Observations of a hard X-ray component in the spectrum of Nova Ophiuchi

Abstract

view Abstract Citations (30) References (34) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Observations of a hard X-ray component in the spectrum of Nova Oph. Wilson, C. K. ; Rothschild, R. E. Abstract The spectrum and time variation of Nova Ophiuchi (H1705-25) in the 10-200 keV range as measured by the UCSD/MIT instruments aboard HEAO 1 during the period 1977 August 25 to September 28 are reported. The composite curve is best fitted by a kT = 2 keV thin thermal bremsstrahlung model below 10 keV and a separate hard X-ray component fitted equally well by a power-law component with photon index 2.19 + or - 0.06 or a kT = 32.1 + or - 2.4 keV thermal bremsstrahlung model. This is the first observation of a hard tail in the spectrum of a transient X-ray source with sufficient statistical significance to allow a detailed study of its spectral and temporal variability. It is found that the intensity variations of the high-energy X-rays are consistent with the variability at lower energies (3-6 keV), but no hard X-ray spectral index variability is found on time scales from 2 days to 2 weeks. The results can be interpreted as due to accretion onto a neutron star (or possibly onto a black hole) that may also be surrounded by an extended corona. Publication: The Astrophysical Journal Pub Date: November 1983 DOI: 10.1086/161483 Bibcode: 1983ApJ...274..717W Keywords: Binary Stars; Neutron Stars; Novae; Stellar Mass Accretion; X Ray Sources; Black Holes (Astronomy); Bremsstrahlung; Heao 1; Light Curve; Ophiuchi Clouds; Stellar Spectra; Thermal Radiation; X Ray Spectra; Astrophysics full text sources ADS | data products SIMBAD (4)