NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
the high energy x-ray spectrum of 4u 1700-37 observed from oso 8The most intense hard X-ray source in the confused region in Scorpius has been identified as 4U 1700-37 (=HD 153919). Observations extending over three binary periods in 1978 September were carried out with the high-energy X-ray spectrometer on OSO 8. The 3.4 day modulation is seen above 20 keV with the intensity during eclipse being consistent with zero flux. The photonumber spectrum from 20 to 150 keV is well represented by a single power law with a photonumber spectral index of -2.77 + or - 0.35 or by a thermal bremsstrahlung spectrum with kT = 27 (+15, -7)keV. The counting rate above 20 keV outside of eclipse shows no evidence for the 96.8 minute X-ray modulation previously reported at lower energies. Despite the difficulties that exist in reconciling both the lack of periodic modulation in the emitted X-radiation and the orbital dynamics of the system with our currently accepted theories of the evolution and physical properties of neutron stars, the observed properties of 4U 1700-37 are all consistent with the source being a spherically accreting neutron star rather than a black hole.
Document ID
19800056483
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Dolan, J. F.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Coe, M. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Crannell, C. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Dennis, B. R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Frost, K. J.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Orwig, L. E.
(NASA Goddard Space Flight Center Laboratory for Astronomy and Solar Physics, Greenbelt, Md., United States)
Maurer, G. S.
(NASA Goddard Space Flight Center Laboratory for Astronomy and Solar Physics, Greenbelt, Md.; Catholic University of America, Washingt, United States)
Date Acquired
August 10, 2013
Publication Date
May 15, 1980
Publication Information
Publication: Astrophysical Journal
Subject Category
ASTRONOMY
Funding Number(s)
CONTRACT_GRANT: NSG-5066
Distribution Limits
Public
Copyright
Other