Discovery of an X-ray pulsar in the LMC with ROSAT.
Abstract
The authors have discovered coherent 13.7 s pulsations from EXO 053109-6609.2, a Be transient in the Large Magellanic Cloud, with the ROSAT PSPC. The pulsations are present in several observations spread over 1.6 yr, covering intrinsic source luminosities from 1×1035 to 3×1036erg s-1 (E = 0.1-2.4 keV, d = 50 kpc). The authors determined a barycentric pulse period of 13.67133±0.00005 s at JD 2448560.658 with a rate of period change of +(1.5±0.1)×10-8 during 3.3 d, which exceeds the long-term trend by at least one order of magnitude. Under the assumption that the observed period change is predominantly caused by Doppler shifts, Porb can be constrained to the range from 4 to 40-70 d, for orbital eccentricities from e = 0.0-0.3, respectively. An orbital solution with Porb = 25.4 d, ax = 200 lt-s, e ≈ 0.1, and i ≈ 50°, is consistent with all observed pulse periods and source luminosities, suggesting a neutron star with a magnetic field B ≈ 3·1012G. With the discovery of pulsations EXO 053109-6609.2 becomes the third Be/X-ray pulsar known in the Large Magellanic Cloud.
- Publication:
-
Roentgenstrahlung from the Universe
- Pub Date:
- February 1996
- Bibcode:
- 1996rftu.proc..131D
- Keywords:
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- X-Ray Binaries: Be Stars;
- X-Ray Binaries: X-Ray Pulsars;
- X-Ray Binaries: Neutron Stars;
- X-Ray Pulsars: Magellanic Clouds