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On the correlation of torque and luminosity in GX 1+4

Chakrabarty, Deepto and Bildsten, Lars and Finger, Mark H. and Grunsfeld, J. M. and Koh, Danny T. and Nelson, Robert W. and Prince, Thomas A. and Vaughan, Brian A. and Wilson, Robert B. (1997) On the correlation of torque and luminosity in GX 1+4. Astrophysical Journal Letters, 481 (1). L101-L105. ISSN 2041-8205. doi:10.48550/arXiv.9703047.

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Over 5 years of daily hard X-ray (.20 keV) monitoring of the 2 minute accretion-powered pulsar GX 1+4 with the Compton Gamma Ray ObservatoryyBATSE large-area detectors has found nearly continuous rapid spin-down, interrupted by a bright 200 day spin-up episode. During spin-down, the torque becomes more negative as the luminosity increases (assuming that the 20–60 keV pulsed flux traces bolometric luminosity), the opposite of what is predicted by standard accretion torque theory. No changes in the shape of the 20–100 keV pulsed energy spectrum were detected, so that a very drastic change in the spectrum below 20 keV or the pulsed fraction would be required to make the 20–60 keV pulsed flux a poor luminosity tracer. These are the first observations that flatly contradict standard magnetic disk accretion theory, and they may have important implications for understanding the spin evolution of X-ray binaries, cataclysmic variables, and protostars. We briefly discuss the possibility that GX 1+4 may be accreting from a retrograde disk during spin-down, as previously suggested.

Item Type:Article
Related URLs:
URLURL TypeDescription
Chakrabarty, Deepto0000-0001-8804-8946
Prince, Thomas A.0000-0002-8850-3627
Additional Information:(c) 1997: The American Astronomical Society. We thank an anonymous referee for helpful comments. This work was funded in part by NASA grants NAG 5-1458 and NAGW-4517. D. C. was supported at Caltech by a NASA GSRP Graduate Fellowship under grant NGT-51184. The NASA Compton Postdoctoral Fellowship program supported D. C. (NAG 5-3109), L. B. (NAG 5-2666), and R. W. N. (NAG 5-3119). L. B. was also supported by Caltech’s Lee A. DuBridge Fellowship, funded by the Weingart Foundation, and by the Alfred P. Sloan Foundation.
Group:Space Radiation Laboratory
Funding AgencyGrant Number
NASANAG 5-1458
NASANAG 5-3109
NASANAG 5-3119
Lee A. DuBridge FellowshipUNSPECIFIED
Weingart FoundationUNSPECIFIED
Alfred P. Sloan FoundationUNSPECIFIED
Non-Subject Keywords:accretion, accretion disks—pulsars: individual (GX 1+4)—stars: neutron—X-rays: stars.
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Other Numbering System NameOther Numbering System ID
Space Radiation Laboratory1997-29
Issue or Number:1
Record Number:CaltechAUTHORS:20141106-103420466
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:51364
Deposited By: Deborah Miles
Deposited On:07 Nov 2014 23:39
Last Modified:02 Jun 2023 01:30

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