astrophysics - A&A, 2004, 419 (1), pp.269-276. ⟨10.1051/0004-6361:20040069⟩. ⟨insu-02886678⟩