Observational constraints on the origin of the diffuse background radiation between 0. 5 and 2 keV

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1978

OSTI ID:6428416

Nousek, J A

The spatial and spectral nature of the diffuse soft x-ray background has been studied using data from five sounding rocket flights. The analysis of lower energy (0.1 to 0.5 keV) x-rays has been treated elsewhere (Fried, 1978a). The spectrum of the higher energy (2 to 6 keV) x-rays is consistent with 11E/sup -1/ /sup 4/ photons (cm/sup -2/-sec-sr-keV)/sup -1/, and is in agreement with the observations of others. The data at intermediate energies (0.5 to 2.0 keV) are found to admit the possibility of a contribution of extragalactic origin at least as large as the extrapolation of the high energy spectrum. The conclusion of Burstein et al. (1977) that emitting regions with two difffering temperatures are required to explain the soft x-ray background is supported. Further, to reconcile the low and intermediate energy data at three well-measured sky locations, the higher temperature region must be beyond all the galactic neutral gas and the lower temperature region must be closer than almost all the neutral gas. The minimum local pressure (P/k) achievable with this model is of the order 10/sup 4/ cm/sup -3/-K with an emitting extent of about 100 pc. Viable models as to the nature and location of the higher temperature emitting regions are discussed. Enhancements in the intermediate energy intensity are associated with extended galactic sources. The contribution of more distant extended sources is judged insufficient to provide the general sky intensity. The general sky intensity, after removal of identified enhancements, is correlated with galactic latitude and longitude. The observed correlations accept two explanations. The hot emitting region may form a disk structure, external to the galactic neutral gas. Alternatively, non-equilibrium ionization effects in a local plasma may suffice.

• Research Organization: Wisconsin Univ., Madison (USA)
• OSTI ID: 6428416
• Country of Publication: United States
• Language: English

Related Subjects

640101* -- Astrophysics & Cosmology-- Cosmic Radiation
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
BACKGROUND RADIATION
COSMIC GASES
COSMIC RADIATION
ELECTROMAGNETIC RADIATION
ENERGY RANGE
ENERGY SPECTRA
FLUIDS
GASES
IONIZING RADIATIONS
KEV RANGE
KEV RANGE 01-10
ORIGIN
PLASMA
RADIATIONS
ROCKETS
SOFT X RADIATION
SPECTRA
X RADIATION