X-ray emission from the old pulsar B0950+08

Abstract

We present the timing and spectral analyses of theXMM-newton data on the 17-Myr-old, nearby radio pulsar B0950+08. This observation revealed pulsations of the X-ray flux of the pulsar at its radio period. The pulse shape and pulsed fraction are apparently different at lower and higher energies of the observed 0.2-10 keV energy range, which suggests that the radiation cannot be explained by a single emission mechanism. The X-ray spectrum of the pulsar can be fitted with a power-law model with a photon index about 1.75 and an (isotropic) luminosity about 9.8e29 erg/s in the 0.2-10 keV. Better fits are obtained with two-component, power-law plus thermal, models with index of 1.30 and 9.7e29 erg/s for the power-law component that presumably originates from the pulsar's magnetosphere. The thermal component, dominating at E>0.7 keV, can be interpreted as radiation from heated polar caps on the neutron star surface covered with a hydrogen atmosphere. The inferred effective temperature, radius, and bolometric luminosity of the polar caps are about 1 MK, 250 m, and 3e29 erg/s. Optical through X-ray nonthermal spectrum of the pulsar can be described as a single power-law with index 1.3-1.4 for the two-component X-ray fit. The ratio of the nonthermal X-ray (1-10 keV) luminosity to the nonthermal optical (4000-9000 Å) luminosity is within the range of 1e2-1e3 observed for younger pulsars, which suggests that the magnetospheric X-ray and optical emissions are powered by the same mechanism in all pulsars. An upper limit on the temperature of the bulk of the neutron star surface, inferred from the optical and X-ray data, is about 0.15 MK. We also analyze X-ray observations of several other old pulsars, B2224+65, J2043+2740, B0628-28, B1813-36, B1929+10, and B0823+26.

To be published in ApJ. Nonthermal optical and X-ray luminosities of seven radio pulsars are updated and presented in a new Table. Figure 6 showing the ratios of the luminosities vs. spin-down energy is also updated

References in corpus (19)

• Neutron Star Cooling
• Chandra High-Resolution Camera Observations of the Luminous X-Ray Source in the Starburst Galaxy M82
• Re-examining the X-Ray versus Spin-Down Luminosity Correlation of Rotation Powered Pulsars
• Emission Beam Geometry of Selected Pulsars Derived from Average Pulse Polarization Data
• Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission II. Inverse Compton Radiation Pair Fronts
• The Crab pulsar in the 0.75-30 MeV range as seen by CGRO COMPTEL
• The X-ray Spectrum of the Vela Pulsar Resolved with Chandra
• VLBA Measurement of Nine Pulsar Parallaxes
• Pulsar Polar Cap Heating and Surface Thermal X-Ray Emission I. Curvature Radiation Pair Fronts
• Pulsar Parallaxes at 5 GHz with the Very Long Baseline Array
• Observations of the Crab Nebula and its pulsar in the far-ultraviolet and in the optical
• A Strong, Broad Absorption Feature in the X-ray Spectrum of the Nearby Neutron Star RX J1605.3+3249
• Ultraviolet Emission from the Millisecond Pulsar J0437-4715
• X-ray Radiation from the Millisecond Pulsar J0437-4715
• Mass-to-Radius Ratio for the Millisecond Pulsar J0437-4715
• Optical photometry of the PSR B0656+14 and its neighborhood
• The Vela Pulsar in the Near-Infrared
• Constraining dense-matter superfluidity through thermal emission from millisecond pulsars
• HST Proper Motion confirms the optical identification of the nearby pulsar PSR 1929+10

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