The kilo-parsec properties of blazars
Abstract
In this dissertation, we explore the properties of Active Galactic Nuclei (AGN) on kiloparsec scales at a radio frequency of 1.4 GHz. These properties include flux density, luminosity, and morphology. We compare these kiloparsec scale properties to similar properties on the parsec scale at 15 GHz, such as jet misalignment angle and other parsec scale properties, such as γ-ray flux density and luminosity. The AGN studied are the 135 from the Monitoring Of Jets in Active galaxies using VLBA Experiments (MOJAVE) survey, MOJAVE-I sample. Using Monte Carlo Simulations with matching sample statistics, We find that the most likely distribution of intrinsic pc-to-kpc scale bend angles is a uniform distribution with a range of 0°– ∼ 10°. The maximum bend angle is unlikely to be < 5° or > 30°. Furthermore, power law distributions with an index > 1.25 or < −0.5 are ruled out at the 95% confidence level. Narrowly peaked Gaussian distributions are likewise excluded. Using the ASURV statistics package, We find that gamma-ray (Lγ ) and kpc-scale radio luminosities (Lext) are strongly correlated. Since Lext is correlated with jet power, it is likely that this is indicative of a mutual dependence of intrinsic γ-ray and extended radio emission on jet power. Partial correlation coefficients increase if Lγ is de-boosted by either the synchrotron-self Compton or external Compton models. Furthermore, no convincing correlation between Lγ and unresolved VLA core luminosity (Lc) is present. Based on previous findings that use median VLBA flux densities a correlation with L γ may be present. However, considering that the VLA data are from a single epoch and not taken simultaneously with the γ-ray data, this greatly reduces the chances of detecting Lc - γ-ray correlations after redshift bias is factored out. Although a recent discovery of extended γ-ray emission from Centaurus A could suggest a contribution to the Lγ-Lext correlation, this emission is diffuse and most MOJAVE sources are at large luminosity distances. The presence of diffuse γ-ray emission is therefore unlikely to affect our conclusions regarding the Lext and L γ correlation.
Degree
Ph.D.
Advisors
Lister, Purdue University.
Subject Area
Astronomy
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