Established that observed AGN properties are dominated by their orientation to the line of sight. Developed from first principles a quantitative formalism to relate numbers and luminosities of AGN of different orientations. In a seminal series of papers, applied formalism to samples of radio-loud AGN, for the first time placing on a quantitative basis the relation of blazars and quasars to radio galaxies, which firmly established the basic correctness of the unification scenario for Active Galactic Nuclei.
Key Papers1:
Luminosity Enhancement in Relativistic Jets and Altered Luminosity Functions for Beamed Objects C. M. Urry and R. A. Shafer, 1984, ApJ, 280, 569-573
Fanaroff-Riley I Galaxies as the Parent Population of BL Lacertae Objects. I. X-Ray Constraints P. Padovani and C. M. Urry, 1990, ApJ, 356, 75-82
Fanaroff-Riley I Galaxies as the Parent Population of BL Lacertae Objects. II. Optical Constraints P. Padovani and C. M. Urry, 1991, ApJ, 368, 373-379
Altered Luminosity Functions for Relativistically Beamed Objects. II. Distribution of Lorentz Factors and Complex Parent Luminosity Functions C. M. Urry and P. Padovani, 1991, ApJ, 371, 60-68
The Effect of Anisotropic Emission from Thick Accretion Disks on the Luminosity Functions of AGN C. M. Urry, P. Marziani, and M. Calvani, 1991, ApJ, 371, 510-514
Fanaroff-Riley I Galaxies as the Parent Population of BL Lacertae Objects. III. Radio Constraints C. M. Urry, P. Padovani, and M. Stickel, 1991, ApJ, 382, 501-507
Luminosity Functions, Relativistic Beaming, and Unified Theories of Radio Sources P. Padovani and C. M. Urry, 1992, ApJ, 387, 449-457
Unified Schemes for Radio-Loud Active Galactic Nuclei C. M. Urry and Paolo Padovani, 1995, PASP, 107, 803-845
The AGN Paradigm for Radio-Loud Objects C. M. Urry, 2003, in Active Galactic Nuclei: from Central Engine to Host Galaxy, ed. S. Collin, F. Combes, and I. Shlosman, ASP Conf. Series Vol. 290, pp. 3-10 (Review)
AGN Unification: An Update C. M. Urry, 2004, in AGN Physics with the Sloan Digital Sky Survey, ed. G. T. Richards \& P. B. Hall, (ASP Conf. Series), p. 49 (Review)
1Some publications, in this area and others, have been led by (or prominent roles have been played by) my graduate students, including Pian, Sambruna, O’Dowd, Woo, Treister, van Duyne, Simmons, Virani; undergraduate students including Cheung, Tanihata; postdocs including Padovani, Pesce, Scarpa, Grandi, Uchiyama.