A Coherent Timing Solution for the Nearby Isolated Neutron Star Rx J0720.4−3125
نویسنده
چکیده
We present the results of a dedicated effort to measure the spin-down rate of the nearby isolated neutron star RX J0720.4−3125. Comparing arrival times of the 8.39-sec pulsations for data from Chandra we derive an unambiguous timing solution for RX J0720.4−3125 that is accurate to < 0.1 cycles over > 5 years. Adding data from XMM and ROSAT, the final solution yields Ṗ = (6.98 ± 0.02) × 10 s s; for dipole spin-down, this implies a characteristic age of 2 Myr and a magnetic field strength of 2.4 × 10 G. The phase residuals are somewhat larger than those for purely regular spin-down, but do not show conclusive evidence for higher-order terms or a glitch. From our timing solution as well as recent X-ray spectroscopy, we concur with recent suggestions that RX J0720.4−3125 is most likely an off-beam radio pulsar with a moderately high magnetic field. Subject headings: pulsars: individual (RX J0720.4−3125) — stars: neutron — X-rays: stars
منابع مشابه
A Coherent Timing Solution for the Nearby Isolated Neutron Star
We present a phase-connected timing solution for the nearby isolated neutron star RX J1308.6+2127 (RBS 1223). From dedicated Chandra observations as well as archival Chandra and XMM-Newton data spanning a period of five years, we demonstrate that the 10.31-sec pulsations are slowing down steadily at a rate of Ṗ = 1.120(3)× 10 s s. Under the assumption that this is due to magnetic dipole torques...
متن کاملOptical Observations of the Isolated Neutron Star RX J0720.4−3125
RX J0720.4−3125 is an unidentified bright soft X-ray source which shows pulsations at a 8.39 s period and has a thermal spectrum. We present deep B and R band images of its X-ray localization. We find one possible counterpart in the X-ray error box, with magnitudes B = 26.6±0.2 and R = 26.9±0.3. The very high X-ray to optical flux ratio confirms that this object is an isolated neutron star. We ...
متن کاملar X iv : a st ro - p h / 98 03 02 4 v 1 3 M ar 1 99 8 Optical Observations of the Isolated Neutron Star RX J 0720 . 4 − 3125
RX J0720.4−3125 is an unidentified bright soft X-ray source which shows pulsations at a 8.39 s period and has a thermal spectrum. We present deep B and R band images of its X-ray localization. We find one possible counterpart in the X-ray error box, with magnitudes B = 26.6±0.2 and R = 26.9±0.3. The very high X-ray to optical flux ratio confirms that this object is an isolated neutron star. We ...
متن کاملEvidence for precession of the isolated neutron star RX J 0720 . 4 − 3125 ⋆
The XMM-Newton spectra of the isolated neutron star RX J0720.4−3125 obtained over 4.5 years can be described by sinusoidal variations in the inferred blackbody temperature, the size of the emitting area and the depth of the absorption line with a period of 7.1±0.5 years, which we suggest to be the precession period of the neutron star. Precession of a neutron star with two hot spots of differen...
متن کاملThe Nearby Neutron Star Rx J0720.4−3125 from Radio to X-rays
We present radio, optical, ultraviolet, and X-ray observations of the isolated, thermally-emitting neutron star RX J0720.4−3125 using the Parkes radio telescope, the Very Large Array, the Hubble Space Telescope, and the Chandra X-ray Observatory. From these data we show that the optical/UV spectrum of RX J0720.4−3125 is not well fit by a Rayleigh-Jeans tail as previously thought, but is instead...
متن کامل