Long term variations in RXJ 0720
De
Vries et al., 2004
Vink,
et al, 2004
A gradual, long term change in the shape of the X-ray spectrum AND in the pulse profile
From rev. 78 (13 May 2000) to rev.711 (27-10-2003) the pulse profile become narrower and the pulsed fraction increases from ~20% to ~ 35%
Pulse profile of
0720 in the 0.1-1.2 keV band and hardness ratio. The best
sinusoidal fit to rev. 0078 (solid line) is overplotted on the light curve of
rev. 0711 for comparison.