Centaurus A (NGC 5128) at 2 keV--2. 3 MeV: HEAO 1 observations and implications
The nearby active-nucleus galaxy Centaurus A (NGC 5128) has been studied at 2 keV--2.3 MeV using data from both the UCSD/MIT hard X-ray and low energy ..gamma..-ray instrument and from the GSFC/CIT cosmic X-ray experiment on HEAO 1. We find that an E/sup -1.60plus-or-minus0.03/ power law spectrum breaking to E/sup -2.0plus-or-minus0.2/ at 140 keV best describes the 1978 January and July data. The average intensity was 50% higher during the January observations. We have searched our data for faster variations and set limits in several energy ranges over times from fractions of a day to several days. Upper limits to unresolved lines at 511 keV and 1.6 MeV are 6.5 x 10/sup -4/ photons cm/sup -2/ s/sup -1/ and 2.2 x 10/sup -4/ photons cm/sup -2/ s/sup -1/, respectively, at the 90% confidence level. Continuation of the observed power law to higher energies is used to constrain various models of energy generation in the nucleus of NGC 5128.
- Research Organization:
- Department of Physics and Center for Astrophysics and Space Science, University of California at San Diego
- OSTI ID:
- 6386709
- Journal Information:
- Astrophys. J.; (United States), Vol. 244:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Upper limits to the annihilation radiation luminosity of Centaurus A
Radio and X-ray variability of the nucleus of Centaurus A (NGC 5128)
Related Subjects
GENERAL PHYSICS
GALAXY NUCLEI
COSMIC X-RAY SOURCES
X-RAY SPECTRA
X-RAY GALAXIES
BLACK HOLES
COMPTON EFFECT
EMISSION
GALAXIES
RADIO GALAXIES
STAR ACCRETION
VARIATIONS
BASIC INTERACTIONS
COSMIC RADIO SOURCES
COSMIC RAY SOURCES
ELASTIC SCATTERING
ELECTROMAGNETIC INTERACTIONS
INTERACTIONS
SCATTERING
SPECTRA
STAR EVOLUTION
640103* - Astrophysics & Cosmology- Quasi-Stellar
Radio
& X-Ray Sources- (-1987)