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Session 119 - QSOs and BL Lacs.
Oral session, Thursday, January 18
1st Floor, La Villita Assembly Building
The gas producing the broad absorption lines (BALs) of QSOs appears to have heavy element abundances one to two orders-of-magnitude great than solar (Turnshek 1995, ESO Workshop on QSO Absorption Lines; Korista et al. 1995, Ap. J., in press). Junkarrinen et al. (1995, B.A.A.S., 27, 872; also Junkarrinen 1995, personal communic.) find P/C about 65 times solar in one BAL QSO. Abundances of C, N, O, and Si estimated for a small sample of BAL QSOs are consistent with the distribution of abundances in Galactic novae Andreä et al. 1994, Astr. Ap., 291, 869). The high P/C ratio is consistent with theoretical models of nova explosions on O-Ne-Mg white dwarfs (Politano et al., Ap. J., 448, 807). This raises the possibility that the BAL gas may largely consist of the ejecta of novae occuring \sim10^18 cm from the central source. This gas presumably is accelerated to high outflow velocities by the radiation pressure of the QSO luminosity or a fast moving wind.
Ordinary novae in an extremely massive nuclear star cluster may produce sufficient material to explain the \sim10 percent incidence of BALs among all QSOs. The combination of high metallicity and small mass per event helps novae to be competitive with other sources of material, such as planetary nebulae, supernovae, and stellar winds. Alternatively, accretion onto solitary white dwarfs passing through an accretion disk surrounding a supermassive black hole may fuel nova outbursts (... Artymowicz et al. 1993, Ap. J., 409, 592.). This mechanism may provide sufficent nova material with a relatively modest nuclear star cluster if the cluster is substantially corotating with the accretion disk.
Program listing for Thursday