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Session 84 - QSOs and BL Lacs.
Display session, Wednesday, January 17
North Banquet Hall, Convention Center

[84.14] Constraints on Relativistic Beaming Models of BL Lacs

R. I. Kollgaard, S. A. Laurent-Muehleisen, E. D. Feigelson (Penn State), C. Palma (Univ of Va.)

We have recently completed a VLA imaging survey of the radio properties of the HEAO-1 sample of X-ray selected BL Lacertae objects (XBLs). The core and extended luminosities are compared with similar data for radio-selected BL Lacs (RBLs) and radio galaxies. We find that all three classes show parallel correlations between the radio luminosity of the core and extended radio luminosities with P_ext \propto P_core^1.2. The cores of the XBLs and RBLs are on average 160 and 4000 times (respectively) stronger than the galaxy cores when normalized to a constant extended radio luminosity. This result is consistent with the expectations of unified schemes connecting BL Lacertae objects and radio galaxies via different jet orientations. The high level of core enhancement in BL Lacertae objects is incompatible with simple models assuming a continuous jet, and instead requires jets with a few discrete components. Assuming a constant jet Lorentz factor \Gamma, the core enhancements require that \Gamma > 4.5 and probably exceed \Gamma = 6, with average angles to the line of sight of approximately 60^\circ, 20^\circ, and 10^\circ for the galaxies, XBLs, and RBLs (respectively).

Program listing for Wednesday