Period changes in the X-ray pulsar GX 1+4.
Abstract
The binary X-ray source GX 1 + 4 was observed during a balloon flight in November, 1986. The source was in a relatively high intensity state. Time analysis of the data shows that the pulsation period was 111.8 + or - 1.0 s indicating that one or more episodes of spin-down occurred between 1980 and 1986. Folded pulse profiles are very broad with an indication of a notch at the peak. Evidence has been found for a correlation between hard X-ray intensity and phase of the proposed 304 day orbital period. The time averaged intensity since 1980 is an order of magnitude lower than during the 1970s. A survey of the post 1980 data shows that several reversals of the period derivative have occurred. Spin-up at the rates typical of the 1970s has been followed by a dramatic spin-down episode with dP/dt greater than 2.4 x 10 to the -7th s/s.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- 1989
- DOI:
- 10.1017/S1323358000023249
- Bibcode:
- 1989PASA....8..166G
- Keywords:
-
- Neutron Stars;
- Pulsars;
- Symbiotic Stars;
- X Ray Binaries;
- M Stars;
- Periodic Variations;
- Stellar Mass Accretion;
- Stellar Orbits;
- X Ray Spectra;
- Astrophysics