What is the nature of rx j0720.4-3125?

RX J0720.4-3125 has recently been identified as a pulsating soft X-ray source in the ROSAT all-sky survey with a period of 8.391 s. Its spectrum is well characterized by a black-body with a temperature of

8 \times 10^5

K. We propose that the radiation from this object is thermal emission from a cooling neutron star. For this black-body temperature we can obtain a robust estimate of the object's age of

\sim 3 \times 10^5

yr, yielding a polar field

\sim 10^{14}

G for magnetic-dipole spin down and a value of

{\dot P}

compatible with current observations.

References(5)

Figures(0)

- Astrophys.J. 287 244

- Mon.Not.Roy.Astron.Soc. 213 313

- Astrophys.J. 442 17

- Astron.Astrophys. 299 41

Evidence for magnetic field decay in rx j0720.4-3125

John C.L. Wang

- Astrophys.J.Lett. 486 (1997) L119
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e-Print:
- astro-ph/9706288
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DOI:
- 10.1086/310852