%0 Journal Article
%T Spectral and timing analysis of the mHz QPOs in the neutron-star low-mass X-ray binary 4U 1636-53
%A Ming Lyu
%A Mariano Mendez
%A Guobao Zhang
%A L. Keek
%J Physics
%D 2015
%I arXiv
%R 10.1093/mnras/stv1971
%X We investigate the spectral and timing properties of the millihertz quasi-periodic oscillations (mHz QPOs) in neutron-star low-mass X-ray binary 4U 1636-53 using XMM-Newton and Rossi X-ray Timing Explorer (RXTE) observations. The mHz QPOs in the XMM-Newton/RXTE observations show significant frequency variation and disappear right before type I X-ray bursts. We find no significant correlation between the mHz QPO frequency and the temperature of the neutron-star surface, which is different from theoretical predictions. For the first time we observed the full lifetime of a mHz QPO lasting 19 ks. Besides, we also measure a frequency drift timescale around 15 ks, we speculate that this is the cooling timescale of a layer deeper than the burning depth, possibly heated by the previous burst. Moreover, the analysis of all X-ray bursts in this source shows that all type I X-ray bursts associated with the mHz QPOs are short, bright and energetic, suggesting a potential connection between mHz QPOs and He-rich X-ray bursts.
%U http://arxiv.org/abs/1508.06256v1