2026-09-18T20:27:29Zhttps://dspace.mit.edu/server/oai/requestoai:dspace.mit.edu:1721.1/286482022-01-13T07:54:41Zcom_1721.1_7582com_1721.1_7581col_1721.1_131022
Deepto Chakrabarty.
Wang, Zhongxiang, 1968-
Massachusetts Institute of Technology. Dept. of Physics.
Massachusetts Institute of Technology. Department of Physics
2005-09-27T17:30:15Z
2005-09-27T17:30:15Z
2004
2004
http://hdl.handle.net/1721.1/28648
58965153
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.
Includes bibliographical references (p. 133-149).
(cont.) to the XPS in SNR RCW 103. The multiple IR band measurements of 1E 1048.1-5937 provide marginal evidence for spectral flattening, and cannot rule out an accretion disk scenario for AXPs.
In this thesis, I present multiwavelength studies of phenomena related to accretion disks around compact objects. The observations were made mainly with ground-based telescopes and the Hubble Space Telescope. I observed several known and candidate ultracompact low-mass X-ray binaries (LMXBs) and found that their optical spectra all show a lack of hydrogen emission lines, supporting the theoretical prediction that mass donors in ultracompact LMXBs must be H-depleted. Time-resolved photometry of the candidate source 4U 1543-624 revealed an 18 minute orbital periodicity, verifying the ultracompact nature of this binary. These studies strongly support the identification of several candidate systems with similar X-ray spectral features as ultracompact binaries. In the ultracompact binary 4U 1820-30, which has the shortest orbital period (685 s) among the known LMXBs, I discovered a 692-s periodicity from its far-ultraviolet (FUV) time series data. I interpret this longer-period FUV signal as a superhump oscillation, arising from a tidal resonance in the accretion disk of an extreme-mass-ratio binary. I also present multiband imaging of the fields surrounding five newly discovered X-ray millisecond pulsars (MSPs) in an effort to identify and study their optical/IR counterparts. For the MSP SAX J1808.4-3658, the optical light curve taken during its 1998 X-ray outburst shows an exponential decay in intensity, roughly following the X-ray light curve early in the outburst. An optical counterpart of XTE J1814-338 was also detected. Finally, optical/IR observations of anomalous X-ray pulsars (AXPs) and X-ray point sources (XPSs) in young supernova remnants (SNRs) identified the IR counterpart to the AXP 1E 1048.1-5937 and a likely IR counterpart
by Zhongxiang Wang.
Ph.D.
149 p.
6198989 bytes
6218958 bytes
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application/pdf
en_US
Massachusetts Institute of Technology
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http://dspace.mit.edu/handle/1721.1/7582
Physics.
Multiwavelength studies of accretion disks around compact objects
Multi wavelength studies of accretion disks around compact objects
Thesis
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Publication
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<Abstract>(cont.) to the XPS in SNR RCW 103. The multiple IR band measurements of 1E 1048.1-5937 provide marginal evidence for spectral flattening, and cannot rule out an accretion disk scenario for AXPs.</Abstract>
<Abstract>In this thesis, I present multiwavelength studies of phenomena related to accretion disks around compact objects. The observations were made mainly with ground-based telescopes and the Hubble Space Telescope. I observed several known and candidate ultracompact low-mass X-ray binaries (LMXBs) and found that their optical spectra all show a lack of hydrogen emission lines, supporting the theoretical prediction that mass donors in ultracompact LMXBs must be H-depleted. Time-resolved photometry of the candidate source 4U 1543-624 revealed an 18 minute orbital periodicity, verifying the ultracompact nature of this binary. These studies strongly support the identification of several candidate systems with similar X-ray spectral features as ultracompact binaries. In the ultracompact binary 4U 1820-30, which has the shortest orbital period (685 s) among the known LMXBs, I discovered a 692-s periodicity from its far-ultraviolet (FUV) time series data. I interpret this longer-period FUV signal as a superhump oscillation, arising from a tidal resonance in the accretion disk of an extreme-mass-ratio binary. I also present multiband imaging of the fields surrounding five newly discovered X-ray millisecond pulsars (MSPs) in an effort to identify and study their optical/IR counterparts. For the MSP SAX J1808.4-3658, the optical light curve taken during its 1998 X-ray outburst shows an exponential decay in intensity, roughly following the X-ray light curve early in the outburst. An optical counterpart of XTE J1814-338 was also detected. Finally, optical/IR observations of anomalous X-ray pulsars (AXPs) and X-ray point sources (XPSs) in young supernova remnants (SNRs) identified the IR counterpart to the AXP 1E 1048.1-5937 and a likely IR counterpart</Abstract>
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