The Temporal Phenomena of Black Hole Transient XTE J1650-500 in Its 2001-2002 Outburst

Using the data observed by Rossi X-ray Timing Explorer, a systematic study of temporal phenomena of the black-hole transient XTE J1650-500 in its 2001–2002 outburst is presented. By using the time lag in the Fourier frequency domain, three characteristic frequency ranges are analysed, namely the band limited noise, red noise, and QPOs (Quasi-Periodic Oscillations). The properties and evolution behaviours in these frequency ranges may be dominated by different accretion regions. It is commonly believed that the smaller timescale corresponds to the more inner region. The low-hard state and hard intermediate state are especially highlighted. The results of data analysis are discussed in the framework of Lense-Thirring precession. Results are in favor of the disturbance propagation model for explaining the observed time lags. Although the timing analysis in the frequency ranges of band-limited noise and red noise is carried out, and a possibly existed inflection point is found, the model to explain them is still not well established. More work is needed to understand the innermost accretion region.     

On the Black Hole - Bulge Mass Ratios in Narrow-Line Seyfert 1 Galaxies

We present estimated ratios of the central black hole mass to the bulge mass (Mbh/Mbulge) for 15 Narrow Line Seyfert 1 galaxies (NLS1s). It is found that NLS1s apparently have lower mass ratios: the average mass ratio is about 1 × 10-4 with a spread of 2, which is one order of magnitude lower than for Broad Line AGNs and quiescent galaxies. This lower value, as compared to that established essentially for all other types of galaxies, can be accounted for by an underestimation of the black hole masses and an overestimation of the bulge masses in the NLS1s.