Discovery of burst oscillations near the spin frequency in the intermittent accreting millisecond pulsar HETE J1900.1-2455

Watts, A.; Altamirano, D.; Casella, P.; Cavecchi, Y.; Degenaar, N.; Linares, M.; Patruno, A.; Rea, N.; Soleri, P.; van der Klis, M.; Wijnands, R.
Bibliographical reference

The Astronomer's Telegram, #2004

Advertised on:
4
2009
Number of authors
11
IAC number of authors
0
Citations
2
Refereed citations
1
Description
RXTE observations of the intermittent accreting millisecond X-ray pulsar HETE J1900.1-2455 (Kaaret et al. 2006 ApJ 638, 963; Galloway et al. 2007 ApJ 654, L73) showed a Type I X-ray burst on April 2 2009 (08:57 UTC). We detect strong burst oscillations during the peak and initial decay of the burst, drifting upwards from 375.5 Hz to 376.5 Hz. Maximum Leahy power is in the range 25-45 in 4 independent consecutive 2s bins (using all photons in the 2-60 keV band), putting the detection beyond doubt.