X-ray follow-up observations of the two γ-ray pulsars PSR J1459–6053 and PSR J1614–2230

B. Pancrazi (1) , N. A. Webb (1) , W. Becker (2, 3) , Ismaël Cognard (4, 5) , Lucas Guillemot (2) , A. B. Hill (6) , M. Jackson (7, 8) , R. P. Mignani (9, 10) , N. Rea (11)

1 IRAP - Institut de recherche en astrophysique et planétologie
2 MPIFR - Max-Planck-Institut für Radioastronomie
3 MPE - Max-Planck-Institut für Extraterrestrische Physik
4 LPC2E - Laboratoire de Physique et Chimie de l'Environnement et de l'Espace
5 USN - Unité Scientifique de la Station de Nançay
6 School of Physics and Astronomy [Southampton]
7 Stockholm University
8 Department of Physics Optics, Royal Institute of Technology (Suède)
9 MSSL - Mullard Space Science Laboratory
10 Institute of Astronomy
11 ICE-CSIC - Institut de Ciencies de l'Espai [Barcelona]

Aims. We have observed two newly detected γ-ray pulsars, PSR J1459−6053 and PSR J1614−2230, in the X-ray domain with XMM-Newton to try to enlarge the sample of pulsars for which multi-wavelength data exist. We use these data with the aim of understanding the pulsar emission mechanisms of these pulsars. Methods. We analysed the X-ray spectra to determine whether the emission emanates from the neutron star surface (thermal emission) or from the magnetosphere (non-thermal emission) and compared this to the region in the magnetosphere in which the γ-ray emission is generated. Furthermore, we compared the phase-folded X-ray lightcurves with those in the γ-ray and, where possible, radio domains, to elicit additional information on the emission sites. Results. J1459−6053 shows X-ray spectra that are best fitted with a power law model with a photon index Γ = 2.10+1.24 −0.85. The γ-ray data suggest that either the slot gap or the outer gap model may be best to describe the emission from this pulsar. Analysis of the X-ray lightcurve folded on the γ-ray ephemeris shows modulation at the 3.7σ level in the 1.0−4.5 keV domain. Possible alignment of the main γ-ray and X-ray peaks also supports the interpretation that the emission in the two energy domains emanates from similar regions. The millisecond pulsar J1614−2230 exhibits an X-ray spectrum with a substantial thermal component, where the best-fitting spectral model is either two blackbodies, with kT = 0.15+0.04 −0.04 and 0.88+2.54 −0.54 keV or a blackbody with similar temperature to the previous cooler component, kT = 0.13+0.04 −0.02 keV and a power law component with a photon index Γ = 1.25+2.30 −1.75. The cooler blackbody component is likely to originate from the hot surface at the polar cap. Analysis of the X-ray lightcurve folded on the radio ephemeris shows modulation at the 4.0σ level in the 0.4−3.0 keV domain.

Keywords: X-rays: stars; pulsars: individual: PSR J1459−6053; radiation mechanisms: thermal; stars: neutron; radiation mechanisms: non-thermal – pulsars: individual: PSR J1614−2230

Domains: Sciences of the Universe [physics]; Astrophysics [astro-ph]; Physics [physics]

B. Pancrazi, N. A. Webb, W. Becker, Ismaël Cognard, Lucas Guillemot, et al.. X-ray follow-up observations of the two γ-ray pulsars PSR J1459–6053 and PSR J1614–2230. Astronomy and Astrophysics - A&A, 2012, 544, A108 (6 p.). ⟨10.1051/0004-6361/201117888⟩. ⟨insu-01253805⟩