Altered luminosity functions for relativistically beamed objects. II - Distribution of Lorentz factors and parent populations with complex luminosity functions

Abstract

view Abstract Citations (71) References (2) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Altered Luminosity Functions for Relativistically Beamed Objects. II. Distribution of Lorentz Factors and Parent Populations with Complex Luminosity Functions Urry, C. M. ; Padovani, P. Abstract Relativistic beaming introduces strong selection effects into flux- limited samples because of the considerable Doppler enhancement. In populations where relativistic beaming is important, the ratio of number densities between beam-dominated and parent objects becomes a function of luminosity. Urry and Shafer previously calculated this effect assuming a single Lorentz factor for the bulk motion and a single power-law parent luminosity function with sharp cutoffs. Here we investigate more realistic luminosity functions, required for actual tests of unified theories of active galactic nuclei (AGNs), including double power-law parent luminosity functions and distributions of bulk Lorentz factors for the relativistically beamed component. The observed luminosity function of the beam-dominated objects is generally flatter than the parent luminosity function, so that the number density ratio is a strong function of luminosity and can easily be greater than unity at high luminosities, even for gradual low-luminosity cutoffs in the parent luminosity function. Several characteristic break points can be identified, depending on the details of the parent luminosity function. Our calculations can be used to test unified theories by predicting the observed luminosity function for aligned objects from the luminosity function of the proposed parent population. This procedure is essential when samples are defined by a limit on the total flux, as is frequently the case. Publication: The Astrophysical Journal Pub Date: April 1991 DOI: 10.1086/169870 Bibcode: 1991ApJ...371...60U Keywords: Bl Lacertae Objects; Lorentz Transformations; Luminosity; Relativistic Electron Beams; Active Galactic Nuclei; Spectral Emission; Astrophysics; BL LACERTAE OBJECTS; GALAXIES: JETS; LUMINOSITY FUNCTION full text sources ADS |