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Searches for millisecond pulsations in low-mass X-ray binaries, 2Coherent millisecond X-ray pulsations are expected from low-mass X-ray binaries (LMXBs), but remain undetected. Using the single-parameter Quadratic Coherence Recovery Technique (QCRT) to correct for unknown binary orbit motion, we have performed Fourier transform searches for coherent oscillations in all long, continuous segments of data obtained at 1 ms time resolution during Ginga observations of LMXB. We have searched the six known Z sources (GX 5-1, Cyg X-2, Sco X-1, GX 17+2, GX 340+0, and GX 349+2), seven of the 14 known atoll sources (GX 3+1. GX 9+1, GX 9+9, 1728-33. 1820-30, 1636-53 and 1608-52), the 'peculiar' source Cir X-1, and the high-mass binary Cyg X-3. We find no evidence for coherent pulsations in any of these sources, with 99% confidence limits on the pulsed fraction between 0.3% and 5.0% at frequencies below the Nyquist frequency of 512 Hz. A key assumption made in determining upper limits in previous searches is shown to be incorrect. We provide a recipe for correctly setting upper limits and detection thresholds. Finally we discuss and apply two strategies to improve sensitivity by utilizing multiple, independent, continuous segments of data with comparable count rates.
Document ID
19950036465
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Vaughan, B. A.
(Univ. of Amsterdam Amsterdam, Netherlands)
Van Der Klis, M.
(Univ. of Amsterdam Amsterdam, Netherlands)
Wood, K. S.
(Naval Research Lab. Washington, DC, United States)
Norris, J. P.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hertz, P.
(Naval Research Lab. Washington, DC, United States)
Michelson, P. F.
(Stanford Univ. Stanford, CA, United States)
Paradijs, J. Van
(Univ. of Amsterdam Amsterdam, Netherlands)
Lewin, W. H. G.
(Massachusetts Inst. of Tech., Cambridge, MA United States)
Mitsuda, K.
(Inst. of Space and Astronautical Science Sagamihara, Kanagawa, Japan)
Penninx, W.
(TWI Delft, Netherlands)
Date Acquired
August 16, 2013
Publication Date
November 1, 1994
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 435
Issue: 1
ISSN: 0004-637X
Subject Category
Astronomy
Accession Number
95A68064
Funding Number(s)
CONTRACT_GRANT: NAG8-286
CONTRACT_GRANT: NATO-RG-331/88
Distribution Limits
Public
Copyright
Other

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