Spectral changes during the 0.1-4 Hz quasi-periodic oscillations in the black hole X-ray binary XTE J1550-564

In this thesis, we describe the analysis of 0.1-4 Hz quasi-periodic oscillations (QPOs) of the black hole X-ray binary XTE J1550-564 using data obtained with the Rossi X-ray Timing Explorer (RXTE) satellite. Data from 13 consecutive observations spanning eight days were included in this analysis. By comparing the spectra of the source when it is in the high intensity phase with the low intensity phase of its QPO cycle, we hoped to gain insight into the cause of QPOs and how they relate to structures and processes in the vicinity of black holes. Like observations from the black hole X-ray binary GRS 1915+105 (Miller and Homan 2005), our observations from XTE J1550-564 showed a significant difference in the Fe ... line equivalent width between the high and low intensities of the QPO for 6 of 13 observations. However, 2 of 13 observations exhibited the opposite effect in that the Fe K [alpha] line equivalent width actually dropped significantly during periods of high intensity. Moreover, we found that the integrated flux of the Fe K [alpha] line was proportional to the flux of the continuum in 5 of 13 observations. Despite these competing effects, the ratios of the low intensity and high intensity spectra indicate an increase in the QPO strength up to about 10 keV, above which it decreases only slightly. We also found dramatic changes in the QPO strength at low energies as the QPO frequency increases. We believe this to be the result of an increase in relative contributions to the spectra as the disk blackbody component becomes more important.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Physics.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2005

Author dc:creator

• Cho, Steven N. (Steven Nicholas)

Advisor dc:contributor.advisor

• Walter H.G. Lewin.

• Physics.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/32312

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/32312