above.

Energy dependence of the 1 Hz QPO
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In Fig. \[energy\] we show the energy dependence of the 1 Hz QPO. The points in the figure refer to the observation (one per outburst) for which the fractional rms of the 1 Hz QPO in the 2-60 keV energy band was the highest ($110.5\%$ rms in 2000, ObsId 40035-01-04-01, total exposure 7 ks; $117\%$ rms in 2002, ObsId 70080-03-15-00, total exposure 2 ks; $125\%$ rms in 2005, ObsId 91418-01-02-05, total exposure 1.2 ks). In these observations the characteristic frequencies of the 1 Hz QPO and its overtone form clear peaks in the power spectrum and $\rm\,Q>2$.

The energy spectrum is hard, rising by a factor of 1.5-1.7 between 2 and 17 keV. Upper limits (98 $\%$ confidence level) in the 17-60 keV band were: $114\%$ rms for 2000, $157\%$ rms for 2002 and $155\%$ rms for 2005.

Jumps in 401 Hz pulse phases related to strength of 1 Hz QPO {#phasejump}
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During the first re-flare of the 2002 outburst, the 1 Hz QPO becomes very broad and then disappears. When the QPO becomes very broad and its fractional rms amplitude suddenly drops from $\sim 50\%$ down to $10\%$, a 