Discovery of X-Rays from the Old and Faint Pulsar J1154-6250

: Igoshev AP, Tsygankov SS, Rigoselli M, Mereghetti S, Popov SB, Elfritz JG, Mushtukov AA

Publisher: IOP PUBLISHING LTD

: 2018

: Astrophysical Journal

: ASTROPHYSICAL JOURNAL

: ASTROPHYS J

: ARTN 116

: 865

: 2

: 6

: 0004-637X

DOI: https://doi.org/10.3847/1538-4357/aadd93

: https://research.utu.fi/converis/portal/detail/Publication/36048050

We report on the first X-ray observation of the 0.28 s isolated radio pulsar PSR J1154-6250 obtained with the XMM-Newton observatory in 2018 February. A point-like source is firmly detected at a position consistent with that of PSR J1154-6250. The two closest stars are outside the 3 sigma confidence limits of the source position and thus unlikely to be responsible for the observed X-ray emission. The energy spectrum of the source can be fitted equally well either with an absorbed power law with a steep photon index Gamma approximate to 3.3 or with an absorbed blackbody with temperature kT = 0.21 +/- 0.04 keV and emitting radius R-BB approximate to 80 m (assuming a distance of 1.36 kpc). The X-ray luminosity of 4.4 x 10(30) erg s(-1) derived with the power-law fit corresponds to an efficiency of eta(X) = L-X(unabs) /(E) over dot= 4.5 x 10(-3), similar to those of other old pulsars. The X-ray properties of PSR J1154-6250 are consistent with an old age and suggest that the spatial coincidence of this pulsar with the OB association Cm OB1 is due to a chance alignment.

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