Peculiar pulse profile of GX 1+4 observed in the spin-down phase.
Abstract
Observations of GX 1+4 made with Ginga in March 1987 and March 1988 have revealed the following drastic changes in the system: (1) spin-down at an average rate of 1.2 x 10 to the-2nd/yr, (2) an extended low state with a luminosity of 1.2 x 10 to the 36th erg/s in 1987 and 5.7 x 10 to the 36th erg/s in 1988, and (3) a peculiar pulse profile witha sharp dip associated with a narrow maximum. One possible interpretation of the rapid spin-down rate requires a magnetic dipole moment of 5 x 10 to the 31st G cu cm. However, this interpretation seems implausible. Instead, a retrograde rotating accretion disk is proposed to explain the present spin-down of GX 1+4 and its rate of change. The dip structure with a narrow maximum seems to result from resonance scattering of photons at the accretion column above the magnetic pole.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- 1989
- Bibcode:
- 1989PASJ...41..427D
- Keywords:
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- Accretion Disks;
- Magnetic Dipoles;
- Proportional Counters;
- Pulsars;
- Spaceborne Astronomy;
- X Ray Binaries;
- Galactic Nuclei;
- Japanese Space Program;
- Milky Way Galaxy;
- X Ray Sources;
- Astrophysics