SIMBAD references

1999A&A...345..117K - Astronomy and Astrophysics, volume 345, 117-120 (1999/5-1)

The recent pulse period evolution of SMC X-1.


Abstract (from CDS):

We report observations of SMC X-1 in three new high-intensity states with ROSAT HRI in December 1995, May 1997, and March 1998 in which pulsations with a period of 0.70769 (±0.00006)s, 0.70706 (±0.00001)s, and 0.706707 (±0.00001)s respectively were detected. Combining the pulse periods from observations with ROSAT PSPC in high-intensity states in October 1991 and March 1998, respectively, we obtain the spin-up rate of the pulsar in recent 6.5 years, -{dot}(P)=(1.18±0.06)x10–11s/s, consistent with the average spin-up rate -{dot}(P)=1.2x10–11s/s determined from previous measurements indicating that the stable spin-up has continued. Pulsations with a period of 0.709103 (±0.000003)s were also detected ∼2 weeks after an X-ray turn-off during an X-ray low-intensity state in October 1991, and the period derivative derived within ∼10days is -{dot}(P)≃(1.1±0.7)x10–11s/s. This is consistent with a constant accretion torque in sign and magnitude. The magnitude of the magnetic moment of the pulsar is discussed based on different description of the apparent spin-up behavior.

Abstract Copyright:

Journal keyword(s): accretion, accretion disks - stars: individual: SMC X-1 (SMC) - stars: magnetic fields - stars: neutron - stars: rotation - X-rays: stars

Simbad objects: 5

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