Astronomy and Astrophysics – Astronomy
Scientific paper
Jan 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992phdt........12g&link_type=abstract
Ph.D. Thesis Massachusetts Inst. of Tech., Cambridge.
Astronomy and Astrophysics
Astronomy
27
Active Galactic Nuclei, Heao 1, Imaging Techniques, Sky Surveys (Astronomy), X Ray Imagery, X Ray Sources, Collimators, Far Infrared Radiation, Infrared Astronomy Satellite, Iue, Luminosity, Near Infrared Radiation, Statistical Distributions, Ultraviolet Radiation, X Rays
Scientific paper
The LASS (Large Area Sky Survey) experiment, which flew aboard the HEAO-1 spacecraft, carried out a 2-20 keV survey of the sky during 1977-1978. The X-ray sources from this survey make up the LASS catalog (Wood et al. 1979). Optical counterparts have been identified for greater than 86 percent of the LASS sources above a flux of approx. 0.95 microns (mu)Jy Q 5 keV (Remillard 1992b). The LASS error boxes, along with the more precise positions from the Modulation Collimator (MC) X-ray experiment (also aboard HEAO-1), subsequent X-ray imaging, and optical search techniques were all used to identify the LASS sources. From these identifications, a high-latitude (absolute value of b greater than 20 deg.), flux limited (greater than or equal to 0.95 (mu)Jy) sample of 96 emission line Active Galactic Nuclei (AGN) have been selected for study. The sample is referred to as the LMA (for the LASS/MC identified sample of AGN). The objective of this work is to produce multi-frequency spectra of this sample of objects, in order to determine and interpret the statistical properties of the sample over nearly the full range of observable wavelengths. Data were obtained for as much of the radio through hard X-ray (less than 20 keV) spectrum as possible for each object in the LMA. Radio, near infrared, and other measurements were taken from the literature, far IR fluxes were extracted from co-added observations from IRAS, UV spectra were obtained from the IUE archives, and original observations were performed (with the help of collaborators) in the radio, near IR, optical, UV, and X-ray to fulfill this goal. Correlation studies of the continuum bands found poor correlations of X-ray and radio flux, good correlations for 12 and 26 micron flux with X-ray flux, excellent correlations for optical and near IR fluxes with X-rays, and poor correlations of UV and X-ray fluxes. Correlation studies of the line and X-ray continuum flux yield a good correlation between the flux of (OIII), the strongest narrow emission line, and X-ray flux. The hard X-ray Luminosity Function (LF) of the LMA can be roughly described by a power law of slope -2.49 plus or minus 0.02 from 1042-1048 erg s-1, but the function steepens with increasing luminosity.
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