6533b831fe1ef96bd1298522
RESEARCH PRODUCT
On the Optical Counterpart of SAX J1808.4-3658 during Quiescence: Evidence for an Active Radio Pulsar?
F. D'antonaN. R. RobbaLuciano BurderiG. LavagettoVincenzo TestaR. IariaT. Di Salvosubject
PhysicsAccretion (meteorology)Astrophysics::High Energy Astrophysical PhenomenaAstronomyAstronomy and AstrophysicsAstrophysics::Cosmology and Extragalactic AstrophysicsAstrophysicsBinary pulsarRotational energyLuminosityNeutron starPulsarSpace and Planetary ScienceMillisecond pulsarAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsAstrophysics::Galaxy AstrophysicsX-ray pulsardescription
The optical counterpart of the binary millisecond X-ray pulsar SAX J1808.4-3658 during quiescence was detected at V =21.5 mag, inconsistent with intrinsic emission from the faint companion star. We propose that the optical emission from this system during quiescence is due to the reprocessing by the companion star and a remnant accretion disk of the rotational energy released by the fast spinning neutron star, switched on, as magneto-dipole rotator (radio pulsar), during quiescence. In this scenario the companion behaves as a bolometer, reprocessing in optical the intercepted fraction of the power emitted by the pulsar. This reprocessed fraction depends only on known binary parameters. Thus the blackbody temperature of the companion can be predicted and compared with the observations. Our computations indicate that the observed optical magnitudes are fully consistent with this hypothesis. In this case the observed optical luminosity may be the first evidence that a radio pulsar is active in this system during quiescence.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2003-12-31 | Chinese Journal of Astronomy and Astrophysics |