The high-energy pulsed x-ray spectrum of Her X-1 as observed with OSO-8. [16 to 280 keV]

Technical Report · Fri Dec 01 04:00:00 EST 1978

OSTI ID:5792398

Maurer, G S; Dennis, B R; Coe, M J; Crannell, C J; Cutler, E P

Her X-1 was observed from 1977 August 30 to September 10 using the High-Energy X-Ray Scintillation Spectrometer on board the OSO-8 satellite. The observation, during which the source was monitored continually for nearly an entire on-state, covered the energy range from 16 to 280 keV. Pulsed flux measurements as a function of binary orbit and binary phase are presented for energies between 16 and 98 keV. The pulsed flux between 16 and 33 keV exhibited a sharp decrease following the fourth binary orbit and was consistent with zero pulsed flux thereafter. The pulsed spectrum was fitted with a power law, a thermal spectrum without features, and a thermal spectrum with a superposed gaussian centered at 55 keV. The latter fit has the smallest value of chi-square per degree of freedom, and the resulting integrated line intensity is (1.5/sup +4/ /sup 1/-/sub 1/ /sub 4/) x 0.001 photons s/sup -1/cm/sup -2/ for a width of 3.1/sup +9/ /sup 1/-/sub 2/ /sub 6/ keV.2.6 keV. This result, while of low statistical significance, agrees with the value observed by Trumper (1978) during the same On-state.

• Research Organization: National Aeronautics and Space Administration, Greenbelt, MD (USA). Goddard Space Flight Center
• OSTI ID: 5792398
• Report Number(s): N-79-16748
• Country of Publication: United States
• Language: English

Related Subjects

640103* -- Astrophysics & Cosmology-- Quasi-Stellar
Radio
& X-Ray Sources-- (-1987)
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
ELECTROMAGNETIC RADIATION
ENERGY RANGE
FLUX DENSITY
KEV RANGE
KEV RANGE 10-100
KEV RANGE 100-1000
MEASURING INSTRUMENTS
ORBITING SOLAR OBSERVATORIES
PULSES
RADIATION DETECTORS
RADIATIONS
RADIOWAVE RADIATION
SATELLITES
SCINTILLATION COUNTERS
SHORT WAVE RADIATION
SPECTRA
X-RAY SPECTRA