| dc.description.abstract | In this thesis, I report the observations and analysis results for black hole binaries Swift J1753.5-0127 and A0620-00 for their timing properties with Lulin One-meter Telescope (LOT) during 2008 and 09.
Swift J175.5-0127 was first observed after its 2005 outburst, and its optical band remains bright to date. Zurita et al. (2008) claimed that the 3.24 hrs modulation is the superhump period from its complex modulation profile. However, it is not conscientious enough to determine only by the modulation profile except other properties, i.e. period change . A0620-00 stayed in X-ray quiescent state after its 1975 outburst, but Cantrell et al. (2008) proposed a 30-days period is shown in the color-magnitude diagram. If this is caused by the disk precession, the superhump phenomenon may exist in this system. Therefore, we analyzed the variations of Swift J1753.5-0127 and A0620-00 to verify if these two systems exist superhump phenomena.
We set up a procedure to get the light curves, including the fundamental data reduction and reexamining the problem for the traditional standard star calibration, and reconstructing a reasonable fitting process. We also applied this concept into the differential photometry to minimize the effect of airmass and extinction as we do timing analysis.
After removing the daily trend, we performed Lomb-Scargle (LS) Periodogram and Phase Disperiosn Minimization (PDM) to calculate the most probable periods of modulation. Then we used Period04 to do multi-sinusoidal fitting and derive the model of modulation. After removing the ~3.2 hrs modulation, no clear side-band was found in the spectra of Swift J1753.5-0127’s residual light curves. A0620-00 showed pure ellipsoidal modulation, and no other significant signal was detected after removing its orbital variation. The best period of Swift J1753.5-0127 evaluated from this method is 3.2440 ±0.0002 hrs, consistent with the one proposed by Zurita et al. (2008) (3.2454±0.0080 hrs). The same analysis technique was applied for A0620-00 and yielded a period of 7.75229±0.00004 hrs, also consistent with the orbital period proposed by McClintock & Remillard (1986) ( 7.75234±0.00010 hrs).
From the analysis of window function, we found the residual signals of Swift J1753.5 -0127 may be the coupling of 3.24 hrs period and window function. We attempted to evaluate the period derivative from O-C method. But the large observation gaps also made the O-C results not significant. Therefore, we still cannot determine the 3.24 hrs period is the orbital period or the superhump one. The 30-day period of A0620-00 is unlikely caused by superhump phenomenon, but from other unknown origins.
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